Author name code: roth
ADS astronomy entries on 2022-09-14
author:(="Roth, Markus" OR ="Roth, M.") -aff:("Karlsruhe" OR "La Serena" OR "Seattle") -abs:("Auger" OR "earthquake" OR "Vizier" OR "Lunar" OR "crystalline" OR "KASCADE" OR "PRAXIS")
------------------------------------------------------------------------
Title: Ultra-High-Energy Cosmic Rays: The Intersection of the Cosmic
and Energy Frontiers
Authors: Coleman, A.; Eser, J.; Mayotte, E.; Sarazin, F.; Schröder,
F. G.; Soldin, D.; Venters, T. M.; Aloisio, R.; Alvarez-Muñiz,
J.; Alves Batista, R.; Bergman, D.; Bertaina, M.; Caccianiga,
L.; Deligny, O.; Dembinski, H. P.; Denton, P. B.; di Matteo, A.;
Globus, N.; Glombitza, J.; Golup, G.; Haungs, A.; Hörandel, J. R.;
Jaffe, T. R.; Kelley, J. L.; Krizmanic, J. F.; Lu, L.; Matthews,
J. N.; Mariş, I.; Mussa, R.; Oikonomou, F.; Pierog, T.; Santos,
E.; Tinyakov, P.; Tsunesada, Y.; Unger, M.; Yushkov, A.; Albrow,
M. G.; Anchordoqui, L. A.; Andeen, K.; Arnone, E.; Barghini, D.;
Bechtol, E.; Bellido, J. A.; Casolino, M.; Castellina, A.; Cazon,
L.; Conceição, R.; Cremonini, R.; Dujmovic, H.; Engel, R.; Farrar,
G.; Fenu, F.; Ferrarese, S.; Fujii, T.; Gardiol, D.; Gritsevich, M.;
Homola, P.; Huege, T.; Kampert, K. -H.; Kang, D.; Kido, E.; Klimov,
P.; Kotera, K.; Kozelov, B.; Leszczyńska, A.; Madsen, J.; Marcelli,
L.; Marisaldi, M.; Martineau-Huynh, O.; Mayotte, S.; Mulrey, K.;
Murase, K.; Muzio, M. S.; Ogio, S.; Olinto, A. V.; Onel, Y.; Paul,
T.; Piotrowski, L.; Plum, M.; Pont, B.; Reininghaus, M.; Riedel,
B.; Riehn, F.; Roth, M.; Sako, T.; Schlüter, F.; Shoemaker, D.;
Sidhu, J.; Sidelnik, I.; Timmermans, C.; Tkachenko, O.; Veberič,
D.; Verpoest, S.; Verzi, V.; Vícha, J.; Winn, D.; Zas, E.; Zotov, M.
Bibcode: 2022arXiv220505845C
Altcode:
The present white paper is submitted as part of the "Snowmass" process
to help inform the long-term plans of the United States Department of
Energy and the National Science Foundation for high-energy physics. It
summarizes the science questions driving the Ultra-High-Energy
Cosmic-Ray (UHECR) community and provides recommendations on the
strategy to answer them in the next two decades.
Title: A complete model of the signal in surface detector arrays and
its application for the reconstruction of mass-sensitive observables.
Authors: Stadelmaier, M.; Roth, M.; Schmidt, D.; Veberic, D.
Bibcode: 2022icrc.confE.432S
Altcode: 2022PoS...395E.432S
No abstract at ADS
Title: The depth of the shower maximum of air showers measured
with AERA
Authors: Pont, B.; The Pierre Auger Collaboration; Abreu, P.; Aglietta,
M.; Albury, J. M.; Allekotte, I.; Almela, A.; Alvarez-Muniz, J.;
Alves Batista, R.; Anastasi, G. A.; Anchordoqui, L. A.; Andrada,
B.; Andringa, S.; Aramo, C.; Araújo Ferreira, P. R.; Arteaga
Velazquez, J. C.; Asorey, H. G.; Assis, P.; Avila, G.; Badescu,
A. M.; Bakalova, A.; Balaceanu, A.; Barbato, F.; Barreira Luz, R. J.;
Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou,
X.; Biermann, P. L.; Binet, V.; Bismark, K.; Bister, T.; Biteau,
J.; Blazek, J.; Bleve, C.; Bohacova, M.; Boncioli, D.; Bonifazi,
C.; Bonneau Arbeletche, L.; Borodai, N.; Botti, A. M.; Brack, J.;
Bretz, T.; Brichetto Orchera, P. G.; Briechle, F. L.; Buchholz, P.;
Bueno, A.; Buitink, S.; Buscemi, M.; Büsken, M.; Caballero-Mora,
K. S.; Caccianiga, L.; Canfora, F.; Caracas, I.; Carceller, J. M.;
Caruso, R.; Castellina, A.; Catalani, F.; Cataldi, G.; Cazon,
L.; Cerda, M.; Chinellato, J. A.; Chudoba, J.; Chytka, L.; Clay,
R. W.; Cobos Cerutti, A.; Colalillo, R.; Coleman, A.; Coluccia,
M. R.; Conceição, R.; Condorelli, A.; Consolati, G.; Contreras,
F.; Convenga, F.; Correia dos Santos, D.; Covault, C.; Dasso, S.;
Daumiller, K.; Dawson, B. R.; Day, J. A.; de Almeida, R. M.; de Jesús,
J.; de Jong, S. J.; De Mauro, G.; de Mello Neto, J.; De Mitri, I.;
de Oliveira, J.; de Oliveira Franco, D.; de Palma, F.; de Souza, V.;
De Vito, E.; del Río, M.; Deligny, O.; Deval, L.; di Matteo, A.;
Dobrigkeit, C.; D'Olivo, J. C.; Domingues Mendes, L. M.; dos Anjos,
R.; dos Santos, D.; Dova, M. T.; Ebr, J.; Engel, R.; Epicoco, I.;
Erdmann, M.; Escobar, C. O.; Etchegoyen, A.; Falcke, H.; Farmer, J.;
Farrar, G. R.; Fauth, A.; Fazzini, N.; Feldbusch, F.; Fenu, F.; Fick,
B.; Figueira, J. M.; Filipcic, A.; Fitoussi, T.; Fodran, T.; Freire,
M. M.; Fujii, T.; Fuster, A.; Galea, C.; Galelli, C.; García, B.;
García Vegas, A. L.; Gemmeke, H.; Gesualdi, F.; Gherghel-Lascu,
A.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Glombitza, J.; Gobbi,
F.; Gollan, F.; Golup, G.; Gómez Berisso, M.; Gómez Vitale, P. F.;
Gongora, J. P.; González, J. M.; Gonzalez, N. M.; Goos, I.; Gora,
D.; Gorgi, A.; Gottowik, M.; Grubb, T. D.; Guarino, F.; Guedes, G.;
Guido, E.; Hahn, S.; Hamal, P.; Hampel, M. R.; Hansen, P. M.; Harari,
D.; Harvey, V. M.; Haungs, A.; Hebbeker, T.; Heck, D.; Hill, G. C.;
Hojvat, C.; Hörandel, J.; Horvath, P.; Hrabovsky, M.; Huege, T.;
Insolia, A.; Isar, P. G.; Janecek, P.; Johnsen, J. A.; Juryšek, J.;
Kääpä, A.; Kampert, K. H.; Karastathis, N.; Keilhauer, B.; Kemp,
J.; Khakurdikar, A.; Kizakke Covilakam, V. V.; Klages, H.; Kleifges,
M.; Kleinfeller, J.; Köpke, M.; Kunka, N.; Lago, B. L.; Lang, R. G.;
Langner, N.; Leigui de Oliveira, M. A.; Lenok, V.; Letessier-Selvon,
A.; Lhenry-Yvon, I.; Lo Presti, D.; Lopes, L.; López, R.; Lu, L.;
Luce, Q.; Lundquist, J. P.; Machado Payeras, A.; Mancarella, G.;
Mandat, D.; Manning, B. C.; Manshanden, J.; Mantsch, P.; Marafico, S.;
Mariazzi, A.; Maris, I. C.; Marsella, G.; Martello, D.; Martinelli,
S.; Martínez Bravo, O.; Mastrodicasa, M.; Mathes, H. J.; Matthews,
J.; Matthiae, G.; Mayotte, E.; Mazur, P.; Medina-Tanco, G.; Melo,
D.; Menshikov, A.; Merenda, K. D.; Michal, S.; Micheletti, M. I.;
Miramonti, L.; Mollerach, S.; Montanet, F.; Morello, C.; Mostafa, M.;
Müller, A. L.; Muller, M. A.; Mulrey, K.; Mussa, R.; Muzio, M. S.;
Namasaka, W. M.; Nasr-Esfahani, A.; Nellen, L.; Niculescu-Oglinzanu,
M.; Niechciol, M.; Nitz, D.; Nosek, D.; Novotný, V.; Nozka, L.;
Nucita, A.; Nunez, L. A.; Palatka, M.; Pallotta, J.; Papenbreer,
P.; Parente, G.; Parra, A.; Pawlowsky, J.; Pech, M.; Pedreira, F.;
Pękala, J.; Pelayo, R.; Peña-Rodríguez, J.; Pereira Martins,
E. E.; Perez Armand, J.; Pérez Bertolli, C.; Perlin, M.; Perrone,
L.; Petrera, S.; Pierog, T.; Pimenta, M.; Pirronello, V.; Platino,
M.; Pothast, M.; Privitera, P.; Prouza, M.; Puyleart, A.; Querchfeld,
S.; Rautenberg, J.; Ravignani, D.; Reininghaus, M.; Ridky, J.; Riehn,
F.; Risse, M.; Rizi, V.; Rodrigues de Carvalho, W.; Rodriguez Rojo,
J. R.; Roncoroni, M. J.; Rossoni, S.; Roth, M.; Roulet, E.; Rovero,
A.; Ruehl, P.; Saftoiu, A.; Salamida, F.; Salazar, H. I.; Salina,
G.; Sanabria Gomez, J.; Sánchez, F. A.; Santos, E. M.; Santos, E.;
Sarazin, F.; Sarmento, R.; Sarmiento-Cano, C.; Sato, R.; Savina, P.;
Schäfer, C. M.; Scherini, V.; Schieler, H.; Schimassek, M.; Schimp,
M.; Schlüter, F.; Schmidt, D.; Scholten, O.; Schovanek, P.; Schröder,
F. G.; Schröder, S.; Schulte, J.; Sciutto, S.; Scornavacche, M.;
Segreto, A.; Sehgal, S.; Shellard, R. C.; Sigl, G.; Silli, G.; Sima,
O.; Smida, R.; Sommers, P.; Soriano, J. F.; Souchard, J.; Squartini,
R.; Stadelmaier, M.; Stanca, D.; Stanič, S.; Stasielak, J.; Stassi,
P.; Streich, A.; Suárez-Durán, M.; Sudholz, T.; Suomijarvi, T.;
Supanitsky, A. D.; Szadkowski, Z.; Tapia, A.; Taricco, C.; Timmermans,
C.; Tkachenko, O.; Tobiska, P.; Todero Peixoto, C. J.; Tomé, B.;
Torrès, Z.; Travaini, A.; Travnicek, P.; Trimarelli, C.; Tueros, M.;
Ulrich, R.; Unger, M.; Vaclavek, L.; Vacula, M.; Valdés Galicia,
J. F.; Valore, L.; Varela, E.; Vásquez-Ramírez, A.; Veberic, D.;
Ventura, C.; Vergara Quispe, I. D.; Verzi, V.; Vicha, J.; Vink, J.;
Vorobiov, S.; Wahlberg, H.; Watanabe, C. K. O.; Watson, A.; Weber,
M.; Weindl, A.; Wiencke, L.; Wilczyński, H.; Wirtz, M.; Wittkowski,
D.; Wundheiler, B.; Yushkov, A.; Zapparrata, O.; Zas, E.; Zavrtanik,
D.; Zavrtanik, M.; Zehrer, L.
Bibcode: 2022icrc.confE.387P
Altcode: 2022PoS...395E.387P
No abstract at ADS
Title: Update of the Offline Framework for AugerPrime
Authors: Nellen, L.; The Pierre Auger Collaboration; Abreu, P.;
Aglietta, M.; Albury, J. M.; Allekotte, I.; Almela, A.; Alvarez-Muniz,
J.; Alves Batista, R.; Anastasi, G. A.; Anchordoqui, L. A.; Andrada,
B.; Andringa, S.; Aramo, C.; Araújo Ferreira, P. R.; Arteaga
Velazquez, J. C.; Asorey, H. G.; Assis, P.; Avila, G.; Badescu,
A. M.; Bakalova, A.; Balaceanu, A.; Barbato, F.; Barreira Luz, R. J.;
Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou,
X.; Biermann, P. L.; Binet, V.; Bismark, K.; Bister, T.; Biteau,
J.; Blazek, J.; Bleve, C.; Bohacova, M.; Boncioli, D.; Bonifazi,
C.; Bonneau Arbeletche, L.; Borodai, N.; Botti, A. M.; Brack, J.;
Bretz, T.; Brichetto Orchera, P. G.; Briechle, F. L.; Buchholz, P.;
Bueno, A.; Buitink, S.; Buscemi, M.; Büsken, M.; Caballero-Mora,
K. S.; Caccianiga, L.; Canfora, F.; Caracas, I.; Carceller, J. M.;
Caruso, R.; Castellina, A.; Catalani, F.; Cataldi, G.; Cazon,
L.; Cerda, M.; Chinellato, J. A.; Chudoba, J.; Chytka, L.; Clay,
R. W.; Cobos Cerutti, A.; Colalillo, R.; Coleman, A.; Coluccia,
M. R.; Conceição, R.; Condorelli, A.; Consolati, G.; Contreras,
F.; Convenga, F.; Correia dos Santos, D.; Covault, C.; Dasso, S.;
Daumiller, K.; Dawson, B. R.; Day, J. A.; de Almeida, R. M.; de Jesús,
J.; de Jong, S. J.; De Mauro, G.; de Mello Neto, J.; De Mitri, I.;
de Oliveira, J.; de Oliveira Franco, D.; de Palma, F.; de Souza, V.;
De Vito, E.; del Río, M.; Deligny, O.; Deval, L.; di Matteo, A.;
Dobrigkeit, C.; D'Olivo, J. C.; Domingues Mendes, L. M.; dos Anjos,
R.; dos Santos, D.; Dova, M. T.; Ebr, J.; Engel, R.; Epicoco, I.;
Erdmann, M.; Escobar, C. O.; Etchegoyen, A.; Falcke, H.; Farmer, J.;
Farrar, G. R.; Fauth, A.; Fazzini, N.; Feldbusch, F.; Fenu, F.; Fick,
B.; Figueira, J. M.; Filipcic, A.; Fitoussi, T.; Fodran, T.; Freire,
M. M.; Fujii, T.; Fuster, A.; Galea, C.; Galelli, C.; García, B.;
García Vegas, A. L.; Gemmeke, H.; Gesualdi, F.; Gherghel-Lascu,
A.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Glombitza, J.; Gobbi,
F.; Gollan, F.; Golup, G.; Gómez Berisso, M.; Gómez Vitale, P. F.;
Gongora, J. P.; González, J. M.; Gonzalez, N. M.; Goos, I.; Gora,
D.; Gorgi, A.; Gottowik, M.; Grubb, T. D.; Guarino, F.; Guedes, G.;
Guido, E.; Hahn, S.; Hamal, P.; Hampel, M. R.; Hansen, P. M.; Harari,
D.; Harvey, V. M.; Haungs, A.; Hebbeker, T.; Heck, D.; Hill, G. C.;
Hojvat, C.; Hörandel, J.; Horvath, P.; Hrabovsky, M.; Huege, T.;
Insolia, A.; Isar, P. G.; Janecek, P.; Johnsen, J. A.; Juryšek, J.;
Kääpä, A.; Kampert, K. H.; Karastathis, N.; Keilhauer, B.; Kemp,
J.; Khakurdikar, A.; Kizakke Covilakam, V. V.; Klages, H.; Kleifges,
M.; Kleinfeller, J.; Köpke, M.; Kunka, N.; Lago, B. L.; Lang, R. G.;
Langner, N.; Leigui de Oliveira, M. A.; Lenok, V.; Letessier-Selvon,
A.; Lhenry-Yvon, I.; Lo Presti, D.; Lopes, L.; López, R.; Lu, L.;
Luce, Q.; Lundquist, J. P.; Machado Payeras, A.; Mancarella, G.;
Mandat, D.; Manning, B. C.; Manshanden, J.; Mantsch, P.; Marafico, S.;
Mariazzi, A.; Maris, I. C.; Marsella, G.; Martello, D.; Martinelli,
S.; Martínez Bravo, O.; Mastrodicasa, M.; Mathes, H. J.; Matthews,
J.; Matthiae, G.; Mayotte, E.; Mazur, P.; Medina-Tanco, G.; Melo,
D.; Menshikov, A.; Merenda, K. D.; Michal, S.; Micheletti, M. I.;
Miramonti, L.; Mollerach, S.; Montanet, F.; Morello, C.; Mostafa,
M.; Müller, A. L.; Muller, M. A.; Mulrey, K.; Mussa, R.; Muzio,
M. S.; Namasaka, W. M.; Nasr-Esfahani, A.; Niculescu-Oglinzanu, M.;
Niechciol, M.; Nitz, D.; Nosek, D.; Novotný, V.; Nozka, L.; Nucita,
A.; Nunez, L. A.; Palatka, M.; Pallotta, J.; Papenbreer, P.; Parente,
G.; Parra, A.; Pawlowsky, J.; Pech, M.; Pedreira, F.; Pękala, J.;
Pelayo, R.; Peña-Rodríguez, J.; Pereira Martins, E. E.; Perez
Armand, J.; Pérez Bertolli, C.; Perlin, M.; Perrone, L.; Petrera,
S.; Pierog, T.; Pimenta, M.; Pirronello, V.; Platino, M.; Pont, B.;
Pothast, M.; Privitera, P.; Prouza, M.; Puyleart, A.; Querchfeld,
S.; Rautenberg, J.; Ravignani, D.; Reininghaus, M.; Ridky, J.; Riehn,
F.; Risse, M.; Rizi, V.; Rodrigues de Carvalho, W.; Rodriguez Rojo,
J. R.; Roncoroni, M. J.; Rossoni, S.; Roth, M.; Roulet, E.; Rovero,
A.; Ruehl, P.; Saftoiu, A.; Salamida, F.; Salazar, H. I.; Salina,
G.; Sanabria Gomez, J.; Sánchez, F. A.; Santos, E. M.; Santos, E.;
Sarazin, F.; Sarmento, R.; Sarmiento-Cano, C.; Sato, R.; Savina, P.;
Schäfer, C. M.; Scherini, V.; Schieler, H.; Schimassek, M.; Schimp,
M.; Schlüter, F.; Schmidt, D.; Scholten, O.; Schovanek, P.; Schröder,
F. G.; Schröder, S.; Schulte, J.; Sciutto, S.; Scornavacche, M.;
Segreto, A.; Sehgal, S.; Shellard, R. C.; Sigl, G.; Silli, G.; Sima,
O.; Smida, R.; Sommers, P.; Soriano, J. F.; Souchard, J.; Squartini,
R.; Stadelmaier, M.; Stanca, D.; Stanič, S.; Stasielak, J.; Stassi,
P.; Streich, A.; Suárez-Durán, M.; Sudholz, T.; Suomijarvi, T.;
Supanitsky, A. D.; Szadkowski, Z.; Tapia, A.; Taricco, C.; Timmermans,
C.; Tkachenko, O.; Tobiska, P.; Todero Peixoto, C. J.; Tomé, B.;
Torrès, Z.; Travaini, A.; Travnicek, P.; Trimarelli, C.; Tueros, M.;
Ulrich, R.; Unger, M.; Vaclavek, L.; Vacula, M.; Valdés Galicia,
J. F.; Valore, L.; Varela, E.; Vásquez-Ramírez, A.; Veberic, D.;
Ventura, C.; Vergara Quispe, I. D.; Verzi, V.; Vicha, J.; Vink, J.;
Vorobiov, S.; Wahlberg, H.; Watanabe, C. K. O.; Watson, A.; Weber,
M.; Weindl, A.; Wiencke, L.; Wilczyński, H.; Wirtz, M.; Wittkowski,
D.; Wundheiler, B.; Yushkov, A.; Zapparrata, O.; Zas, E.; Zavrtanik,
D.; Zavrtanik, M.; Zehrer, L.
Bibcode: 2022icrc.confE.250N
Altcode: 2022PoS...395E.250N
No abstract at ADS
Title: AugerPrime Upgraded Electronics
Authors: Marsella, G.; The Pierre Auger Collaboration; Abreu, P.;
Aglietta, M.; Albury, J. M.; Allekotte, I.; Almela, A.; Alvarez-Muniz,
J.; Alves Batista, R.; Anastasi, G. A.; Anchordoqui, L. A.; Andrada,
B.; Andringa, S.; Aramo, C.; Araújo Ferreira, P. R.; Arteaga
Velazquez, J. C.; Asorey, H. G.; Assis, P.; Avila, G.; Badescu,
A. M.; Bakalova, A.; Balaceanu, A.; Barbato, F.; Barreira Luz, R. J.;
Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou,
X.; Biermann, P. L.; Binet, V.; Bismark, K.; Bister, T.; Biteau,
J.; Blazek, J.; Bleve, C.; Bohacova, M.; Boncioli, D.; Bonifazi, C.;
Bonneau Arbeletche, L.; Borodai, N.; Botti, A. M.; Brack, J.; Bretz,
T.; Brichetto Orchera, P. G.; Briechle, F. L.; Buchholz, P.; Bueno,
A.; Buitink, S.; Buscemi, M.; Büsken, M.; Caballero-Mora, K. S.;
Caccianiga, L.; Canfora, F.; Caracas, I.; Carceller, J. M.; Caruso,
R.; Castellina, A.; Catalani, F.; Cataldi, G.; Cazon, L.; Cerda, M.;
Chinellato, J. A.; Chudoba, J.; Chytka, L.; Clay, R. W.; Cobos Cerutti,
A.; Colalillo, R.; Coleman, A.; Coluccia, M. R.; Conceição, R.;
Condorelli, A.; Consolati, G.; Contreras, F.; Convenga, F.; Correia dos
Santos, D.; Covault, C.; Dasso, S.; Daumiller, K.; Dawson, B. R.; Day,
J. A.; de Almeida, R. M.; de Jesús, J.; de Jong, S. J.; De Mauro,
G.; de Mello Neto, J.; De Mitri, I.; de Oliveira, J.; de Oliveira
Franco, D.; de Palma, F.; de Souza, V.; De Vito, E.; del Río, M.;
Deligny, O.; Deval, L.; di Matteo, A.; Dobrigkeit, C.; D'Olivo,
J. C.; Domingues Mendes, L. M.; dos Anjos, R.; dos Santos, D.; Dova,
M. T.; Ebr, J.; Engel, R.; Epicoco, I.; Erdmann, M.; Escobar, C. O.;
Etchegoyen, A.; Falcke, H.; Farmer, J.; Farrar, G. R.; Fauth, A.;
Fazzini, N.; Feldbusch, F.; Fenu, F.; Fick, B.; Figueira, J. M.;
Filipcic, A.; Fitoussi, T.; Fodran, T.; Freire, M. M.; Fujii, T.;
Fuster, A.; Galea, C.; Galelli, C.; García, B.; García Vegas, A. L.;
Gemmeke, H.; Gesualdi, F.; Gherghel-Lascu, A.; Ghia, P. L.; Giaccari,
U.; Giammarchi, M.; Glombitza, J.; Gobbi, F.; Gollan, F.; Golup, G.;
Gómez Berisso, M.; Gómez Vitale, P. F.; Gongora, J. P.; González,
J. M.; Gonzalez, N. M.; Goos, I.; Gora, D.; Gorgi, A.; Gottowik, M.;
Grubb, T. D.; Guarino, F.; Guedes, G.; Guido, E.; Hahn, S.; Hamal,
P.; Hampel, M. R.; Hansen, P. M.; Harari, D.; Harvey, V. M.; Haungs,
A.; Hebbeker, T.; Heck, D.; Hill, G. C.; Hojvat, C.; Hörandel, J.;
Horvath, P.; Hrabovsky, M.; Huege, T.; Insolia, A.; Isar, P. G.;
Janecek, P.; Johnsen, J. A.; Juryšek, J.; Kääpä, A.; Kampert,
K. H.; Karastathis, N.; Keilhauer, B.; Kemp, J.; Khakurdikar, A.;
Kizakke Covilakam, V. V.; Klages, H.; Kleifges, M.; Kleinfeller, J.;
Köpke, M.; Kunka, N.; Lago, B. L.; Lang, R. G.; Langner, N.; Leigui
de Oliveira, M. A.; Lenok, V.; Letessier-Selvon, A.; Lhenry-Yvon, I.;
Lo Presti, D.; Lopes, L.; López, R.; Lu, L.; Luce, Q.; Lundquist,
J. P.; Machado Payeras, A.; Mancarella, G.; Mandat, D.; Manning, B. C.;
Manshanden, J.; Mantsch, P.; Marafico, S.; Mariazzi, A.; Maris, I. C.;
Martello, D.; Martinelli, S.; Martínez Bravo, O.; Mastrodicasa, M.;
Mathes, H. J.; Matthews, J.; Matthiae, G.; Mayotte, E.; Mazur, P.;
Medina-Tanco, G.; Melo, D.; Menshikov, A.; Merenda, K. D.; Michal,
S.; Micheletti, M. I.; Miramonti, L.; Mollerach, S.; Montanet, F.;
Morello, C.; Mostafa, M.; Müller, A. L.; Muller, M. A.; Mulrey,
K.; Mussa, R.; Muzio, M. S.; Namasaka, W. M.; Nasr-Esfahani, A.;
Nellen, L.; Niculescu-Oglinzanu, M.; Niechciol, M.; Nitz, D.; Nosek,
D.; Novotný, V.; Nozka, L.; Nucita, A.; Nunez, L. A.; Palatka, M.;
Pallotta, J.; Papenbreer, P.; Parente, G.; Parra, A.; Pawlowsky, J.;
Pech, M.; Pedreira, F.; Pękala, J.; Pelayo, R.; Peña-Rodríguez,
J.; Pereira Martins, E. E.; Perez Armand, J.; Pérez Bertolli,
C.; Perlin, M.; Perrone, L.; Petrera, S.; Pierog, T.; Pimenta, M.;
Pirronello, V.; Platino, M.; Pont, B.; Pothast, M.; Privitera, P.;
Prouza, M.; Puyleart, A.; Querchfeld, S.; Rautenberg, J.; Ravignani,
D.; Reininghaus, M.; Ridky, J.; Riehn, F.; Risse, M.; Rizi, V.;
Rodrigues de Carvalho, W.; Rodriguez Rojo, J. R.; Roncoroni, M. J.;
Rossoni, S.; Roth, M.; Roulet, E.; Rovero, A.; Ruehl, P.; Saftoiu,
A.; Salamida, F.; Salazar, H. I.; Salina, G.; Sanabria Gomez, J.;
Sánchez, F. A.; Santos, E. M.; Santos, E.; Sarazin, F.; Sarmento, R.;
Sarmiento-Cano, C.; Sato, R.; Savina, P.; Schäfer, C. M.; Scherini,
V.; Schieler, H.; Schimassek, M.; Schimp, M.; Schlüter, F.; Schmidt,
D.; Scholten, O.; Schovanek, P.; Schröder, F. G.; Schröder, S.;
Schulte, J.; Sciutto, S.; Scornavacche, M.; Segreto, A.; Sehgal, S.;
Shellard, R. C.; Sigl, G.; Silli, G.; Sima, O.; Smida, R.; Sommers,
P.; Soriano, J. F.; Souchard, J.; Squartini, R.; Stadelmaier, M.;
Stanca, D.; Stanič, S.; Stasielak, J.; Stassi, P.; Streich, A.;
Suárez-Durán, M.; Sudholz, T.; Suomijarvi, T.; Supanitsky, A. D.;
Szadkowski, Z.; Tapia, A.; Taricco, C.; Timmermans, C.; Tkachenko, O.;
Tobiska, P.; Todero Peixoto, C. J.; Tomé, B.; Torrès, Z.; Travaini,
A.; Travnicek, P.; Trimarelli, C.; Tueros, M.; Ulrich, R.; Unger, M.;
Vaclavek, L.; Vacula, M.; Valdés Galicia, J. F.; Valore, L.; Varela,
E.; Vásquez-Ramírez, A.; Veberic, D.; Ventura, C.; Vergara Quispe,
I. D.; Verzi, V.; Vicha, J.; Vink, J.; Vorobiov, S.; Wahlberg, H.;
Watanabe, C. K. O.; Watson, A.; Weber, M.; Weindl, A.; Wiencke, L.;
Wilczyński, H.; Wirtz, M.; Wittkowski, D.; Wundheiler, B.; Yushkov,
A.; Zapparrata, O.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zehrer, L.
Bibcode: 2022icrc.confE.230M
Altcode: 2022PoS...395E.230M
No abstract at ADS
Title: A combined fit of energy spectrum, shower depth distribution
and arrival directions to constrain astrophysical models of UHECR
sources
Authors: Bister, T.; The Pierre Auger Collaboration; Abreu, P.;
Aglietta, M.; Albury, J. M.; Allekotte, I.; Almela, A.; Alvarez-Muniz,
J.; Alves Batista, R.; Anastasi, G. A.; Anchordoqui, L. A.; Andrada,
B.; Andringa, S.; Aramo, C.; Araújo Ferreira, P. R.; Arteaga
Velazquez, J. C.; Asorey, H. G.; Assis, P.; Avila, G.; Badescu,
A. M.; Bakalova, A.; Balaceanu, A.; Barbato, F.; Barreira Luz, R. J.;
Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou, X.;
Biermann, P. L.; Binet, V.; Bismark, K.; Biteau, J.; Blazek, J.; Bleve,
C.; Bohacova, M.; Boncioli, D.; Bonifazi, C.; Bonneau Arbeletche, L.;
Borodai, N.; Botti, A. M.; Brack, J.; Bretz, T.; Brichetto Orchera,
P. G.; Briechle, F. L.; Buchholz, P.; Bueno, A.; Buitink, S.; Buscemi,
M.; Büsken, M.; Caballero-Mora, K. S.; Caccianiga, L.; Canfora, F.;
Caracas, I.; Carceller, J. M.; Caruso, R.; Castellina, A.; Catalani,
F.; Cataldi, G.; Cazon, L.; Cerda, M.; Chinellato, J. A.; Chudoba, J.;
Chytka, L.; Clay, R. W.; Cobos Cerutti, A.; Colalillo, R.; Coleman,
A.; Coluccia, M. R.; Conceição, R.; Condorelli, A.; Consolati,
G.; Contreras, F.; Convenga, F.; Correia dos Santos, D.; Covault,
C.; Dasso, S.; Daumiller, K.; Dawson, B. R.; Day, J. A.; de Almeida,
R. M.; de Jesús, J.; de Jong, S. J.; De Mauro, G.; de Mello Neto,
J.; De Mitri, I.; de Oliveira, J.; de Oliveira Franco, D.; de Palma,
F.; de Souza, V.; De Vito, E.; del Río, M.; Deligny, O.; Deval,
L.; di Matteo, A.; Dobrigkeit, C.; D'Olivo, J. C.; Domingues Mendes,
L. M.; dos Anjos, R.; dos Santos, D.; Dova, M. T.; Ebr, J.; Engel, R.;
Epicoco, I.; Erdmann, M.; Escobar, C. O.; Etchegoyen, A.; Falcke, H.;
Farmer, J.; Farrar, G. R.; Fauth, A.; Fazzini, N.; Feldbusch, F.; Fenu,
F.; Fick, B.; Figueira, J. M.; Filipcic, A.; Fitoussi, T.; Fodran, T.;
Freire, M. M.; Fujii, T.; Fuster, A.; Galea, C.; Galelli, C.; García,
B.; García Vegas, A. L.; Gemmeke, H.; Gesualdi, F.; Gherghel-Lascu,
A.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Glombitza, J.; Gobbi,
F.; Gollan, F.; Golup, G.; Gómez Berisso, M.; Gómez Vitale, P. F.;
Gongora, J. P.; González, J. M.; Gonzalez, N. M.; Goos, I.; Gora,
D.; Gorgi, A.; Gottowik, M.; Grubb, T. D.; Guarino, F.; Guedes, G.;
Guido, E.; Hahn, S.; Hamal, P.; Hampel, M. R.; Hansen, P. M.; Harari,
D.; Harvey, V. M.; Haungs, A.; Hebbeker, T.; Heck, D.; Hill, G. C.;
Hojvat, C.; Hörandel, J.; Horvath, P.; Hrabovsky, M.; Huege, T.;
Insolia, A.; Isar, P. G.; Janecek, P.; Johnsen, J. A.; Juryšek, J.;
Kääpä, A.; Kampert, K. H.; Karastathis, N.; Keilhauer, B.; Kemp,
J.; Khakurdikar, A.; Kizakke Covilakam, V. V.; Klages, H.; Kleifges,
M.; Kleinfeller, J.; Köpke, M.; Kunka, N.; Lago, B. L.; Lang, R. G.;
Langner, N.; Leigui de Oliveira, M. A.; Lenok, V.; Letessier-Selvon,
A.; Lhenry-Yvon, I.; Lo Presti, D.; Lopes, L.; López, R.; Lu, L.;
Luce, Q.; Lundquist, J. P.; Machado Payeras, A.; Mancarella, G.;
Mandat, D.; Manning, B. C.; Manshanden, J.; Mantsch, P.; Marafico, S.;
Mariazzi, A.; Maris, I. C.; Marsella, G.; Martello, D.; Martinelli,
S.; Martínez Bravo, O.; Mastrodicasa, M.; Mathes, H. J.; Matthews,
J.; Matthiae, G.; Mayotte, E.; Mazur, P.; Medina-Tanco, G.; Melo,
D.; Menshikov, A.; Merenda, K. D.; Michal, S.; Micheletti, M. I.;
Miramonti, L.; Mollerach, S.; Montanet, F.; Morello, C.; Mostafa, M.;
Müller, A. L.; Muller, M. A.; Mulrey, K.; Mussa, R.; Muzio, M. S.;
Namasaka, W. M.; Nasr-Esfahani, A.; Nellen, L.; Niculescu-Oglinzanu,
M.; Niechciol, M.; Nitz, D.; Nosek, D.; Novotný, V.; Nozka, L.;
Nucita, A.; Nunez, L. A.; Palatka, M.; Pallotta, J.; Papenbreer, P.;
Parente, G.; Parra, A.; Pawlowsky, J.; Pech, M.; Pedreira, F.; Pękala,
J.; Pelayo, R.; Peña-Rodríguez, J.; Pereira Martins, E. E.; Perez
Armand, J.; Pérez Bertolli, C.; Perlin, M.; Perrone, L.; Petrera,
S.; Pierog, T.; Pimenta, M.; Pirronello, V.; Platino, M.; Pont, B.;
Pothast, M.; Privitera, P.; Prouza, M.; Puyleart, A.; Querchfeld,
S.; Rautenberg, J.; Ravignani, D.; Reininghaus, M.; Ridky, J.; Riehn,
F.; Risse, M.; Rizi, V.; Rodrigues de Carvalho, W.; Rodriguez Rojo,
J. R.; Roncoroni, M. J.; Rossoni, S.; Roth, M.; Roulet, E.; Rovero,
A.; Ruehl, P.; Saftoiu, A.; Salamida, F.; Salazar, H. I.; Salina,
G.; Sanabria Gomez, J.; Sánchez, F. A.; Santos, E. M.; Santos, E.;
Sarazin, F.; Sarmento, R.; Sarmiento-Cano, C.; Sato, R.; Savina, P.;
Schäfer, C. M.; Scherini, V.; Schieler, H.; Schimassek, M.; Schimp,
M.; Schlüter, F.; Schmidt, D.; Scholten, O.; Schovanek, P.; Schröder,
F. G.; Schröder, S.; Schulte, J.; Sciutto, S.; Scornavacche, M.;
Segreto, A.; Sehgal, S.; Shellard, R. C.; Sigl, G.; Silli, G.; Sima,
O.; Smida, R.; Sommers, P.; Soriano, J. F.; Souchard, J.; Squartini,
R.; Stadelmaier, M.; Stanca, D.; Stanič, S.; Stasielak, J.; Stassi,
P.; Streich, A.; Suárez-Durán, M.; Sudholz, T.; Suomijarvi, T.;
Supanitsky, A. D.; Szadkowski, Z.; Tapia, A.; Taricco, C.; Timmermans,
C.; Tkachenko, O.; Tobiska, P.; Todero Peixoto, C. J.; Tomé, B.;
Torrès, Z.; Travaini, A.; Travnicek, P.; Trimarelli, C.; Tueros, M.;
Ulrich, R.; Unger, M.; Vaclavek, L.; Vacula, M.; Valdés Galicia,
J. F.; Valore, L.; Varela, E.; Vásquez-Ramírez, A.; Veberic, D.;
Ventura, C.; Vergara Quispe, I. D.; Verzi, V.; Vicha, J.; Vink, J.;
Vorobiov, S.; Wahlberg, H.; Watanabe, C. K. O.; Watson, A.; Weber,
M.; Weindl, A.; Wiencke, L.; Wilczyński, H.; Wirtz, M.; Wittkowski,
D.; Wundheiler, B.; Yushkov, A.; Zapparrata, O.; Zas, E.; Zavrtanik,
D.; Zavrtanik, M.; Zehrer, L.
Bibcode: 2022icrc.confE.368B
Altcode: 2022PoS...395E.368B
No abstract at ADS
Title: First results from the AugerPrime Radio Detector
Authors: Fodran, T.; The Pierre Auger Collaboration; Abreu, P.;
Aglietta, M.; Albury, J. M.; Allekotte, I.; Almela, A.; Alvarez-Muniz,
J.; Alves Batista, R.; Anastasi, G. A.; Anchordoqui, L. A.; Andrada,
B.; Andringa, S.; Aramo, C.; Araújo Ferreira, P. R.; Arteaga
Velazquez, J. C.; Asorey, H. G.; Assis, P.; Avila, G.; Badescu,
A. M.; Bakalova, A.; Balaceanu, A.; Barbato, F.; Barreira Luz,
R. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.;
Bertou, X.; Biermann, P. L.; Binet, V.; Bismark, K.; Bister, T.;
Biteau, J.; Blazek, J.; Bleve, C.; Bohacova, M.; Boncioli, D.;
Bonifazi, C.; Bonneau Arbeletche, L.; Borodai, N.; Botti, A. M.;
Brack, J.; Bretz, T.; Brichetto Orchera, P. G.; Briechle, F. L.;
Buchholz, P.; Bueno, A.; Buitink, S.; Buscemi, M.; Büsken, M.;
Caballero-Mora, K. S.; Caccianiga, L.; Canfora, F.; Caracas, I.;
Carceller, J. M.; Caruso, R.; Castellina, A.; Catalani, F.; Cataldi,
G.; Cazon, L.; Cerda, M.; Chinellato, J. A.; Chudoba, J.; Chytka,
L.; Clay, R. W.; Cobos Cerutti, A.; Colalillo, R.; Coleman, A.;
Coluccia, M. R.; Conceição, R.; Condorelli, A.; Consolati, G.;
Contreras, F.; Convenga, F.; Correia dos Santos, D.; Covault, C.;
Dasso, S.; Daumiller, K.; Dawson, B. R.; Day, J. A.; de Almeida,
R. M.; de Jesús, J.; de Jong, S. J.; De Mauro, G.; de Mello Neto,
J.; De Mitri, I.; de Oliveira, J.; de Oliveira Franco, D.; de Palma,
F.; de Souza, V.; De Vito, E.; del Río, M.; Deligny, O.; Deval,
L.; di Matteo, A.; Dobrigkeit, C.; D'Olivo, J. C.; Domingues Mendes,
L. M.; dos Anjos, R.; dos Santos, D.; Dova, M. T.; Ebr, J.; Engel,
R.; Epicoco, I.; Erdmann, M.; Escobar, C. O.; Etchegoyen, A.; Falcke,
H.; Farmer, J.; Farrar, G. R.; Fauth, A.; Fazzini, N.; Feldbusch,
F.; Fenu, F.; Fick, B.; Figueira, J. M.; Filipcic, A.; Fitoussi, T.;
Freire, M. M.; Fujii, T.; Fuster, A.; Galea, C.; Galelli, C.; García,
B.; García Vegas, A. L.; Gemmeke, H.; Gesualdi, F.; Gherghel-Lascu,
A.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Glombitza, J.; Gobbi,
F.; Gollan, F.; Golup, G.; Gómez Berisso, M.; Gómez Vitale, P. F.;
Gongora, J. P.; González, J. M.; Gonzalez, N. M.; Goos, I.; Gora,
D.; Gorgi, A.; Gottowik, M.; Grubb, T. D.; Guarino, F.; Guedes, G.;
Guido, E.; Hahn, S.; Hamal, P.; Hampel, M. R.; Hansen, P. M.; Harari,
D.; Harvey, V. M.; Haungs, A.; Hebbeker, T.; Heck, D.; Hill, G. C.;
Hojvat, C.; Hörandel, J.; Horvath, P.; Hrabovsky, M.; Huege, T.;
Insolia, A.; Isar, P. G.; Janecek, P.; Johnsen, J. A.; Juryšek, J.;
Kääpä, A.; Kampert, K. H.; Karastathis, N.; Keilhauer, B.; Kemp,
J.; Khakurdikar, A.; Kizakke Covilakam, V. V.; Klages, H.; Kleifges,
M.; Kleinfeller, J.; Köpke, M.; Kunka, N.; Lago, B. L.; Lang, R. G.;
Langner, N.; Leigui de Oliveira, M. A.; Lenok, V.; Letessier-Selvon,
A.; Lhenry-Yvon, I.; Lo Presti, D.; Lopes, L.; López, R.; Lu, L.;
Luce, Q.; Lundquist, J. P.; Machado Payeras, A.; Mancarella, G.;
Mandat, D.; Manning, B. C.; Manshanden, J.; Mantsch, P.; Marafico, S.;
Mariazzi, A.; Maris, I. C.; Marsella, G.; Martello, D.; Martinelli,
S.; Martínez Bravo, O.; Mastrodicasa, M.; Mathes, H. J.; Matthews,
J.; Matthiae, G.; Mayotte, E.; Mazur, P.; Medina-Tanco, G.; Melo,
D.; Menshikov, A.; Merenda, K. D.; Michal, S.; Micheletti, M. I.;
Miramonti, L.; Mollerach, S.; Montanet, F.; Morello, C.; Mostafa, M.;
Müller, A. L.; Muller, M. A.; Mulrey, K.; Mussa, R.; Muzio, M. S.;
Namasaka, W. M.; Nasr-Esfahani, A.; Nellen, L.; Niculescu-Oglinzanu,
M.; Niechciol, M.; Nitz, D.; Nosek, D.; Novotný, V.; Nozka, L.;
Nucita, A.; Nunez, L. A.; Palatka, M.; Pallotta, J.; Papenbreer, P.;
Parente, G.; Parra, A.; Pawlowsky, J.; Pech, M.; Pedreira, F.; Pękala,
J.; Pelayo, R.; Peña-Rodríguez, J.; Pereira Martins, E. E.; Perez
Armand, J.; Pérez Bertolli, C.; Perlin, M.; Perrone, L.; Petrera,
S.; Pierog, T.; Pimenta, M.; Pirronello, V.; Platino, M.; Pont, B.;
Pothast, M.; Privitera, P.; Prouza, M.; Puyleart, A.; Querchfeld,
S.; Rautenberg, J.; Ravignani, D.; Reininghaus, M.; Ridky, J.; Riehn,
F.; Risse, M.; Rizi, V.; Rodrigues de Carvalho, W.; Rodriguez Rojo,
J. R.; Roncoroni, M. J.; Rossoni, S.; Roth, M.; Roulet, E.; Rovero,
A.; Ruehl, P.; Saftoiu, A.; Salamida, F.; Salazar, H. I.; Salina,
G.; Sanabria Gomez, J.; Sánchez, F. A.; Santos, E. M.; Santos, E.;
Sarazin, F.; Sarmento, R.; Sarmiento-Cano, C.; Sato, R.; Savina, P.;
Schäfer, C. M.; Scherini, V.; Schieler, H.; Schimassek, M.; Schimp,
M.; Schlüter, F.; Schmidt, D.; Scholten, O.; Schovanek, P.; Schröder,
F. G.; Schröder, S.; Schulte, J.; Sciutto, S.; Scornavacche, M.;
Segreto, A.; Sehgal, S.; Shellard, R. C.; Sigl, G.; Silli, G.; Sima,
O.; Smida, R.; Sommers, P.; Soriano, J. F.; Souchard, J.; Squartini,
R.; Stadelmaier, M.; Stanca, D.; Stanič, S.; Stasielak, J.; Stassi,
P.; Streich, A.; Suárez-Durán, M.; Sudholz, T.; Suomijarvi, T.;
Supanitsky, A. D.; Szadkowski, Z.; Tapia, A.; Taricco, C.; Timmermans,
C.; Tkachenko, O.; Tobiska, P.; Todero Peixoto, C. J.; Tomé, B.;
Torrès, Z.; Travaini, A.; Travnicek, P.; Trimarelli, C.; Tueros, M.;
Ulrich, R.; Unger, M.; Vaclavek, L.; Vacula, M.; Valdés Galicia,
J. F.; Valore, L.; Varela, E.; Vásquez-Ramírez, A.; Veberic, D.;
Ventura, C.; Vergara Quispe, I. D.; Verzi, V.; Vicha, J.; Vink, J.;
Vorobiov, S.; Wahlberg, H.; Watanabe, C. K. O.; Watson, A.; Weber,
M.; Weindl, A.; Wiencke, L.; Wilczyński, H.; Wirtz, M.; Wittkowski,
D.; Wundheiler, B.; Yushkov, A.; Zapparrata, O.; Zas, E.; Zavrtanik,
D.; Zavrtanik, M.; Zehrer, L.
Bibcode: 2022icrc.confE.270F
Altcode: 2022PoS...395E.270F
No abstract at ADS
Title: Expected performance of the AugerPrime Radio Detector
Authors: Schlüter, F.; The Pierre Auger Collaboration; Abreu, P.;
Aglietta, M.; Albury, J. M.; Allekotte, I.; Almela, A.; Alvarez-Muniz,
J.; Alves Batista, R.; Anastasi, G. A.; Anchordoqui, L. A.; Andrada,
B.; Andringa, S.; Aramo, C.; Araújo Ferreira, P. R.; Arteaga
Velazquez, J. C.; Asorey, H. G.; Assis, P.; Avila, G.; Badescu,
A. M.; Bakalova, A.; Balaceanu, A.; Barbato, F.; Barreira Luz, R. J.;
Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou,
X.; Biermann, P. L.; Binet, V.; Bismark, K.; Bister, T.; Biteau,
J.; Blazek, J.; Bleve, C.; Bohacova, M.; Boncioli, D.; Bonifazi,
C.; Bonneau Arbeletche, L.; Borodai, N.; Botti, A. M.; Brack, J.;
Bretz, T.; Brichetto Orchera, P. G.; Briechle, F. L.; Buchholz, P.;
Bueno, A.; Buitink, S.; Buscemi, M.; Büsken, M.; Caballero-Mora,
K. S.; Caccianiga, L.; Canfora, F.; Caracas, I.; Carceller, J. M.;
Caruso, R.; Castellina, A.; Catalani, F.; Cataldi, G.; Cazon,
L.; Cerda, M.; Chinellato, J. A.; Chudoba, J.; Chytka, L.; Clay,
R. W.; Cobos Cerutti, A.; Colalillo, R.; Coleman, A.; Coluccia,
M. R.; Conceição, R.; Condorelli, A.; Consolati, G.; Contreras,
F.; Convenga, F.; Correia dos Santos, D.; Covault, C.; Dasso, S.;
Daumiller, K.; Dawson, B. R.; Day, J. A.; de Almeida, R. M.; de Jesús,
J.; de Jong, S. J.; De Mauro, G.; de Mello Neto, J.; De Mitri, I.;
de Oliveira, J.; de Oliveira Franco, D.; de Palma, F.; de Souza, V.;
De Vito, E.; del Río, M.; Deligny, O.; Deval, L.; di Matteo, A.;
Dobrigkeit, C.; D'Olivo, J. C.; Domingues Mendes, L. M.; dos Anjos,
R.; dos Santos, D.; Dova, M. T.; Ebr, J.; Engel, R.; Epicoco, I.;
Erdmann, M.; Escobar, C. O.; Etchegoyen, A.; Falcke, H.; Farmer, J.;
Farrar, G. R.; Fauth, A.; Fazzini, N.; Feldbusch, F.; Fenu, F.; Fick,
B.; Figueira, J. M.; Filipcic, A.; Fitoussi, T.; Fodran, T.; Freire,
M. M.; Fujii, T.; Fuster, A.; Galea, C.; Galelli, C.; García, B.;
García Vegas, A. L.; Gemmeke, H.; Gesualdi, F.; Gherghel-Lascu,
A.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Glombitza, J.; Gobbi,
F.; Gollan, F.; Golup, G.; Gómez Berisso, M.; Gómez Vitale, P. F.;
Gongora, J. P.; González, J. M.; Gonzalez, N. M.; Goos, I.; Gora,
D.; Gorgi, A.; Gottowik, M.; Grubb, T. D.; Guarino, F.; Guedes, G.;
Guido, E.; Hahn, S.; Hamal, P.; Hampel, M. R.; Hansen, P. M.; Harari,
D.; Harvey, V. M.; Haungs, A.; Hebbeker, T.; Heck, D.; Hill, G. C.;
Hojvat, C.; Hörandel, J.; Horvath, P.; Hrabovsky, M.; Huege, T.;
Insolia, A.; Isar, P. G.; Janecek, P.; Johnsen, J. A.; Juryšek, J.;
Kääpä, A.; Kampert, K. H.; Karastathis, N.; Keilhauer, B.; Kemp,
J.; Khakurdikar, A.; Kizakke Covilakam, V. V.; Klages, H.; Kleifges,
M.; Kleinfeller, J.; Köpke, M.; Kunka, N.; Lago, B. L.; Lang, R. G.;
Langner, N.; Leigui de Oliveira, M. A.; Lenok, V.; Letessier-Selvon,
A.; Lhenry-Yvon, I.; Lo Presti, D.; Lopes, L.; López, R.; Lu, L.;
Luce, Q.; Lundquist, J. P.; Machado Payeras, A.; Mancarella, G.;
Mandat, D.; Manning, B. C.; Manshanden, J.; Mantsch, P.; Marafico, S.;
Mariazzi, A.; Maris, I. C.; Marsella, G.; Martello, D.; Martinelli,
S.; Martínez Bravo, O.; Mastrodicasa, M.; Mathes, H. J.; Matthews,
J.; Matthiae, G.; Mayotte, E.; Mazur, P.; Medina-Tanco, G.; Melo,
D.; Menshikov, A.; Merenda, K. D.; Michal, S.; Micheletti, M. I.;
Miramonti, L.; Mollerach, S.; Montanet, F.; Morello, C.; Mostafa, M.;
Müller, A. L.; Muller, M. A.; Mulrey, K.; Mussa, R.; Muzio, M. S.;
Namasaka, W. M.; Nasr-Esfahani, A.; Nellen, L.; Niculescu-Oglinzanu,
M.; Niechciol, M.; Nitz, D.; Nosek, D.; Novotný, V.; Nozka, L.;
Nucita, A.; Nunez, L. A.; Palatka, M.; Pallotta, J.; Papenbreer, P.;
Parente, G.; Parra, A.; Pawlowsky, J.; Pech, M.; Pedreira, F.; Pękala,
J.; Pelayo, R.; Peña-Rodríguez, J.; Pereira Martins, E. E.; Perez
Armand, J.; Pérez Bertolli, C.; Perlin, M.; Perrone, L.; Petrera,
S.; Pierog, T.; Pimenta, M.; Pirronello, V.; Platino, M.; Pont, B.;
Pothast, M.; Privitera, P.; Prouza, M.; Puyleart, A.; Querchfeld,
S.; Rautenberg, J.; Ravignani, D.; Reininghaus, M.; Ridky, J.; Riehn,
F.; Risse, M.; Rizi, V.; Rodrigues de Carvalho, W.; Rodriguez Rojo,
J. R.; Roncoroni, M. J.; Rossoni, S.; Roth, M.; Roulet, E.; Rovero,
A.; Ruehl, P.; Saftoiu, A.; Salamida, F.; Salazar, H. I.; Salina,
G.; Sanabria Gomez, J.; Sánchez, F. A.; Santos, E. M.; Santos, E.;
Sarazin, F.; Sarmento, R.; Sarmiento-Cano, C.; Sato, R.; Savina,
P.; Schäfer, C. M.; Scherini, V.; Schieler, H.; Schimassek, M.;
Schimp, M.; Schmidt, D.; Scholten, O.; Schovanek, P.; Schröder, F. G.;
Schröder, S.; Schulte, J.; Sciutto, S.; Scornavacche, M.; Segreto, A.;
Sehgal, S.; Shellard, R. C.; Sigl, G.; Silli, G.; Sima, O.; Smida, R.;
Sommers, P.; Soriano, J. F.; Souchard, J.; Squartini, R.; Stadelmaier,
M.; Stanca, D.; Stanič, S.; Stasielak, J.; Stassi, P.; Streich, A.;
Suárez-Durán, M.; Sudholz, T.; Suomijarvi, T.; Supanitsky, A. D.;
Szadkowski, Z.; Tapia, A.; Taricco, C.; Timmermans, C.; Tkachenko, O.;
Tobiska, P.; Todero Peixoto, C. J.; Tomé, B.; Torrès, Z.; Travaini,
A.; Travnicek, P.; Trimarelli, C.; Tueros, M.; Ulrich, R.; Unger, M.;
Vaclavek, L.; Vacula, M.; Valdés Galicia, J. F.; Valore, L.; Varela,
E.; Vásquez-Ramírez, A.; Veberic, D.; Ventura, C.; Vergara Quispe,
I. D.; Verzi, V.; Vicha, J.; Vink, J.; Vorobiov, S.; Wahlberg, H.;
Watanabe, C. K. O.; Watson, A.; Weber, M.; Weindl, A.; Wiencke, L.;
Wilczyński, H.; Wirtz, M.; Wittkowski, D.; Wundheiler, B.; Yushkov,
A.; Zapparrata, O.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zehrer, L.
Bibcode: 2022icrc.confE.262S
Altcode: 2022PoS...395E.262S
No abstract at ADS
Title: On the need for unbiasing azimuthal asymmetries in signals
measured by surface detector arrays
Authors: Luce, Q.; Roth, M.; Schmidt, D.; Veberic, D.
Bibcode: 2022icrc.confE.435L
Altcode: 2022PoS...395E.435L
No abstract at ADS
Title: Neutron production in extensive air showers
Authors: Engel, R.; Ferrari, A.; Roth, M.; Schimassek, M.; Schmidt,
D.; Veberic, D.
Bibcode: 2022icrc.confE.492E
Altcode: 2022PoS...395E.492E
No abstract at ADS
Title: Sustainability in Astroparticle Physics
Authors: Grinberg, V.; Jahnke, K.; Lindenstruth, V.; Markou, C.;
Funk, S.; Katz, U.; Roth, M.
Bibcode: 2022icrc.confE1401G
Altcode: 2022PoS...395E1401G
No abstract at ADS
Title: The XY Scanner - A Versatile Method of the Absolute End-to-End
Calibration of Fluorescence Detectors
Authors: Schäfer, C. M.; The Pierre Auger Collaboration; Abreu, P.;
Aglietta, M.; Albury, J. M.; Allekotte, I.; Almela, A.; Alvarez-Muniz,
J.; Alves Batista, R.; Anastasi, G. A.; Anchordoqui, L. A.; Andrada,
B.; Andringa, S.; Aramo, C.; Araújo Ferreira, P. R.; Arteaga
Velazquez, J. C.; Asorey, H. G.; Assis, P.; Avila, G.; Badescu,
A. M.; Bakalova, A.; Balaceanu, A.; Barbato, F.; Barreira Luz, R. J.;
Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou,
X.; Biermann, P. L.; Binet, V.; Bismark, K.; Bister, T.; Biteau,
J.; Blazek, J.; Bleve, C.; Bohacova, M.; Boncioli, D.; Bonifazi,
C.; Bonneau Arbeletche, L.; Borodai, N.; Botti, A. M.; Brack, J.;
Bretz, T.; Brichetto Orchera, P. G.; Briechle, F. L.; Buchholz, P.;
Bueno, A.; Buitink, S.; Buscemi, M.; Büsken, M.; Caballero-Mora,
K. S.; Caccianiga, L.; Canfora, F.; Caracas, I.; Carceller, J. M.;
Caruso, R.; Castellina, A.; Catalani, F.; Cataldi, G.; Cazon,
L.; Cerda, M.; Chinellato, J. A.; Chudoba, J.; Chytka, L.; Clay,
R. W.; Cobos Cerutti, A.; Colalillo, R.; Coleman, A.; Coluccia,
M. R.; Conceição, R.; Condorelli, A.; Consolati, G.; Contreras,
F.; Convenga, F.; Correia dos Santos, D.; Covault, C.; Dasso, S.;
Daumiller, K.; Dawson, B. R.; Day, J. A.; de Almeida, R. M.; de Jesús,
J.; de Jong, S. J.; De Mauro, G.; de Mello Neto, J.; De Mitri, I.;
de Oliveira, J.; de Oliveira Franco, D.; de Palma, F.; de Souza, V.;
De Vito, E.; del Río, M.; Deligny, O.; Deval, L.; di Matteo, A.;
Dobrigkeit, C.; D'Olivo, J. C.; Domingues Mendes, L. M.; dos Anjos,
R.; dos Santos, D.; Dova, M. T.; Ebr, J.; Engel, R.; Epicoco, I.;
Erdmann, M.; Escobar, C. O.; Etchegoyen, A.; Falcke, H.; Farmer, J.;
Farrar, G. R.; Fauth, A.; Fazzini, N.; Feldbusch, F.; Fenu, F.; Fick,
B.; Figueira, J. M.; Filipcic, A.; Fitoussi, T.; Fodran, T.; Freire,
M. M.; Fujii, T.; Fuster, A.; Galea, C.; Galelli, C.; García, B.;
García Vegas, A. L.; Gemmeke, H.; Gesualdi, F.; Gherghel-Lascu,
A.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Glombitza, J.; Gobbi,
F.; Gollan, F.; Golup, G.; Gómez Berisso, M.; Gómez Vitale, P. F.;
Gongora, J. P.; González, J. M.; Gonzalez, N. M.; Goos, I.; Gora,
D.; Gorgi, A.; Gottowik, M.; Grubb, T. D.; Guarino, F.; Guedes, G.;
Guido, E.; Hahn, S.; Hamal, P.; Hampel, M. R.; Hansen, P. M.; Harari,
D.; Harvey, V. M.; Haungs, A.; Hebbeker, T.; Heck, D.; Hill, G. C.;
Hojvat, C.; Hörandel, J.; Horvath, P.; Hrabovsky, M.; Huege, T.;
Insolia, A.; Isar, P. G.; Janecek, P.; Johnsen, J. A.; Juryšek, J.;
Kääpä, A.; Kampert, K. H.; Karastathis, N.; Keilhauer, B.; Kemp,
J.; Khakurdikar, A.; Kizakke Covilakam, V. V.; Klages, H.; Kleifges,
M.; Kleinfeller, J.; Köpke, M.; Kunka, N.; Lago, B. L.; Lang, R. G.;
Langner, N.; Leigui de Oliveira, M. A.; Lenok, V.; Letessier-Selvon,
A.; Lhenry-Yvon, I.; Lo Presti, D.; Lopes, L.; López, R.; Lu, L.;
Luce, Q.; Lundquist, J. P.; Machado Payeras, A.; Mancarella, G.;
Mandat, D.; Manning, B. C.; Manshanden, J.; Mantsch, P.; Marafico, S.;
Mariazzi, A.; Maris, I. C.; Marsella, G.; Martello, D.; Martinelli,
S.; Martínez Bravo, O.; Mastrodicasa, M.; Mathes, H. J.; Matthews,
J.; Matthiae, G.; Mayotte, E.; Mazur, P.; Medina-Tanco, G.; Melo,
D.; Menshikov, A.; Merenda, K. D.; Michal, S.; Micheletti, M. I.;
Miramonti, L.; Mollerach, S.; Montanet, F.; Morello, C.; Mostafa, M.;
Müller, A. L.; Muller, M. A.; Mulrey, K.; Mussa, R.; Muzio, M. S.;
Namasaka, W. M.; Nasr-Esfahani, A.; Nellen, L.; Niculescu-Oglinzanu,
M.; Niechciol, M.; Nitz, D.; Nosek, D.; Novotný, V.; Nozka, L.;
Nucita, A.; Nunez, L. A.; Palatka, M.; Pallotta, J.; Papenbreer, P.;
Parente, G.; Parra, A.; Pawlowsky, J.; Pech, M.; Pedreira, F.; Pękala,
J.; Pelayo, R.; Peña-Rodríguez, J.; Pereira Martins, E. E.; Perez
Armand, J.; Pérez Bertolli, C.; Perlin, M.; Perrone, L.; Petrera,
S.; Pierog, T.; Pimenta, M.; Pirronello, V.; Platino, M.; Pont, B.;
Pothast, M.; Privitera, P.; Prouza, M.; Puyleart, A.; Querchfeld,
S.; Rautenberg, J.; Ravignani, D.; Reininghaus, M.; Ridky, J.; Riehn,
F.; Risse, M.; Rizi, V.; Rodrigues de Carvalho, W.; Rodriguez Rojo,
J. R.; Roncoroni, M. J.; Rossoni, S.; Roth, M.; Roulet, E.; Rovero,
A.; Ruehl, P.; Saftoiu, A.; Salamida, F.; Salazar, H. I.; Salina,
G.; Sanabria Gomez, J.; Sánchez, F. A.; Santos, E. M.; Santos, E.;
Sarazin, F.; Sarmento, R.; Sarmiento-Cano, C.; Sato, R.; Savina, P.;
Scherini, V.; Schieler, H.; Schimassek, M.; Schimp, M.; Schlüter, F.;
Schmidt, D.; Scholten, O.; Schovanek, P.; Schröder, F. G.; Schröder,
S.; Schulte, J.; Sciutto, S.; Scornavacche, M.; Segreto, A.; Sehgal,
S.; Shellard, R. C.; Sigl, G.; Silli, G.; Sima, O.; Smida, R.; Sommers,
P.; Soriano, J. F.; Souchard, J.; Squartini, R.; Stadelmaier, M.;
Stanca, D.; Stanič, S.; Stasielak, J.; Stassi, P.; Streich, A.;
Suárez-Durán, M.; Sudholz, T.; Suomijarvi, T.; Supanitsky, A. D.;
Szadkowski, Z.; Tapia, A.; Taricco, C.; Timmermans, C.; Tkachenko, O.;
Tobiska, P.; Todero Peixoto, C. J.; Tomé, B.; Torrès, Z.; Travaini,
A.; Travnicek, P.; Trimarelli, C.; Tueros, M.; Ulrich, R.; Unger, M.;
Vaclavek, L.; Vacula, M.; Valdés Galicia, J. F.; Valore, L.; Varela,
E.; Vásquez-Ramírez, A.; Veberic, D.; Ventura, C.; Vergara Quispe,
I. D.; Verzi, V.; Vicha, J.; Vink, J.; Vorobiov, S.; Wahlberg, H.;
Watanabe, C. K. O.; Watson, A.; Weber, M.; Weindl, A.; Wiencke, L.;
Wilczyński, H.; Wirtz, M.; Wittkowski, D.; Wundheiler, B.; Yushkov,
A.; Zapparrata, O.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zehrer, L.
Bibcode: 2022icrc.confE.220S
Altcode: 2022PoS...395E.220S
No abstract at ADS
Title: On Strengthening of the Solar f-mode Prior to Active Region
Emergence Using the Fourier-Hankel Analysis
Authors: Waidele, Matthias; Roth, Markus; Singh, Nishant; Käpylä,
Petri
Bibcode: 2022arXiv220211236W
Altcode:
Recent results of Singh et al. (2016) show that the emergence of an
active region (AR) can be seen in a strengthening of the f-mode power
up to two days prior of the region's formation. In the original work,
ring diagram analysis was used to estimate the power evolution. In this
study, we make use of the Fourier-Hankel method, essentially testing
the aforementioned results with an independent method. The data is
acquired from SDO/HMI, studying the ARs 11158, 11072, 11105, 11130,
11242 and 11768. Investigating the total power as a function of time,
we find a similar behavior to the original work, which is an enhancement
of f-mode power about one to three days prior to AR emergence. Analysis
of the absorption coefficient $\alpha$, yielded by a Fourier-Hankel
analysis, shows neither absorption ($\alpha > 0$) nor emission
($\alpha < 0$) of power during the enhancement. Finding no changes
of the absorption coefficient (i.e. $\alpha = 0$) is an important
result, as it narrows down the possible physical interpretation of
the original f-mode power enhancement, showing that no directional
dependence (in the sense of inward and outward moving waves) is present.
Title: Urban Water Storage Capacity Inferred From Observed
Evapotranspiration Recession
Authors: Jongen, H. J.; Steeneveld, G. J.; Beringer, J.; Christen,
A.; Chrysoulakis, N.; Fortuniak, K.; Hong, J.; Hong, J. W.; Jacobs,
C. M. J.; Järvi, L.; Meier, F.; Pawlak, W.; Roth, M.; Theeuwes,
N. E.; Velasco, E.; Vogt, R.; Teuling, A. J.
Bibcode: 2022GeoRL..4996069J
Altcode:
Water storage plays an important role in mitigating heat and flooding
in urban areas. Assessment of the water storage capacity of cities
remains challenging due to the inherent heterogeneity of the urban
surface. Traditionally, effective storage has been estimated from
runoff. Here, we present a novel approach to estimate effective
water storage capacity from recession rates of observed evaporation
during precipitation-free periods. We test this approach for cities
at neighborhood scale with eddy-covariance based latent heat flux
observations from 14 contrasting sites with different local climate
zones, vegetation cover and characteristics, and climates. Based on
analysis of 583 drydowns, we find storage capacities to vary between
1.3 and 28.4 mm, corresponding to e-folding timescales of 1.8-20.1
days. This makes the urban storage capacity at least five times smaller
than all the observed values for natural ecosystems, reflecting an
evaporation regime characterized by extreme water limitation.
Title: Absorption of High-frequency Oscillations and Its Relation
to Emissivity Reduction
Authors: Waidele, Matthias; Roth, Markus; Vigeesh, Gangadharan;
Glogowski, Kolja
Bibcode: 2021ApJ...913..108W
Altcode: 2021arXiv210601745W
Sunspots are known to be strong absorbers of solar oscillation
modal power. The most convincing way to demonstrate this is done via
Fourier-Hankel decomposition (FHD), where the local oscillation field
is separated into in- and outgoing waves, showing the reduction in
power. Due to the Helioseismic and Magnetic Imager's high-cadence
Doppler measurements, power absorption can be investigated at
frequencies beyond the acoustic cutoff frequency. We perform an
FHD on five sunspot regions and two quiet-Sun control regions
and study the resulting absorption spectra αℓ(ν),
specifically at frequencies ν > 5.3 mHz. We observe an unreported
high-frequency absorption feature, which only appears in the presence of
a sunspot. This feature is confined to phase speeds of one-skip waves
whose origins coincide with the sunspot's center, with vph
= 85.7 km s-1 in this case. By employing a fit to the
absorption spectra at a constant phase speed, we find that the peak
absorption strength ${\alpha }_{\max }$ lies between 0.166 and 0.222
at a noise level of about 0.009 (5%). The well-known absorption
along ridges at lower frequencies can reach up to ${\alpha }_{\max
}\approx 0.5$ . Thus our finding in the absorption spectrum is weaker,
but nevertheless significant. From first considerations regarding the
energy budget of high-frequency waves, this observation can likely be
explained by the reduction of emissivity within the sunspot. We derive
a simple relation between emissivity and absorption. We conclude that
sunspots yield a wave power absorption signature (for certain phase
speeds only), which may help in understanding the effect of strong
magnetic fields on convection and source excitation and potentially
in understanding the general sunspot subsurface structure.
Title: Editorial: The Future of Asteroseismology
Authors: Guzik, Joyce Ann; Roth, Markus
Bibcode: 2021FrASS...8...97G
Altcode:
No abstract at ADS
Title: Kink instability of triangular jets in the solar atmosphere
Authors: Zaqarashvili, T. V.; Lomineishvili, S.; Leitner, P.;
Hanslmeier, A.; Gömöry, P.; Roth, M.
Bibcode: 2021A&A...649A.179Z
Altcode: 2021arXiv210209952Z
Context. It is known that hydrodynamic triangular jets (i.e. the
jet with maximal velocity at its axis, which linearly decreases at
both sides) are unstable to anti-symmetric kink perturbations. The
inclusion of the magnetic field may lead to the stabilisation of the
jets. Jets and complex magnetic fields are ubiquitous in the solar
atmosphere, which suggests the possibility of the kink instability in
certain cases.
Aims: The aim of the paper is to study the kink
instability of triangular jets sandwiched between magnetic tubes (or
slabs) and its possible connection to observed properties of the jets in
the solar atmosphere.
Methods: A dispersion equation governing
the kink perturbations is obtained through matching of analytical
solutions at the jet boundaries. The equation is solved analytically
and numerically for different parameters of jets and surrounding
plasma. The analytical solution is accompanied by a numerical simulation
of fully non-linear magnetohydrodynamic (MHD) equations for a particular
situation of solar type II spicules.
Results: Magnetohydrodynamic
triangular jets are unstable to the dynamic kink instability depending
on the Alfvén Mach number (the ratio of flow to Alfvén speeds) and
the ratio of internal and external densities. When the jet has the
same density as the surrounding plasma, only super-Alfvénic flows are
unstable. However, denser jets are also unstable in a sub-Alfvénic
regime. Jets with an angle to the ambient magnetic field have much
lower thresholds of instability than field-aligned flows. Growth
times of the kink instability are estimated to be 6−15 min for type
I spicules and 5−60 s for type II spicules matching with their
observed lifetimes. The numerical simulation of full non-linear
equations shows that the transverse kink pulse locally destroys
the jet in less than a minute in type II spicule conditions.
Conclusions: Dynamic kink instability may lead to the full breakdown
of MHD flows and consequently to an observed disappearance of
spicules. Movies associated to Fig. 9 are available at https://www.aanda.org
Title: On the influence of magnetic topology on the propagation of
internal gravity waves in the solar atmosphere
Authors: Vigeesh, G.; Roth, M.; Steiner, O.; Fleck, B.
Bibcode: 2021RSPTA.37900177V
Altcode: 2020arXiv201006926V
The solar surface is a continuous source of internal gravity waves
(IGWs). IGWs are believed to supply the bulk of the wave energy for
the lower solar atmosphere, but their existence and role for the energy
balance of the upper layers is still unclear, largely due to the lack
of knowledge about the influence of the Sun's magnetic fields on
their propagation. In this work, we look at naturally excited IGWs
in realistic models of the solar atmosphere and study the effect
of different magnetic field topographies on their propagation. We
carry out radiation-magnetohydrodynamic simulations of a magnetic
field free and two magnetic models-one with an initial, homogeneous,
vertical field of 100 G magnetic flux density and one with an initial
horizontal field of 100 G flux density. The propagation properties
of IGWs are studied by examining the phase-difference and coherence
spectra in the kh - ω diagnostic diagram. We find that IGWs
in the upper solar atmosphere show upward propagation in the model with
predominantly horizontal field similar to the model without magnetic
field. In contrast to that the model with predominantly vertical fields
show downward propagation. This crucial difference in the propagation
direction is also revealed in the difference in energy transported by
waves for heights below 0.8 Mm. Higher up, the propagation properties
show a peculiar behaviour, which require further study. Our analysis
suggests that IGWs may play a significant role in the heating of
the chromospheric layers of the internetwork region where horizontal
fields are thought to be prevalent. This article is part of the
Theo Murphy meeting issue `High-resolution wave dynamics in the lower
solar atmosphere'.
Title: Improving PNLF Distance Measures with MUSE
Authors: Chase, O.; Roth, M.; Jacoby, G.; Ciardullo, R.; Davis, B.;
Weilbacher, P.
Bibcode: 2021AAS...23715414C
Altcode:
The tension between the Hubble Constant derived from the distance
ladder and that inferred from the early Universe has revitalized
efforts to measure precise distances to galaxies in the Local
Universe. Consequently, we have begun a program of using the ESO Multi
Unit Spectroscopic Explorer (MUSE) integral-field unit spectrograph
to measure [O III] 5007A Planetary Nebula Luminosity Function (PNLF)
distances to galaxies as far away as ~ 50 Mpc. This would be more than
twice the distance of any previous narrow-band PNLF measurement. In
this initial investigation, we use archival MUSE data to measure the
distances to 8 early-type galaxies between ~15 Mpc and ~30 Mpc using
PN sample sizes between ~15 and ~150. We construct difference images
in wavelength slices surrounding the [OIII] 5007A line, identify the
PN, measure their [O III] line fluxes, and pay special attention to
system uncertainties such as point-source aperture correction. Our
goal is to demonstrate the accuracy of MUSE data for deriving PNLF
distances in hopes of using the instrument to obtain a highly accurate
and independent measurement of the Hubble Constant.
Title: The Solar Orbiter Science Activity Plan. Translating solar
and heliospheric physics questions into action
Authors: Zouganelis, I.; De Groof, A.; Walsh, A. P.; Williams, D. R.;
Müller, D.; St Cyr, O. C.; Auchère, F.; Berghmans, D.; Fludra,
A.; Horbury, T. S.; Howard, R. A.; Krucker, S.; Maksimovic, M.;
Owen, C. J.; Rodríguez-Pacheco, J.; Romoli, M.; Solanki, S. K.;
Watson, C.; Sanchez, L.; Lefort, J.; Osuna, P.; Gilbert, H. R.;
Nieves-Chinchilla, T.; Abbo, L.; Alexandrova, O.; Anastasiadis, A.;
Andretta, V.; Antonucci, E.; Appourchaux, T.; Aran, A.; Arge, C. N.;
Aulanier, G.; Baker, D.; Bale, S. D.; Battaglia, M.; Bellot Rubio,
L.; Bemporad, A.; Berthomier, M.; Bocchialini, K.; Bonnin, X.; Brun,
A. S.; Bruno, R.; Buchlin, E.; Büchner, J.; Bucik, R.; Carcaboso,
F.; Carr, R.; Carrasco-Blázquez, I.; Cecconi, B.; Cernuda Cangas, I.;
Chen, C. H. K.; Chitta, L. P.; Chust, T.; Dalmasse, K.; D'Amicis, R.;
Da Deppo, V.; De Marco, R.; Dolei, S.; Dolla, L.; Dudok de Wit, T.;
van Driel-Gesztelyi, L.; Eastwood, J. P.; Espinosa Lara, F.; Etesi,
L.; Fedorov, A.; Félix-Redondo, F.; Fineschi, S.; Fleck, B.; Fontaine,
D.; Fox, N. J.; Gandorfer, A.; Génot, V.; Georgoulis, M. K.; Gissot,
S.; Giunta, A.; Gizon, L.; Gómez-Herrero, R.; Gontikakis, C.; Graham,
G.; Green, L.; Grundy, T.; Haberreiter, M.; Harra, L. K.; Hassler,
D. M.; Hirzberger, J.; Ho, G. C.; Hurford, G.; Innes, D.; Issautier,
K.; James, A. W.; Janitzek, N.; Janvier, M.; Jeffrey, N.; Jenkins,
J.; Khotyaintsev, Y.; Klein, K. -L.; Kontar, E. P.; Kontogiannis,
I.; Krafft, C.; Krasnoselskikh, V.; Kretzschmar, M.; Labrosse, N.;
Lagg, A.; Landini, F.; Lavraud, B.; Leon, I.; Lepri, S. T.; Lewis,
G. R.; Liewer, P.; Linker, J.; Livi, S.; Long, D. M.; Louarn, P.;
Malandraki, O.; Maloney, S.; Martinez-Pillet, V.; Martinovic, M.;
Masson, A.; Matthews, S.; Matteini, L.; Meyer-Vernet, N.; Moraitis,
K.; Morton, R. J.; Musset, S.; Nicolaou, G.; Nindos, A.; O'Brien,
H.; Orozco Suarez, D.; Owens, M.; Pancrazzi, M.; Papaioannou, A.;
Parenti, S.; Pariat, E.; Patsourakos, S.; Perrone, D.; Peter, H.;
Pinto, R. F.; Plainaki, C.; Plettemeier, D.; Plunkett, S. P.; Raines,
J. M.; Raouafi, N.; Reid, H.; Retino, A.; Rezeau, L.; Rochus, P.;
Rodriguez, L.; Rodriguez-Garcia, L.; Roth, M.; Rouillard, A. P.;
Sahraoui, F.; Sasso, C.; Schou, J.; Schühle, U.; Sorriso-Valvo, L.;
Soucek, J.; Spadaro, D.; Stangalini, M.; Stansby, D.; Steller, M.;
Strugarek, A.; Štverák, Š.; Susino, R.; Telloni, D.; Terasa, C.;
Teriaca, L.; Toledo-Redondo, S.; del Toro Iniesta, J. C.; Tsiropoula,
G.; Tsounis, A.; Tziotziou, K.; Valentini, F.; Vaivads, A.; Vecchio,
A.; Velli, M.; Verbeeck, C.; Verdini, A.; Verscharen, D.; Vilmer, N.;
Vourlidas, A.; Wicks, R.; Wimmer-Schweingruber, R. F.; Wiegelmann,
T.; Young, P. R.; Zhukov, A. N.
Bibcode: 2020A&A...642A...3Z
Altcode: 2020arXiv200910772Z
Solar Orbiter is the first space mission observing the solar plasma
both in situ and remotely, from a close distance, in and out of the
ecliptic. The ultimate goal is to understand how the Sun produces
and controls the heliosphere, filling the Solar System and driving
the planetary environments. With six remote-sensing and four in-situ
instrument suites, the coordination and planning of the operations are
essential to address the following four top-level science questions:
(1) What drives the solar wind and where does the coronal magnetic field
originate?; (2) How do solar transients drive heliospheric variability?;
(3) How do solar eruptions produce energetic particle radiation that
fills the heliosphere?; (4) How does the solar dynamo work and drive
connections between the Sun and the heliosphere? Maximising the
mission's science return requires considering the characteristics
of each orbit, including the relative position of the spacecraft
to Earth (affecting downlink rates), trajectory events (such
as gravitational assist manoeuvres), and the phase of the solar
activity cycle. Furthermore, since each orbit's science telemetry
will be downloaded over the course of the following orbit, science
operations must be planned at mission level, rather than at the level
of individual orbits. It is important to explore the way in which those
science questions are translated into an actual plan of observations
that fits into the mission, thus ensuring that no opportunities are
missed. First, the overarching goals are broken down into specific,
answerable questions along with the required observations and the
so-called Science Activity Plan (SAP) is developed to achieve this. The
SAP groups objectives that require similar observations into Solar
Orbiter Observing Plans, resulting in a strategic, top-level view of
the optimal opportunities for science observations during the mission
lifetime. This allows for all four mission goals to be addressed. In
this paper, we introduce Solar Orbiter's SAP through a series of
examples and the strategy being followed.
Title: On the detectability of large-scale flows by asteroseismology
Authors: Roth, Markus; Herzberg, Wiebke
Bibcode: 2020FrASS...7...68R
Altcode:
Large-scale convective motions are an integral part of stellar
interior dynamics and might play a relevant role in stellar
dynamo processes. However, they are difficult to detect or
characterize. Stellar oscillations are affected by convective flows due
to advection. For the Sun, forward calculations of the advective effect
of flows on oscillation modes have already been conducted, but the
effect has not yet been examined for other types of stars. Suitable
candidates are subgiant or red giant stars, since they possess
extensive outer convection zones, which likely feature large-scale
flow cells with strong flow velocities. We investigate the effects of
large-scale flows on oscillation modes of subgiant stars by means of
forward calculations based on an exemplary subgiant stellar model. We
focus in particular on non-axisymmetric cell formations, also referred
to as giant cells. The effects are described in the non-rotating and
the rotating case. By solving the forward problem, we evaluate, if
large-scale flow cells lead to signatures in asteroseismic data that
are suitable for the detection of such flows. The influence of flows is
calculated by employing perturbation theory as proposed by Lavely &
Ritzwoller (1992), where the flow is treated as a perturbation of a 1D
equilibrium stellar model. The presence of a flow leads to a coupling
of the modes, which results in frequency shifts and a mixing of the
mode eigenfunctions. For a non-rotating star, non-axisymmetric flows
lead to degeneracies between coupling modes, which cause an asymmetry
in the frequency shifts of modes of opposite azimuthal order. If
rotation is included, the degeneracy is lifted in first order, but
residual degenerate coupling and third order effects can still lead to
asymmetries, depending on whether the modes are of p- or of g-type. For
rotating stars, the mode mixing induced by non-axisymmetric flows causes
the observational signal of a perturbed mode to be multiperiodic,
which becomes visible in the power spectrum. An expression for the
amplitudes of the signal's different components is derived.
Title: Inference of Solar Rotation from Perturbations of Acoustic
Mode Eigenfunctions
Authors: Schad, Ariane; Roth, Markus
Bibcode: 2020ApJ...890...32S
Altcode: 2020arXiv200206114S
Today's picture of the internal solar rotation rate profile results
essentially from helioseismic analyses of frequency splittings
of resonant acoustic waves. Here we present another, complementary
estimation of the internal solar rotation rate using the perturbation of
the shape of the acoustic waves. For this purpose, we extend a global
helioseismic approach developed previously for the investigation of
the meridional flow to work on the components of the differential
rotation. We discuss the effect of rotation on mode eigenfunctions
and the observables based thereon. Based on a numerical study
using a simulated rotation rate profile, we tailor an inversion
approach and also consider the case of the presence of an additional
meridional flow. This inversion approach is then applied to data from
the Michelson Doppler Imager (MDI) on board the Solar Heliospheric
Observatory and the Helioseismic and Magnetic Imager (HMI) on board
the Solar Dynamics Observatory. In the end, rotation rate profiles
estimated from eigenfunction perturbation and frequency splittings
are compared. The rotation rate profiles from the two different
approaches are qualitatively in good agreement, especially for the
MDI data. Significant differences are obtained at high latitudes
>50° and near the subsurface. The result from HMI data shows
larger discrepancies between the different methods. We find that the
two global helioseismic approaches provide complementary methods for
measuring the solar rotation. Comparing the results from different
methods may help to reveal systematic influences that affect analyses
based on eigenfunction perturbations, like meridional flow measurements.
Title: Investigation of Surface Effects of Simple Flux Tubes Using
Numerical Simulations
Authors: Waidele, M.; Roth, M.
Bibcode: 2020ApJ...889...83W
Altcode: 2020arXiv200111798W
We use the SPARC code for MHD simulations with monolithic flux tubes of
varying subsurface topology. Our studies involve the interactions of
waves caused by a single source with subsurface magnetic fields. Mode
conversion causing acoustic power to trickle downwards along the
flux tube has been described before and can be visualized in our
simulations. We show that this downward propagation causes the flux tube
to act as an isolated source, creating a characteristic surface wave
field. Measuring this wave field at the surface reveals subsurface
properties of the magnetic field topology. Using time-distance
helioseismology, we demonstrate how to detect such a flux tube signal
based on a group travel time delay of Δt = 282.6 s due to the wave
packet spending time subsurface as a slow mode wave. Although the
amplitude is small and generally superimposed by the full wave field,
it can be detected if assumptions about Δt are made. We demonstrate
this for a simulation with solar-like sources. This kind of study has
the potential to reveal subsurface information of sunspots based on
the analysis of a surface signal.
Title: A Future Path for Solar Synoptic Ground-Based Observations
Authors: Roth, Markus
Bibcode: 2020ASSP...57..291R
Altcode:
This contribution provides a status overview on the work on the Solar
Physics Research Integrated Network Group (SPRING), which is a study
for a new ground-based network for future synoptic observations
of the Sun. The planning of this started together with Michael
J. Thompson. He strongly pushed for its realization. Several steps
were already completed: The science requirements were defined, and a
technical feasibility concept was completed in 2017. Based on this,
work is ongoing towards a preliminary design.
Title: Synthetic observations of internal gravity waves in the
solar atmosphere
Authors: Vigeesh, G.; Roth, M.
Bibcode: 2020A&A...633A.140V
Altcode: 2019arXiv191206435V
Aims: We study the properties of internal gravity waves (IGWs)
detected in synthetic observations that are obtained from realistic
numerical simulation of the solar atmosphere.
Methods: We
used four different simulations of the solar magneto-convection
performed using the CO5BOLD code. A magnetic-field-free
model and three magnetic models were simulated. The latter three
models start with an initial vertical, homogeneous field of 10, 50,
and 100 G magnetic flux density, representing different regions of
the quiet solar surface. We used the NICOLE code to compute synthetic
spectral maps from all the simulated models for the two magnetically
insensitive neutral iron lines Fe I λλ 5434 Å and 5576 Å. We
carried out Fourier analyses of the intensity and Doppler velocities
to derive the power, phase, and coherence in the kh -
ω diagnostic diagram to study the properties of internal gravity
waves.
Results: We find the signatures of the internal gravity
waves in the synthetic spectra to be consistent with observations
of the real Sun. The effect of magnetic field on the wave spectra is
not as clearly discernible in synthetic observations as in the case of
numerical simulations. The phase differences obtained using the spectral
lines are significantly different from the phase differences in the
simulation. The phase coherency between two atmospheric layers in the
gravity wave regime is height dependent and is seen to decrease with
the travel distance between the observed layers. In the studied models,
the lower atmosphere shows a phase coherency above the significance
level for a height separation of ∼400 km, while in the chromospheric
layers it reduces to ∼100-200 km depending on the average magnetic
flux density. Conclusion. We conclude that the energy flux of IGWs
determined from the phase difference analysis may be overestimated
by an order of magnitude. Spectral lines that are weak and less
temperature sensitive may be better suited to detecting internal waves
and accurately determining their energy flux in the solar atmosphere.
Title: Frequency Distribution of Acoustic Oscillation in the Solar
Atmosphere During Flare Event
Authors: Wiśniewska, A.; Chmielewska, E.; Radziszewski, K.; Roth,
M.; Staiger, J.
Bibcode: 2019ApJ...886...32W
Altcode: 2022arXiv220302420W
We present a study of multi-wavelength observations, of a C 2.3 solar
flare in Active Region NOAA 12353, observed on 2015 May 23, which
reveal new properties of acoustic waves in the flaring region. The
space-, and ground-based data measured by the HELioseismological
Large Regions Interferometric Device, operating at the Vacuum Tower
Telescope, the Atmospheric Imaging Assembly (AIA), and Helioseismic
and Magnetic Imager on board the Solar Dynamic Observatory, were used
in this paper. First, using power spectra of solar oscillations,
we identified the dominant frequencies and their location at seven
different atmospheric levels before and after the flare event. Second,
based on AIA observations taken in six Extreme Ultraviolet filters, we
derived Differential Emission Measure (DEM) profiles and DEM maps of the
flare. Finally, we confirm the sigma shape of the magnetic field in the
active area, directly related to the flare. Our results are as follows:
the high-frequency waves (ν > 5 mHz) in the photosphere, in both
cases, before and after the flare, are generated at the footpoints of
the chromospheric loop, while in the chromosphere (Hα line), before
the event the power enhancement exhibits the maximum of flare emission,
and after the eruption the enhancement by all frequencies is observed
only in the post-flare loop area. Moreover, the power of oscillation in
the pores surrounding the area before the flare has a random character,
while after the flare oscillation power is concentrated in the pore,
and weakened outside of. We conclude that accurate detection of
high-frequency acoustic waves in active regions can lead to faster
and easier prediction of high-energy events.
Title: ngGONG: The Next Generation GONG - A New Solar Synoptic
Observational Network
Authors: Hill, Frank; Hammel, Heidi; Martinez-Pillet, Valentin; de
Wijn, A.; Gosain, S.; Burkepile, J.; Henney, C. J.; McAteer, J.; Bain,
H. M.; Manchester, W.; Lin, H.; Roth, M.; Ichimoto, K.; Suematsu, Y.
Bibcode: 2019BAAS...51g..74H
Altcode: 2019astro2020U..74H
The white paper describes a next-generation GONG, a ground-based
geographically distributed network of instrumentation to continually
observe the Sun. This would provide data for solar magnetic field
research and space weather forecasting, and would extend the time
coverage of helioseismology.
Title: Kilotesla plasmoid formation by a trapped relativistic
laser beam
Authors: Ehret, M.; Kochetkov, Yu.; Abe, Y.; Law, K. F. F.;
Stepanischev, V.; Fujioka, S.; d'Humi'eres, E.; Zielbauer, B.;
Bagnoud, V.; Schaumann, G.; Roth, M.; Tikhonchuk, V.; Santos, J. J.;
Korneev, Ph.
Bibcode: 2019arXiv190811430E
Altcode:
A strong quasi-stationary magnetic field is generated in hollow targets
with curved internal surface under the action of a relativistically
intense picosecond laser pulse. Experimental data evidence formation
of quasistationary strongly magnetized plasma structures decaying
on the hundred picoseconds time scale, with the maximum value of
magnetic field strength of the kilotesla scale. Numerical simulations
unravel the importance of transient processes during the magnetic
field generation, and suggest the existence of fast and slow regimes
of plasmoid evolution depending on the interaction parameters. The
principal setup is universal for perspective highly magnetized plasma
application and fundamental studies.
Title: Search for dark photons as candidates for Dark Matter with FUNK
Authors: Andrianavalomahefa, A.; Daumiller, K.; Engel, R.; Döbrich,
B.; Jaeckel, J.; Kowalski, M.; Lindner, A.; Mathes, H. J.; Redondo,
J.; Roth, M.; Schwetz, T.; Schäfer, C. M.; Ulrich, R.; Veberic, D.
Bibcode: 2019ICRC...36..517A
Altcode: 2019PoS...358..517A
No abstract at ADS
Title: A Muon-based Observable to Detect Photons at Ultra-high
Energies
Authors: Gonzalez, N. M.; Sánchez, F. A.; Roth, M.; Etchegoyen, A.
Bibcode: 2019ICRC...36..271G
Altcode: 2019PoS...358..271G
No abstract at ADS
Title: Synoptic Studies of the Sun as a Key to Understanding Stellar
Astrospheres
Authors: Martinez Pillet, Valentin; Hill, Frank; Hammel, Heidi B.;
de Wijn, Alfred G.; Gosain, Sanjay; Burkepile, Joan; Henney, Carl;
McAteer, R. T. James; Bain, Hazel; Manchester, Ward; Lin, Haosheng;
Roth, Markus; Ichimoto, Kiyoshi; Suematsu, Yoshinori
Bibcode: 2019BAAS...51c.110M
Altcode: 2019astro2020T.110M; 2019arXiv190306944M
Ground-based solar observations provide key contextual data (i.e., the
"big picture") to produce a complete description of the only astrosphere
we can study in situ: our Sun's heliosphere. This white paper outlines
the current paradigm for ground-based solar synoptic observations,
and indicates those areas that will benefit from focused attention.
Title: Internal Gravity Waves in the Magnetized Solar
Atmosphere. II. Energy Transport
Authors: Vigeesh, G.; Roth, M.; Steiner, O.; Jackiewicz, J.
Bibcode: 2019ApJ...872..166V
Altcode: 2019arXiv190108871V
In this second paper of the series on internal gravity waves (IGWs),
we present a study of the generation and propagation of IGWs in a
model solar atmosphere with diverse magnetic conditions. A magnetic
field-free and three magnetic models that start with an initial,
vertical, homogeneous field of 10, 50, and 100 G magnetic flux density,
are simulated using the CO5BOLD code. We find that the
IGWs are generated in similar manner in all four models in spite of
the differences in the magnetic environment. The mechanical energy
carried by IGWs is significantly larger than that of the acoustic
waves in the lower part of the atmosphere, making them an important
component of the total wave energy budget. The mechanical energy flux
(106-103 W m-2) is a few orders of
magnitude larger than the Poynting flux (103-101
W m-2). The Poynting fluxes show a downward component in
the frequency range corresponding to the IGWs, which confirm that
these waves do not propagate upward in the atmosphere when the fields
are predominantly vertical and strong. We conclude that, in the upper
photosphere, the propagation properties of IGWs depend on the average
magnetic field strength and therefore these waves can be potential
candidates for magnetic field diagnostics of these layers. However,
their subsequent coupling to Alfvénic waves is unlikely in a magnetic
environment permeated with predominantly vertical fields, and therefore
they may not directly or indirectly contribute to the heating of layers
above plasma-β less than 1.
Title: Carnegie Supernova Project-II: The Near-infrared Spectroscopy
Program
Authors: Hsiao, E. Y.; Phillips, M. M.; Marion, G. H.; Kirshner,
R. P.; Morrell, N.; Sand, D. J.; Burns, C. R.; Contreras, C.;
Hoeflich, P.; Stritzinger, M. D.; Valenti, S.; Anderson, J. P.;
Ashall, C.; Baltay, C.; Baron, E.; Banerjee, D. P. K.; Davis, S.;
Diamond, T. R.; Folatelli, G.; Freedman, Wendy L.; Förster, F.;
Galbany, L.; Gall, C.; González-Gaitán, S.; Goobar, A.; Hamuy, M.;
Holmbo, S.; Kasliwal, M. M.; Krisciunas, K.; Kumar, S.; Lidman, C.;
Lu, J.; Nugent, P. E.; Perlmutter, S.; Persson, S. E.; Piro, A. L.;
Rabinowitz, D.; Roth, M.; Ryder, S. D.; Schmidt, B. P.; Shahbandeh,
M.; Suntzeff, N. B.; Taddia, F.; Uddin, S.; Wang, L.
Bibcode: 2019PASP..131a4002H
Altcode: 2018arXiv181008213H
Shifting the focus of Type Ia supernova (SN Ia) cosmology to the near
infrared (NIR) is a promising way to significantly reduce the systematic
errors, as the strategy minimizes our reliance on the empirical
width-luminosity relation and uncertain dust laws. Observations in the
NIR are also crucial for our understanding of the origins and evolution
of these events, further improving their cosmological utility. Any
future experiments in the rest-frame NIR will require knowledge of the
SN Ia NIR spectroscopic diversity, which is currently based on a small
sample of observed spectra. Along with the accompanying paper, Phillips
et al., we introduce the Carnegie Supernova Project-II (CSP-II), to
follow-up nearby SNe Ia in both the optical and the NIR. In particular,
this paper focuses on the CSP-II NIR spectroscopy program, describing
the survey strategy, instrumental setups, data reduction, sample
characteristics, and future analyses on the data set. In collaboration
with the Harvard-Smithsonian Center for Astrophysics (CfA) Supernova
Group, we obtained 661 NIR spectra of 157 SNe Ia. Within this sample,
451 NIR spectra of 90 SNe Ia have corresponding CSP-II follow-up
light curves. Such a sample will allow detailed studies of the NIR
spectroscopic properties of SNe Ia, providing a different perspective
on the properties of the unburned material; the radioactive and stable
nickel produced; progenitor magnetic fields; and searches for possible
signatures of companion stars. This paper includes data gathered
with the 6.5-m Magellan telescopes at Las Campanas Observatory, Chile.
Title: Reflection of Acoustic Modes on Sunspots
Authors: Waidele, Matthias; Glogowski, Kolja; Roth, Markus
Bibcode: 2018csc..confE.123W
Altcode:
Sunspots are known to strongly influence solar acoustic modes. There
is a variety of possible interactions of the magnetic field and the
waves, one of them being reflection. Assuming that part of a wave got
reflected at the subsurface magnetic fluxtube it should be detectable at
the surface again. In our studies we use the helioseismic Fourier-Hankel
analysis method to decompose sunspot data of 6 days recorded by SDO/HMI
into in and outgoing waves. The power spectrum of outgoing waves shows
a signal that could theoretically be contributed to wave reflection
at the sunspot.
Title: GONG p-Mode Parameters Through Two Solar Cycles
Authors: Kiefer, René; Komm, Rudi; Hill, Frank; Broomhall, Anne-Marie;
Roth, Markus
Bibcode: 2018SoPh..293..151K
Altcode: 2018arXiv181009324K
We investigate the parameters of global solar p-mode oscillations,
namely damping width Γ , amplitude A , mean squared velocity
«v2», energy E , and energy supply rate d E /d t , derived
from two solar cycles' worth (1996 - 2018) of Global Oscillation Network
Group (GONG) time series for harmonic degrees l =0 -150 . We correct for
the effect of fill factor, apparent solar radius, and spurious jumps in
the mode amplitudes. We find that the amplitude of the activity-related
changes of Γ and A depends on both frequency and harmonic degree of the
modes, with the largest variations of Γ for modes with 2400 μ Hz≤ν
≤3300 μ Hz and 31 ≤l ≤60 with a minimum-to-maximum variation of
26.6 ±0.3 % and of A for modes with 2400 μ Hz≤ν ≤3300 μ Hz and
61 ≤l ≤100 with a minimum-to-maximum variation of 27.4 ±0.4 % . The
level of correlation between the solar radio flux F10.7 and
mode parameters also depends on mode frequency and harmonic degree. As
a function of mode frequency, the mode amplitudes are found to follow
an asymmetric Voigt profile with νmax=3073.59 ±0.18 μ
Hz. From the mode parameters, we calculate physical mode quantities
and average them over specific mode frequency ranges. In this way, we
find that the mean squared velocities «v2» and energies
E of p modes are anticorrelated with the level of activity, varying by
14.7 ±0.3 % and 18.4 ±0.3 % , respectively, and that the mode energy
supply rates show no significant correlation with activity. With this
study we expand previously published results on the temporal variation
of solar p-mode parameters. Our results will be helpful to future
studies of the excitation and damping of p modes, i.e., the interplay
between convection, magnetic field, and resonant acoustic oscillations.
Title: Born Kernels for the Helioseismic Fourier-Legendre Analysis
Method
Authors: Hecht, Emanuel; Roth, Markus
Bibcode: 2018ApJ...862..145H
Altcode:
Measuring large-scale flows like the meridional flow with helioseismic
methods plays a crucial role for understanding solar dynamics. In this
work, we develop a detailed forward model for the Fourier-Legendre
analysis method. This method has initially been applied for measuring
the meridional flow by Braun & Fan, who observed frequency
shifts between poleward and equatorward traveling p-modes. However,
a detailed theoretical model based on a description of the solar
internal wavefield is lacking. We therefore describe the effect of
advection on the acoustic wavefronts in the first Born approximation
following the framework of Gizon & Birch. We derive 2D sensitivity
kernels for a suitable and unified definition of the frequency shift,
and validate them on the example of a meridional flow. Finally, an
inversion technique to estimate the meridional flow is developed on the
basis of synthetic data from a simulation of linear wave propagation.
Title: Design of a next generation synoptic solar observing network:
solar physics research integrated network group (SPRING)
Authors: Gosain, Sanjay; Roth, Markus; Hill, Frank; Pevtsov, Alexei;
Martinez Pillet, Valentin; Thompson, Michael J.
Bibcode: 2018SPIE10702E..4HG
Altcode:
Long-term synoptic observations of the Sun in different wavelength
regions are essential to understand its secular behavior. Such
observations have proven very important for discovery of 11 year
solar activity cycle, 22 year magnetic cycle, polar field reversals,
Hale's polarity law, Joy's law, that helped Babcock and Leighton
to propose famous solar dynamo model. In more recent decades, the
societal impact of the secular changes in Sun's output has been felt in
terms of solar inputs to terrestrial climate-change and space-weather
hazards. Further, it has been realized that to better understand the
activity phenomena such as flares and coronal mass ejections (CMEs)
one needs synoptic observations in multiple spectral lines to enable
tomographic inference of physical parameters. Currently, there are
both space and ground based synoptic observatories. However, given
the requirements for the long-term stability and reliability of such
synoptic datasets, ground-based facilities are more preferable. Also,
the ground based observatories are easy to maintain or upgrade while
detailed and frequent calibrations are easily possible. The only
ground-based facility that currently provides full-disk velocity and
magnetic field maps of the Sun around the clock and at good cadence,
is the Global Oscillations Network Group (GONG) network of National
Solar Observatory (NSO) which is operational since the mid 90s. Due
to its aging instrumentation, operating for nearly three decades, and
new requirements to obtain multiwavelength observations, a need is felt
in the solar community to build a next generation synoptic observatory
network. A group of international observatories have come together under
the auspices of SOLARNET program, funded by European Union (EU), to
carryout a preliminary design study of such a synoptic solar observing
facility called "SPRING", which stands for Solar Physics Research
Integrated Network Group. In this article we will present concept of
SPRING and the optical design concept of its major instruments.ts.
Title: The Effect of Toroidal Magnetic Fields on Solar Oscillation
Frequencies
Authors: Kiefer, René; Roth, Markus
Bibcode: 2018ApJ...854...74K
Altcode: 2018arXiv180107932K
Solar oscillation frequencies change with the level of magnetic
activity. Localizing subsurface magnetic field concentrations in
the Sun with helioseismology will help us to understand the solar
dynamo. Because the magnetic fields are not considered in standard
solar models, adding them to the basic equations of stellar structure
changes the eigenfunctions and eigenfrequencies. We use quasi-degenerate
perturbation theory to calculate the effect of toroidal magnetic
fields on solar oscillation mean multiplet frequencies for six field
configurations. In our calculations, we consider both the direct effect
of the magnetic field, which describes the coupling of modes, and the
indirect effect, which accounts for changes in stellar structure due
to the magnetic field. We limit our calculations to self-coupling of
modes. We find that the magnetic field affects the multiplet frequencies
in a way that depends on the location and the geometry of the field
inside the Sun. Comparing our theoretical results with observed
shifts, we find that strong tachocline fields cannot be responsible
for the observed frequency shifts of p modes over the solar cycle. We
also find that part of the surface effect in helioseismic oscillation
frequencies might be attributed to magnetic fields in the outer layers
of the Sun. The theory presented here is also applicable to models of
solar-like stars and their oscillation frequencies.
Title: Numerical Simulations of Kelvin-Helmholtz Instabilities in
a two-fluid regime
Authors: Piantschitsch, I.; Hanslmeier, A.; Roth, M.; Zaqarashvili,
T. V.
Bibcode: 2018CEAB...42...10P
Altcode:
The role of photospheric and chromospheric jets in heating the upper
solar atmosphere is not yet fully understood. Recent observational and
theoretical results have shown that Kelvin-Helmholtz Instabilities
(KHIs) occur in certain EUV jets with specific plasma density and
magnetic field parameters. KHIs have the potential to heat the
surrounding plasma and therefore may contribute to chromospheric
and coronal heating. Up to now, KHIs in the solar atmosphere have
been simulated mostly by using magnetohydrodynamic (MHD) models. We
show that simulations which are based on a two-fluid approach,
including collisional effects between neutral and ionized particles,
can lead to higher temperatures in the vortice-like structures along
the boundary layers of jets. Hence, the classical MHD approach may
have underestimated the role of KHIs in chromospheric and coronal
heating. Therefore, we suggest to include a two-fluid approach in
future simulations of KHIs in the upper layers of the solar atmosphere.
Title: Promoting access to and use of seismic data in a large
scientific community. SpaceInn data handling and archiving
Authors: Michel, Eric; Belkacem, Kevin; Samadi, Reza; Assis Peralta,
Raphael de; Renié, Christian; Abed, Mahfoudh; Lin, Guangyuan;
Christensen-Dalsgaard, Jørgen; Houdek, Günter; Handberg, Rasmus;
Gizon, Laurent; Burston, Raymond; Nagashima, Kaori; Pallé, Pere;
Poretti, Ennio; Rainer, Monica; Mistò, Angelo; Panzera, Maria Rosa;
Roth, Markus
Bibcode: 2017EPJWC.16001011M
Altcode:
The growing amount of seismic data available from space missions
(SOHO, CoRoT, Kepler, SDO,…) but also from ground-based facilities
(GONG, BiSON, ground-based large programmes…), stellar modelling
and numerical simulations, creates new scientific perspectives such as
characterizing stellar populations in our Galaxy or planetary systems
by providing model-independent global properties of stars such as mass,
radius, and surface gravity within several percent accuracy, as well as
constraints on the age. These applications address a broad scientific
community beyond the solar and stellar one and require combining
indices elaborated with data from different databases (e.g. seismic
archives and ground-based spectroscopic surveys). It is thus a basic
requirement to develop a simple and effcient access to these various
data resources and dedicated tools. In the framework of the European
project SpaceInn (FP7), several data sources have been developed or
upgraded. The Seismic Plus Portal has been developed, where synthetic
descriptions of the most relevant existing data sources can be found,
as well as tools allowing to localize existing data for given objects
or period and helping the data query. This project has been developed
within the Virtual Observatory (VO) framework. In this paper, we
give a review of the various facilities and tools developed within
this programme. The SpaceInn project (Exploitation of Space Data for
Innovative Helio- and Asteroseismology) has been initiated by the
European Helio- and Asteroseismology Network (HELAS).
Title: A new look at sunspot formation using theory and observations
Authors: Losada, I. R.; Warnecke, J.; Glogowski, K.; Roth, M.;
Brandenburg, A.; Kleeorin, N.; Rogachevskii, I.
Bibcode: 2017IAUS..327...46L
Altcode: 2017arXiv170404062L
Sunspots are of basic interest in the study of the Sun. Their
relevance ranges from them being an activity indicator of magnetic
fields to being the place where coronal mass ejections and flares
erupt. They are therefore also an important ingredient of space
weather. Their formation, however, is still an unresolved problem in
solar physics. Observations utilize just 2D surface information near the
spot, but it is debatable how to infer deep structures and properties
from local helioseismology. For a long time, it was believed that flux
tubes rising from the bottom of the convection zone are the origin of
the bipolar sunspot structure seen on the solar surface. However,
this theory has been challenged, in particular recently by new
surface observation, helioseismic inversions, and numerical models
of convective dynamos. In this article we discuss another theoretical
approach to the formation of sunspots: the negative effective magnetic
pressure instability. This is a large-scale instability, in which the
total (kinetic plus magnetic) turbulent pressure can be suppressed
in the presence of a weak large-scale magnetic field, leading to a
converging downflow, which eventually concentrates the magnetic field
within it. Numerical simulations of forced stratified turbulence have
been able to produce strong super-equipartition flux concentrations,
similar to sunspots at the solar surface. In this framework, sunspots
would only form close to the surface due to the instability constraints
on stratification and rotation. Additionally, we present some ideas
from local helioseismology, where we plan to use the Hankel analysis
to study the pre-emergence phase of a sunspot and to constrain its
deep structure and formation mechanism.
Title: The Direct Effect of Toroidal Magnetic Fields on Stellar
Oscillations: An Analytical Expression for the General Matrix Element
Authors: Kiefer, René; Schad, Ariane; Roth, Markus
Bibcode: 2017ApJ...846..162K
Altcode: 2017arXiv170902454K
Where is the solar dynamo located and what is its modus operandi? These
are still open questions in solar physics. Helio- and asteroseismology
can help answer them by enabling us to study solar and stellar
internal structures through global oscillations. The properties
of solar and stellar acoustic modes are changing with the level of
magnetic activity. However, until now, the inference on subsurface
magnetic fields with seismic measures has been very limited. The
aim of this paper is to develop a formalism to calculate the effect
of large-scale toroidal magnetic fields on solar and stellar global
oscillation eigenfunctions and eigenfrequencies. If the Lorentz force
is added to the equilibrium equation of motion, stellar eigenmodes
can couple. In quasi-degenerate perturbation theory, this coupling,
also known as the direct effect, can be quantified by the general
matrix element. We present the analytical expression of the matrix
element for a superposition of subsurface zonal toroidal magnetic
field configurations. The matrix element is important for forward
calculations of perturbed solar and stellar eigenfunctions and frequency
perturbations. The results presented here will help to ascertain solar
and stellar large-scale subsurface magnetic fields, and their geometric
configuration, strength, and change over the course of activity cycles.
Title: Comparison of Gaia and asteroseismic distances
Authors: Yıldız, M.; Ćelik Orhan, Z.; Örtel, S.; Roth, M.
Bibcode: 2017MNRAS.470L..25Y
Altcode: 2017arXiv170508313Y
Asteroseismology provides fundamental properties (mass, radius
and effective temperature) of solar-like oscillating stars using
so-called scaling relations. These properties allow the computation
of the asteroseismic distance of stars. We compare the asteroseismic
distances with the recently released Gaia distances for 74 stars
studied in Yıldız et al. There is a very good agreement between
these two distances; for 64 of these stars, the difference is less
than 10 per cent. However, a systematic difference is seen if we use
the effective temperature obtained by spectroscopic methods; the Gaia
distances are about 5 per cent greater than the asteroseismic distances.
Title: Inversions for Deep Solar Meridional Flow Using Spherical
Born Kernels
Authors: Böning, Vincent G. A.; Roth, Markus; Jackiewicz, Jason;
Kholikov, Shukur
Bibcode: 2017ApJ...845....2B
Altcode: 2017arXiv170708803B
The solar meridional flow is a crucial ingredient in modern
dynamo theory. Seismic estimates of this flow have, however,
been contradictory in deeper layers below about 0.9 {R}⊙
. Results from time-distance helioseismology have so far been
obtained using the ray approximation. Here, we perform inversions using
the Born approximation. The initial result is similar to the result
previously obtained by Jackiewicz et al. using ray kernels while using
the same set of GONG data and the SOLA inversion technique. However,
we show that the assumption of uncorrelated measurements used in
earlier studies may lead to inversion errors being underestimated
by a factor of about 2-4. In a second step, refined inversions are
performed using the full covariance matrix and a regularization for
cross-talk. As the results are found to depend on the threshold used
in the singular value decomposition, they were obtained for a medium
threshold ({10}-7{--}{10}-5, about 50% of the
values used) and a threshold lower by a factor of 10 (about 70% of the
values used). The result obtained with the medium threshold is again
similar to the original, with less latitudinal variation. However,
using the lower threshold, the inverted flow in the southern hemisphere
shows two or three cells stacked radially depending on the associated
radial flows. Both the single-cell and the multi-cell profiles are
consistent with the measured travel times. All our results confirm a
shallow return flow at about 0.9 {R}⊙ .
Title: Formation of diamonds in laser-compressed hydrocarbons at
planetary interior conditions
Authors: Kraus, D.; Vorberger, J.; Pak, A.; Hartley, N. J.; Fletcher,
L. B.; Frydrych, S.; Galtier, E.; Gamboa, E. J.; Gericke, D. O.;
Glenzer, S. H.; Granados, E.; MacDonald, M. J.; MacKinnon, A. J.;
McBride, E. E.; Nam, I.; Neumayer, P.; Roth, M.; Saunders, A. M.;
Schuster, A. K.; Sun, P.; van Driel, T.; Döppner, T.; Falcone, R. W.
Bibcode: 2017NatAs...1..606K
Altcode:
The effects of hydrocarbon reactions and diamond precipitation on
the internal structure and evolution of icy giant planets such
as Neptune and Uranus have been discussed for more than three
decades1. Inside these celestial bodies, simple
hydrocarbons such as methane, which are highly abundant in
the atmospheres2, are believed to undergo structural
transitions3,4 that release hydrogen from deeper layers
and may lead to compact stratified cores5-7. Indeed,
from the surface towards the core, the isentropes of Uranus and
Neptune intersect a temperature-pressure regime in which methane
first transforms into a mixture of hydrocarbon polymers8,
whereas, in deeper layers, a phase separation into diamond and
hydrogen may be possible. Here we show experimental evidence for
this phase separation process obtained by in situ X-ray diffraction
from polystyrene (C8H8)n samples
dynamically compressed to conditions around 150 GPa and 5,000 K;
these conditions resemble the environment around 10,000 km below the
surfaces of Neptune and Uranus9. Our findings demonstrate
the necessity of high pressures for initiating carbon-hydrogen
separation3 and imply that diamond precipitation may require
pressures about ten times as high as previously indicated by static
compression experiments4,8,10. Our results will inform
mass-radius relationships of carbon-bearing exoplanets11,
provide constraints for their internal layer structure and improve
evolutionary models of Uranus and Neptune, in which carbon-hydrogen
separation could influence the convective heat transport7.
Title: NGC 6334 V revisited: The complex nature of the infrared nebula
Authors: Tapia, M.; Persi, P.; Roth, M.
Bibcode: 2017RMxAC..49..111T
Altcode:
A comprehensive analysis is presented of the most recent infrared
observations of the small, very young and enigmatic infrared
nebula associated with NGC 6334-V. We re-analized images from the
Spitzer/IRAC (3.6 a 8 μm), Herschel/SPIRE/PACS (70 a 500 μm), VISTA
(1.2 a 2.2 μm), VLT/VISIR (11.3 a 18.7 μm) and HST/NICMOS (2.0 μm)
archives. The very high spatial resolution from the latter two sets,
combined with very recent sub-millimetre maps, allow us to suggest
several possible star-formation scenarios that explain the observed
infrared and radio properties of the region. Evidence is provided of
the presence of a small population of low and medium-mass young stars
embedded in the infrared reflection nebulosity NGC 6334 V that coexist
with the nearby much younger Class 0 protostars.
Title: On the effect of vorticity on the propagation of internal
gravity waves.
Authors: Vigeesh, G.; Steiner, O.; Calvo, F.; Roth, M.
Bibcode: 2017MmSAI..88...54V
Altcode:
We compare different models of solar surface convection to study
vorticity and how it can influence the propagation of internal
gravity waves. We conclude that simulations performed with higher grid
resolution may have a reduced gravity wave flux in the lower part of
the atmosphere due to strong vorticity. We also show that the vertical
extent of the allowed region of propagation depends on the magnetic
field inclination.
Title: Validation of Spherical Born Approximation Sensitivity
Functions for Measuring Deep Solar Meridional Flow
Authors: Böning, Vincent G. A.; Roth, Markus; Jackiewicz, Jason;
Kholikov, Shukur
Bibcode: 2017ApJ...838...53B
Altcode: 2017arXiv170303700B
Accurate measurements of deep solar meridional flow are of vital
interest for understanding the solar dynamo. In this paper, we validate
a recently developed method for obtaining sensitivity functions
(kernels) for travel-time measurements to solar interior flows using
the Born approximation in spherical geometry, which is expected to
be more accurate than the classical ray approximation. Furthermore,
we develop a numerical approach to efficiently compute a large number
of kernels based on the separability of the eigenfunctions into
their horizontal and radial dependence. The validation is performed
using a hydrodynamic simulation of linear wave propagation in the Sun,
which includes a standard single-cell meridional flow profile. We show
that, using the Born approximation, it is possible to accurately model
observational quantities relevant for time-distance helioseismology such
as the mean power spectrum, disk-averaged cross-covariance functions,
and travel times in the presence of a flow field. In order to closely
match the model to observations, we show that it is beneficial to use
mode frequencies and damping rates that were extracted from the measured
power spectrum. Furthermore, the contribution of the radial flow to
the total travel time is found to reach 20% of the contribution of the
horizontal flow at travel distances over 40°. Using the Born kernels
and a 2D SOLA inversion of travel times, we can recover most features
of the input meridional flow profile. The Born approximation is thus
a promising method for inferring large-scale solar interior flows.
Title: Stellar magnetic activity and variability of oscillation
parameters: An investigation of 24 solar-like stars observed by Kepler
Authors: Kiefer, René; Schad, Ariane; Davies, Guy; Roth, Markus
Bibcode: 2017A&A...598A..77K
Altcode: 2016arXiv161102029K
Context. The Sun and solar-like stars undergo activity cycles for which
the underlying mechanisms are not well understood. The oscillations
of the Sun are known to vary with its activity cycle and these changes
provide diagnostics on the conditions below the photosphere. Kepler has
detected solar-like oscillations in hundreds of stars but as of yet,
no widespread detection of signatures of magnetic activity cycles in
the oscillation parameters of these stars have been reported.
Aims: We analysed the photometric short cadence Kepler time series
of a set of 24 solar-like stars, which were observed for at least
960 d each, with the aim to find signatures of stellar magnetic
activity in the oscillation parameters.
Methods: We analyse
the temporal evolution of oscillation parameters by measuring mode
frequency shifts, changes in the height of the p-mode envelope,
as well as granulation timescales.
Results: For 23 of the 24
investigated stars, we find significant frequency shifts in time. We
present evidence for magnetic activity in six of these stars. We find
that the amplitude of the frequency shifts decreases with stellar age
and rotation period. For KIC 8006161 (the most prominent example),
we find that frequency shifts are smallest for the lowest and largest
for the highest p-mode frequencies, as they are for the Sun.
Conclusions: These findings show that magnetic activity can be
routinely observed in the oscillation parameters for solar-like stars,
which opens up the possibility of placing the solar activity cycle in
the context of other stars by asteroseismology.
Title: Recent Developments in Helioseismic Analysis Methods and
Solar Data Assimilation
Authors: Schad, A.; Jouve, L.; Duvall, T. L., Jr.; Roth, M.;
Vorontsov, S.
Bibcode: 2017hdsi.book..227S
Altcode:
No abstract at ADS
Title: The Importance of Long-Term Synoptic Observations and Data
Sets for Solar Physics and Helioseismology
Authors: Elsworth, Yvonne; Broomhall, Anne-Marie; Gosain, Sanjay;
Roth, Markus; Jefferies, Stuart M.; Hill, Frank
Bibcode: 2017hdsi.book..143E
Altcode:
No abstract at ADS
Title: Helioseismology and Dynamics of the Solar Interior
Authors: Thompson, M. J.; Brun, A. S.; Culhane, J. L.; Gizon, L.;
Roth, M.; Sekii, T.
Bibcode: 2017hdsi.book.....T
Altcode:
No abstract at ADS
Title: The Solar Physics Research Integrated Network Group - SPRING
Authors: Roth, Markus
Bibcode: 2017psio.confE..88R
Altcode:
No abstract at ADS
Title: Preface: Helioseismology and Dynamics of the Solar Interior
Authors: Gizon, Laurent; Thompson, Michael J.; Brun, A. Sacha; Culhane,
J. Len; Roth, Markus; Sekii, Takashi
Bibcode: 2017hdsi.book....1G
Altcode:
No abstract at ADS
Title: Solar Dynamics, Rotation, Convection and Overshoot
Authors: Hanasoge, S.; Miesch, M. S.; Roth, M.; Schou, J.; Schüssler,
M.; Thompson, M. J.
Bibcode: 2017hdsi.book...85H
Altcode:
No abstract at ADS
Title: Search for hidden-photon Dark Matter with the FUNK experiment
Authors: Veberic, D.; Andrianavalomahefa, A.; Daumiller, K.; Döbrich,
B.; Engel, R.; Jaeckel, J.; Kowalski, M.; Lindner, A.; Mathes, H. J.;
Redondo, J.; Roth, M.; Schwetz-Mangold, T.; Schäfer, C. M.; Ulrich, R.
Bibcode: 2017ICRC...35..880V
Altcode: 2017PoS...301..880V
No abstract at ADS
Title: Impact of muon detection thresholds on the separability of
primary cosmic rays
Authors: Müller, S.; Engel, R.; Pierog, T.; Roth, M.
Bibcode: 2017ICRC...35..311M
Altcode: 2017PoS...301..311M
No abstract at ADS
Title: The SpaceInn-SISMA Database: Characterization of a Large
Sample of Variable and Active Stars by Means of Harps Spectra
Authors: Rainer, M.; Poretti, E.; Mistò, A.; Panzera, M. R.; Molinaro,
M.; Cepparo, F.; Roth, M.; Michel, E.; Monteiro, M. J. P. F. G.
Bibcode: 2016AJ....152..207R
Altcode: 2016arXiv161102715R
We created a large database of physical parameters and variability
indicators by fully reducing and analyzing the large number of spectra
taken to complement the asteroseismic observations of the COnvection,
ROtation and planetary Transits (CoRoT) satellite. 7103 spectra of 261
stars obtained with the ESO echelle spectrograph HARPS have been stored
in the VO-compliant database Spectroscopic Indicators in a SeisMic
Archive (SISMA), along with the CoRoT photometric data of the 72 CoRoT
asteroseismic targets. The remaining stars belong to the same variable
classes of the CoRoT targets and were observed to better characterize
the properties of such classes. Several useful variability indicators
(mean line profiles, indices of differential rotation, activity and
emission lines) together with v\sin I and radial-velocity measurements
have been extracted from the spectra. The atmospheric parameters
{T}{eff},{log}g, and [Fe/H] have been computed following
a homogeneous procedure. As a result, we fully characterize a sample
of new and known variable stars by computing several spectroscopic
indicators, also providing some cases of simultaneous photometry and
spectroscopy.
Title: The E-ELT multi-object spectrograph: latest news from MOSAIC
Authors: Hammer, F.; Morris, S.; Kaper, L.; Barbuy, B.; Cuby, J. G.;
Roth, M.; Jagourel, P.; Evans, C. J.; Puech, M.; Fitzsimons, E.;
Dalton, G.; Rodrigues, M.
Bibcode: 2016SPIE.9908E..24H
Altcode: 2016arXiv160901305H
There are 8000 galaxies, including 1600 at z >= 1.6, which
could be simultaneously observed in an E-ELT field of view of 40
arcmin2. A considerable fraction of astrophysical discoveries
require large statistical samples, which can only be obtained with
multi-object spectrographs (MOS). MOSAIC will provide a vast discovery
space, enabled by a multiplex of 200 and spectral resolving powers
of R=5000 and 20000. MOSAIC will also offer the unique capability of
more than 10 `high-definition' (multi-object adaptive optics, MOAO)
integral-field units, optimised to investigate the physics of the
sources of reionization. The combination of these modes will make
MOSAIC the world-leading MOS facility, contributing to all fields of
contemporary astronomy, from extra-solar planets, to the study of the
halo of the Milky Way and its satellites, and from resolved stellar
populations in nearby galaxies out to observations of the earliest
`first-light' structures in the Universe. It will also study the
distribution of the dark and ordinary matter at all scales and epochs
of the Universe. Recent studies of critical technical issues such as
sky-background subtraction and MOAO have demonstrated that such a MOS
is feasible with state-of-the-art technology and techniques. Current
studies of the MOSAIC team include further trade-offs on the wavelength
coverage, a solution for compensating for the non-telecentric new
design of the telescope, and tests of the saturation of skylines
especially in the near-IR bands. In the 2020s the E-ELT will become the
world's largest optical/IR telescope, and we argue that it has to be
equipped as soon as possible with a MOS to provide the most efficient,
and likely the best way to follow-up on James Webb Space Telescope
(JWST) observations.
Title: Verification of the helioseismic Fourier-Legendre analysis
for meridional flow measurements
Authors: Roth, M.; Doerr, H. -P.; Hartlep, T.
Bibcode: 2016A&A...592A.106R
Altcode: 2016arXiv160605202R
Context. Measuring the Sun's internal meridional flow is one of the
key issues of helioseismology. Using the Fourier-Legendre analysis is
a technique for addressing this problem.
Aims: We validate this
technique with the help of artificial helioseismic data.
Methods:
The analysed data set was obtained by numerically simulating the effect
of the meridional flow on the seismic wave field in the full volume
of the Sun. In this way, a 51.2-h long time series was generated. The
resulting surface velocity field is then analyzed in various settings:
Two 360° × 90° halfspheres, two 120° × 60° patches on the front
and farside of the Sun (North and South, respectively) and two 120° ×
60° patches on the northern and southern frontside only. We compare
two possible measurement setups: observations from Earth and from an
additional spacecraft on the solar farside, and observations from
Earth only, in which case the full information of the global solar
oscillation wave field was available.
Results: We find that,
with decreasing observing area, the accessible depth range decreases:
the 360° × 90° view allows us to probe the meridional flow almost to
the bottom of the convection zone, while the 120° × 60° view means
only the outer layers can be probed.
Conclusions: These results
confirm the validity of the Fourier-Legendre analysis technique for
helioseismology of the meridional flow. Furthermore these flows are
of special interest for missions like Solar Orbiter that promises to
complement standard helioseismic measurements from the solar nearside
with farside observations.
Title: Sensitivity Kernels for Flows in Time-Distance Helioseismology:
Extension to Spherical Geometry
Authors: Böning, Vincent G. A.; Roth, Markus; Zima, Wolfgang; Birch,
Aaron C.; Gizon, Laurent
Bibcode: 2016ApJ...824...49B
Altcode: 2016arXiv160403803B
We extend an existing Born approximation method for calculating the
linear sensitivity of helioseismic travel times to flows from Cartesian
to spherical geometry. This development is necessary for using the
Born approximation for inferring large-scale flows in the deep solar
interior. As first sanity check, we compare two f-mode kernels from our
spherical method and from an existing Cartesian method. The horizontal
and total integrals agree to within 0.3%. As a second consistency test,
we consider a uniformly rotating Sun and a travel distance of 42°. The
analytical travel-time difference agrees with the forward-modeled
travel-time difference to within 2%. In addition, we evaluate the impact
of different choices of filter functions on the kernels for a meridional
travel distance of 42°. For all filters, the sensitivity is found to
be distributed over a large fraction of the convection zone. We show
that the kernels depend on the filter function employed in the data
analysis process. If modes of higher harmonic degree (90 ≲ l ≲ 170)
are permitted, a noisy pattern of a spatial scale corresponding to l
≈ 260 appears near the surface. When mainly low-degree modes are used
(l ≲ 70), the sensitivity is concentrated in the deepest regions and
it visually resembles a ray-path-like structure. Among the different
low-degree filters used, we find the kernel for phase-speed-filtered
measurements to be best localized in depth.
Title: Born Sensitivity Kernels in Spherical Geometry for Meridional
Flows
Authors: Jackiewicz, Jason; Boening, Vincent; Roth, Markus; Kholikov,
Shukur
Bibcode: 2016SPD....47.0707J
Altcode:
Measuring meridional flows deep in the solar convection zone is
challenging because of their small amplitudes compared to other
background signals. Typically such inferences are made using a ray
theory that is best suited for slowly-varying flows. The implementation
of finite-frequency Born theory has been shown to be more accurate
for modeling flows of complex spatial structure in the near-surface
region. Only until recently were such functions available in spherical
geometry, which is necessary for applications to meridional flows. Here
we compare these sensitivity kernels with corresponding ray kernels
in a forward and inverse problem using numerical simulations. We show
that they are suitable for inverting travel-time measurements and are
more sensitive to small-scale variations of deep circulations.
Title: Observational Evidence for Variations of the Acoustic Cutoff
Frequency with Height in the Solar Atmosphere
Authors: Wiśniewska, A.; Musielak, Z. E.; Staiger, J.; Roth, M.
Bibcode: 2016ApJ...819L..23W
Altcode:
Direct evidence for the existence of an acoustic cutoff frequency in
the solar atmosphere is given by observations performed by using the
HELioseismological Large Regions Interferometric DEvice operating on the
Vacuum Tower Telescope located on Tenerife. The observational results
demonstrate variations of the cutoff with atmospheric heights. The
observed variations of the cutoff are compared to theoretical
predictions made by using five acoustic cutoff frequencies that
have been commonly used in helioseismology and asteroseismology. The
comparison shows that none of the theoretical predictions is fully
consistent with the observational data. The implication of this finding
is far reaching as it urgently requires either major revisions of the
existing methods of finding acoustic cutoff frequencies or developing
new methods that would much better account for the physical picture
underlying the concept of cutoff frequencies in inhomogeneous media.
Title: The Importance of Long-Term Synoptic Observations and Data
Sets for Solar Physics and Helioseismology
Authors: Elsworth, Yvonne; Broomhall, Anne-Marie; Gosain, Sanjay;
Roth, Markus; Jefferies, Stuart M.; Hill, Frank
Bibcode: 2015SSRv..196..137E
Altcode: 2015SSRv..tmp..106E
A casual single glance at the Sun would not lead an observer to conclude
that it varies. The discovery of the 11-year sunspot cycle was only
made possible through systematic daily observations of the Sun over
150 years and even today historic sunspot drawings are used to study
the behavior of past solar cycles. The origin of solar activity is
still poorly understood as shown by the number of different models
that give widely different predictions for the strength and timing
of future cycles. Our understanding of the rapid transient phenomena
related to solar activity, such as flares and coronal mass ejections
(CMEs) is also insufficient and making reliable predictions of these
events, which can adversely impact technology, remains elusive. There
is thus still much to learn about the Sun and its activity that requires
observations over many solar cycles. In particular, modern helioseismic
observations of the solar interior currently span only 1.5 cycles,
which is far too short to adequately sample the characteristics of
the plasma flows that govern the dynamo mechanism underlying solar
activity. In this paper, we review some of the long-term solar and
helioseismic observations and outline some future directions.
Title: Solar Dynamics, Rotation, Convection and Overshoot
Authors: Hanasoge, S.; Miesch, M. S.; Roth, M.; Schou, J.; Schüssler,
M.; Thompson, M. J.
Bibcode: 2015SSRv..196...79H
Altcode: 2015SSRv..tmp...24H; 2015arXiv150308539H
We discuss recent observational, theoretical and modeling progress
made in understanding the Sun's internal dynamics, including its
rotation, meridional flow, convection and overshoot. Over the past
few decades, substantial theoretical and observational effort has
gone into appreciating these aspects of solar dynamics. A review of
these observations, related helioseismic methodology and inference and
computational results in relation to these problems is undertaken here.
Title: Recent Developments in Helioseismic Analysis Methods and
Solar Data Assimilation
Authors: Schad, A.; Jouve, L.; Duvall, T. L.; Roth, M.; Vorontsov, S.
Bibcode: 2015SSRv..196..221S
Altcode: 2015SSRv..tmp...84S; 2016arXiv160304742S
We review recent advances and results in enhancing and developing
helioseismic analysis methods and in solar data assimilation. In the
first part of this paper we will focus on selected developments in
time-distance and global helioseismology. In the second part, we review
the application of data assimilation methods on solar data. Relating
solar surface observations as well as helioseismic proxies with solar
dynamo models by means of the techniques from data assimilation is a
promising new approach to explore and to predict the magnetic activity
cycle of the Sun.
Title: Search for dark matter in the hidden-photon sector with a
large spherical mirror
Authors: FUNK Experiment, The; :; Veberič, Darko; Daumiller, Kai;
Döbrich, Babette; Engel, Ralph; Jaeckel, Joerg; Kowalski, Marek;
Lindner, Axel; Mathes, Hermann-Josef; Redondo, Javier; Roth, Markus;
Schäfer, Christoph M.; Ulrich, Ralf
Bibcode: 2015arXiv150902386F
Altcode: 2015arXiv150902386V
If dark matter consists of hidden-sector photons which kinetically
mix with regular photons, a tiny oscillating electric-field component
is present wherever we have dark matter. In the surface of conducting
materials this induces a small probability to emit single photons almost
perpendicular to the surface, with the corresponding photon frequency
matching the mass of the hidden photons. We report on a construction
of an experimental setup with a large ~14 m2 spherical metallic mirror
that will allow for searches of hidden-photon dark matter in the eV
and sub-eV range by application of different electromagnetic radiation
detectors. We discuss sensitivity and accessible regions in the dark
matter parameter space.
Title: Erratum: An Upper Bound from Helioseismology
on the Stochastic Background of Gravitational Waves (2014, ApJ, 784, 88)
Authors: Siegel, Daniel M.; Roth, Markus
Bibcode: 2015ApJ...810...84S
Altcode:
No abstract at ADS
Title: The energy spectrum of cosmic rays in the range from 10^{14}
to 10^{18}eV
Authors: Schoo, S.; Apel, W. D.; Arteaga-Velázquez, J. C.; Bekk,
K.; Bertaina, M.; Blümer, J.; Bozdog, H.; Brancus, I. M.; Cantoni,
E.; Chiavassa, A.; Cossavella, F.; Daumiller, K.; de Souza, V.;
di Pierro, F.; Doll, P.; Engel, R.; Fuhrmann, D.; Gherghel-Lascu,
A.; Gils, H. J.; Glasstetter, R.; Grupen, C.; Haungs, A.; Heck, D.;
Hörandel, J. R.; Huber, D.; Huege, T.; Kampert, K. -H.; Kang, D.;
Klages, H. O.; Link, K.; Łczak, P.; Mathes, H. J.; Mayer, H. J.;
Milke, J.; Mitrica, B.; Morello, C.; Oehlschläger, J.; Ostapchenko,
S.; Palmieri, N.; Pierog, T.; Rebel, H.; Roth, M.; Schieler, H.;
Schröder, F. G.; Sima, O.; Toma, G.; Trinchero, G. C.; Ulrich, H.;
Weindl, A.; Wochele, J.; Zabierowski, J.; KASCADE-Grande Collaboration
Bibcode: 2015ICRC...34..263S
Altcode: 2015PoS...236..263S
No abstract at ADS
Title: Search for dark matter in the hidden-photon sector with a
large spherical mirror
Authors: Veberic, Darko; Daumiller, Kai; Döbrich, Babette; Engel,
Ralph; Jaeckel, Joerg; Kowalski, Marek; Lindner, Axel; Mathes,
Hermann-Josef; Redondo, Javier; Roth, Markus; Schäfer, Christoph;
Ulrich, Ralf; Experiment, FUNK
Bibcode: 2015ICRC...34.1191V
Altcode: 2015PoS...236.1191V
No abstract at ADS
Title: Improving the universality reconstruction using independent
measurements of water-Cherenkov detectors and additional muon counters
Authors: Josebachuili, M.; Ave, M.; Roth, M.; Melo, D.; Sánchez,
F.; Etchegoyen, A.
Bibcode: 2015ICRC...34..409J
Altcode: 2015PoS...236..409J
No abstract at ADS
Title: A CORSIKA study on the influence of muon detector thresholds
on the separability of primary cosmic rays at highest energies
Authors: Mueller, S.; Roth, M.
Bibcode: 2015ICRC...34..419M
Altcode: 2015PoS...236..419M
No abstract at ADS
Title: A universal description of temporal and lateral distributions
of ground particles in extensive air showers
Authors: Ave, Maximo; Roth, Markus; Schulz, Alexander
Bibcode: 2015ICRC...34..378A
Altcode: 2015PoS...236..378A
No abstract at ADS
Title: Strong near-infrared carbon in the Type Ia supernova iPTF13ebh
Authors: Hsiao, E. Y.; Burns, C. R.; Contreras, C.; Höflich, P.; Sand,
D.; Marion, G. H.; Phillips, M. M.; Stritzinger, M.; González-Gaitán,
S.; Mason, R. E.; Folatelli, G.; Parent, E.; Gall, C.; Amanullah, R.;
Anupama, G. C.; Arcavi, I.; Banerjee, D. P. K.; Beletsky, Y.; Blanc,
G. A.; Bloom, J. S.; Brown, P. J.; Campillay, A.; Cao, Y.; De Cia,
A.; Diamond, T.; Freedman, W. L.; Gonzalez, C.; Goobar, A.; Holmbo,
S.; Howell, D. A.; Johansson, J.; Kasliwal, M. M.; Kirshner, R. P.;
Krisciunas, K.; Kulkarni, S. R.; Maguire, K.; Milne, P. A.; Morrell,
N.; Nugent, P. E.; Ofek, E. O.; Osip, D.; Palunas, P.; Perley, D. A.;
Persson, S. E.; Piro, A. L.; Rabus, M.; Roth, M.; Schiefelbein, J. M.;
Srivastav, S.; Sullivan, M.; Suntzeff, N. B.; Surace, J.; Woźniak,
P. R.; Yaron, O.
Bibcode: 2015A&A...578A...9H
Altcode: 2015arXiv150302293H
We present near-infrared (NIR) time-series spectroscopy, as well as
complementary ultraviolet (UV), optical, and NIR data, of the Type
Ia supernova (SN Ia) iPTF13ebh, which was discovered within two
days from the estimated time of explosion. The first NIR spectrum
was taken merely 2.3 days after explosion and may be the earliest
NIR spectrum yet obtained of a SN Ia. The most striking features
in the spectrum are several NIR C i lines, and the C iλ1.0693 μm
line is the strongest ever observed in a SN Ia. Interestingly, no
strong optical C ii counterparts were found, even though the optical
spectroscopic time series began early and is densely cadenced. Except
at the very early epochs, within a few days from the time of explosion,
we show that the strong NIR C i compared to the weaker optical C ii
appears to be general in SNe Ia. iPTF13ebh is a fast decliner with
Δm15(B) = 1.79 ± 0.01, and its absolute magnitude obeys
the linear part of the width-luminosity relation. It is therefore
categorized as a "transitional" event, on the fast-declining end of
normal SNe Ia as opposed to subluminous/91bg-like objects. iPTF13ebh
shows NIR spectroscopic properties that are distinct from both the
normal and subluminous/91bg-like classes, bridging the observed
characteristics of the two classes. These NIR observations suggest
that composition and density of the inner core are similar to that
of 91bg-like events, and that it has a deep-reaching carbon burning
layer that is not observed in more slowly declining SNe Ia. There is
also a substantial difference between the explosion times inferred
from the early-time light curve and the velocity evolution of the
Si iiλ0.6355 μm line, implying a long dark phase of ~4 days. This paper includes data gathered with the 6.5-m Magellan
Telescopes located at Las Campanas Observatory, Chile.Optical and
NIR spectra are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr
(ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/578/A9
Title: Determination of fundamental asteroseismic parameters using
the Hilbert transform
Authors: Kiefer, René; Schad, Ariane; Herzberg, Wiebke; Roth, Markus
Bibcode: 2015A&A...578A..56K
Altcode: 2015arXiv150408066K
Context. Solar-like oscillations exhibit a regular pattern
of frequencies. This pattern is dominated by the small and large
frequency separations between modes. The accurate determination of these
parameters is of great interest, because they give information about
e.g. the evolutionary state and the mass of a star.
Aims: We want
to develop a robust method to determine the large and small frequency
separations for time series with low signal-to-noise ratio. For this
purpose, we analyse a time series of the Sun from the GOLF instrument
aboard SOHO and a time series of the star KIC 5184732 from the NASA
Kepler satellite by employing a combination of Fourier and Hilbert
transform.
Methods: We use the analytic signal of filtered
stellar oscillation time series to compute the signal envelope. Spectral
analysis of the signal envelope then reveals frequency differences of
dominant modes in the periodogram of the stellar time series.
Results: With the described method the large frequency separation
Δν can be extracted from the envelope spectrum even for data of
poor signal-to-noise ratio. A modification of the method allows for
an overview of the regularities in the periodogram of the time series.
Title: Multi-height spectroscopy for probing the solar atmosphere
Authors: Wiśniewska, A.; Roth, M.; Staiger, J.
Bibcode: 2015CEAB...39..101W
Altcode:
We present preliminary results from multi-height observations,
taken with the HELLRIDE (HELioseismic Large Region Interferometric
DEvice) instrument at the VTT (Vacuum Tower Telescope) in Izaña,
Tenerife. The goal of this work is to study solar oscillations at
different atmospheric heights. The data was obtained in May 2014 for
10 different wavelengths with high spatial, spectral and temporal
resolution. In this paper we discuss the results from quiet sun
measurements. The region was selected in such a way to be near to the
disk center. Using spectral and cross-spectral analysis methods we
derive phase differences of waves propagating between the atmospheric
layers. The formation heights of the photospheric spectral lines were
calculated by τ^c_{5000} = 1 in agreement with an LTE approximation
and chromospheric lines with an NLTE method, respectively. We find
that the acoustic cut-off frequency is a function of height in the
solar atmosphere.
Title: A comparison between the observed and predicted amplitude of
the 24th solar cycle
Authors: Brajša, R.; Verbanac, G.; Sudar, D.; Skokić, I.; Žic,
T.; Hanslmeier, A.; Wöhl, H.; Roth, M.; Mursula, K.; Zhang, L.
Bibcode: 2015CEAB...39..135B
Altcode:
In present work we compared the measured and predicted amplitudes of
the 24th solar cycle. The modified minimum--maximum method,
belonging to the precursor class of methods, was applied to the smoothed
monthly sunspot number values (the ``old'' data set, used before the
change introduced on July 1st, 2015). The maximum of the
24th solar cycle occurred in April 2014 with an amplitude of
R=82 and this observed value is very close to our mean predicted value
R=83. The maximum was significantly weaker than in several previous
cycles. Additionally, a curious solar activity minimum of 2008,
between the solar cycles no.~23 and no.~24 was analysed, as well as
the shape of the maximum profile. The maximum of the 24th
solar cycle had a double-peak, the second one being higher than the
first one. The obtained results represent a strong indication that
the minimum--maximum method is a reliable tool for the solar cycle
prediction, using data available already 3 years before the preceding
minimum of solar activity.
Title: Science case and requirements for the MOSAIC concept for a
multi-object spectrograph for the European Extremely Large Telescope
Authors: Evans, C. J.; Puech, M.; Barbuy, B.; Bonifacio, P.; Cuby,
J. -G.; Guenther, E.; Hammer, F.; Jagourel, P.; Kaper, L.; Morris,
S. L.; Afonso, J.; Amram, P.; Aussel, H.; Basden, A.; Bastian,
N.; Battaglia, G.; Biller, B.; Bouché, N.; Caffau, E.; Charlot,
S.; Clénet, Y.; Combes, F.; Conselice, C.; Contini, T.; Dalton,
G.; Davies, B.; Disseau, K.; Dunlop, J.; Fiore, F.; Flores, H.;
Fusco, T.; Gadotti, D.; Gallazzi, A.; Giallongo, E.; Gonçalves,
T.; Gratadour, D.; Hill, V.; Huertas-Company, M.; Ibata, R.; Larsen,
S.; Le Fèvre, O.; Lemasle, B.; Maraston, C.; Mei, S.; Mellier, Y.;
Östlin, G.; Paumard, T.; Pello, R.; Pentericci, L.; Petitjean, P.;
Roth, M.; Rouan, D.; Schaerer, D.; Telles, E.; Trager, S.; Welikala,
N.; Zibetti, S.; Ziegler, B.
Bibcode: 2014SPIE.9147E..96E
Altcode: 2014arXiv1406.6369E
Over the past 18 months we have revisited the science requirements
for a multi-object spectrograph (MOS) for the European Extremely Large
Telescope (E-ELT). These efforts span the full range of E-ELT science
and include input from a broad cross-section of astronomers across
the ESO partner countries. In this contribution we summarise the key
cases relating to studies of high-redshift galaxies, galaxy evolution,
and stellar populations, with a more expansive presentation of a
new case relating to detection of exoplanets in stellar clusters. A
general requirement is the need for two observational modes to best
exploit the large (>=40 arcmin2) patrol field of the
E-ELT. The first mode (`high multiplex') requires integrated-light
(or coarsely resolved) optical/near-IR spectroscopy of >100
objects simultaneously. The second (`high definition'), enabled by
wide-field adaptive optics, requires spatially-resolved, near-IR of
>10 objects/sub-fields. Within the context of the conceptual study
for an ELT-MOS called MOSAIC, we summarise the toplevel requirements
from each case and introduce the next steps in the design process.
Title: A New Ground-Based Network for Synoptic Solar Observations:
The Solar Physics Research Integrated Network Group (SPRING)
Authors: Hill, Frank; Roth, Markus; Thompson, Michael; Gusain, Sanjay
Bibcode: 2014AAS...22412354H
Altcode:
SPRING is a project to develop a geographically distributed network
of instrumentation to obtain synoptic solar observations. Building
on the demonstrated success of networks to provide nearly-continuous
long-term data for helioseismology, SPRING will provide data for a wide
range of solar research areas. Scientific objectives include internal
solar dynamics and structure; wave transport in the solar atmosphere;
the evolution of the magnetic field over the activity cycle; irradiance
fluctuations; and space weather origins. Anticipated data products
include simultaneous full-disk multi-wavelength Doppler and vector
magnetic field images; filtergrams in H-Alpha, CaK, and white light;
and PSPT-type irradiance support. The data will be obtained with a duty
cycle of around 90% and at a cadence no slower than one minute. The
current concept is a multi-instrument platform installed in at least
six locations, and which will also provide context information for
large-aperture solar telescopes such as EST and the DKIST. There is
wide support for the idea within the EU and the US solar research
communities. The project is in the early planning stages, and we are
open to and looking for participants in the science and instrument
definition.
Title: An Upper Bound from Helioseismology on the Stochastic
Background of Gravitational Waves
Authors: Siegel, Daniel M.; Roth, Markus
Bibcode: 2014ApJ...784...88S
Altcode: 2014arXiv1401.6888S
The universe is expected to be permeated by a stochastic background of
gravitational radiation of astrophysical and cosmological origin. This
background is capable of exciting oscillations in solar-like
stars. Here we show that solar-like oscillators can be employed as
giant hydrodynamical detectors for such a background in the μHz to
mHz frequency range, which has remained essentially unexplored until
today. We demonstrate this approach by using high-precision radial
velocity data for the Sun to constrain the normalized energy density
of the stochastic gravitational-wave background around 0.11 mHz. These
results open up the possibility for asteroseismic missions like CoRoT
and Kepler to probe fundamental physics.
Title: KIC 6761539, a fast rotating γ Dor - δ Sct hybrid star
Authors: Herzberg, W.; Corre, D.; Uytterhoeven, K.; Roth, M.
Bibcode: 2014IAUS..301..419H
Altcode:
KIC 6761539 is one of many fast rotating γ Doradus - δ Scuti hybrid
pulsators. A search for possible regularities in the frequency spectrum
is performed and a first stellar model is presented.
Title: Global Helioseismic Evidence for a Deeply Penetrating Solar
Meridional Flow Consisting of Multiple Flow Cells
Authors: Schad, A.; Timmer, J.; Roth, M.
Bibcode: 2013ApJ...778L..38S
Altcode: 2013arXiv1311.7623S
We use a novel global helioseismic analysis method to infer the
meridional flow in the deep Solar interior. The method is based
on the perturbation of eigenfunctions of Solar p modes due to
meridional flow. We apply this method to time series obtained from
Dopplergrams measured by the Michelson Doppler Imager aboard the
Solar and Heliospheric Observatory covering the observation period
2004-2010. Our results show evidence that the meridional flow reaches
down to the base of the convection zone. The flow profile has a complex
spatial structure consisting of multiple flow cells distributed in
depth and latitude. Toward the Solar surface, our results are in good
agreement with flow measurements from local helioseismology.
Title: Where to go from here: The Future of Helio- and
Astero-seismology
Authors: Hill, F.; Baldner, C. S.; García, R. A.; Roth, M.;
Schunker, H.
Bibcode: 2013ASPC..478..401H
Altcode:
While this conference is partly a look back over 50 years of
helioseismology, we also look forward into the future. Upcoming
paths of research in the near-term include understanding the effects
due to strong surface magnetic fields, including mode conversion, in
the solar atmosphere and how they affect subsurface inferences; the
place of the Sun in the asteroseismic universe, and the relationship
of subsurface dynamics and solar activity as forecast tools for
space weather. These paths will motivate new technical approaches of
multi-height/multi-wavelength solar observations; numerical models
of wave propagation in magnetized plasmas; further understanding of
systematic errors; and combined analyses of vector magnetic field
measurements and helioseismic data. The next major programmatic
steps will be the advent of multi-viewpoint solar space missions,
and the development of a new multi-purpose solar synoptic observing
network on the ground. For asteroseismology, the PLATO mission and
the ground-based SONG program will provide a wealth of new data.
Title: NIR Spectroscopy of PSN J12015272-1852183 with FIRE
Authors: Marion, G. H.; Hsiao, E. Y.; Roth, M.; Silverman, J. M.;
Wheeler, J. C.; Vinko, J.
Bibcode: 2013ATel.5167....1M
Altcode:
We report that a near-infrared spectrum (range 800-2400 nm) of the
supernova in NGC 4308 (= PSN J12015272-1852183) was obtained on June 24
UT with the FoldedPort Infrared Echellette (FIRE) spectrograph on the
6.5-m Magellan Baade Telescope. Inspection of the spectrum reveals no
features that are associated with Paschen series lines or He I lines
at this phase.
Title: The energy spectrum of cosmic rays at the highest energies
Authors: Dawson, Bruce R.; Mariş, Ioana C.; Roth, Markus; Salamida,
Francesco; Abu-Zayyad, Tareq; Ikeda, Daisuke; Ivanov, Dmitri;
Tsunesada, Yoshiki; Pravdin, Mikhail I.; Sabourov, Artem V.
Bibcode: 2013EPJWC..5301005D
Altcode: 2013arXiv1306.6138D
One of several working groups established for this workshop was charged
with examining results and methods associated with the UHECR energy
spectrum. We summarize the results of our discussions, which include
a better understanding of the analysis choices made by groups and
their motivation. We find that the energy spectra determined by the
larger experiments are consistent in normalization and shape after
energy scaling factors are applied. Those scaling factors are within
systematic uncertainties in the energy scale, and we discuss future
work aimed at reducing these systematics.
Title: A New Multi-Wavelength Synoptic Network for Solar Physics
and Space Weather
Authors: Hill, Frank; Roth, Markus; Thompson, Michael
Bibcode: 2013EGUGA..1511892H
Altcode:
Continuous solar observations are important for many research topics
in solar physics, such as magnetic field evolution, flare and CME
characteristics, and p-mode oscillation measurements. In addition,
space weather operations require constant streams of solar data as
input. The deployment of a number of identical instruments around
the world in a network has proven to be a very effective strategy for
obtaining nearly continuous solar observations. The financial costs of
a network are 1-2 orders of magnitude lower than space-based platforms;
network instrumentation can be easily accessed for maintenance and
upgrades; and telemetry bandwidth is readily available. Currently,
there are two solar observing networks with consistent instruments:
BiSON and GONG, both designed primarily for helioseismology. In
addition, GONG has been augmented with continual magnetic field
measurements and H-alpha imagery, with both being used for space
weather operational purposes. However, GONG is now 18 years old and
getting increasingly more challenging to maintain. There are also at
least three scientific motivations for a multi-wavelength network:
Recent advances in helioseismology have demonstrated the need for
multi-wavelength observations to allow more accurate interpretation
of the structure and dynamics below sunspots. Vector magnetometry
would greatly benefit from multi-wavelength observations to provide
height information and resolve the azimuthal ambiguity. Finally,
space weather operations always need a consistent reliable source of
continual solar data. This presentation will outline the scientific
need for a multi-wavelength network, and discuss some concepts for
the design of the instrumentation. A workshop on the topic will be
held in Boulder this April.
Title: LOPES 3D reconfiguration and first measurements
Authors: Huber, D.; Apel, W. D.; Arteaga, J. C.; Bähren, L.; Bekk,
K.; Bertaina, M.; Biermann, P. L.; Blümer, J.; Bozdog, H.; Brancus,
I. M.; Buchholz, P.; Cantoni, E.; Chiavassa, A.; Daumiller, K.; de
Souza, V.; Di Pierro, F.; Doll, P.; Engel, R.; Falcke, H.; Finger,
M.; Fuchs, B.; Fuhrmann, D.; Gemmeke, H.; Grupen, C.; Haungs, A.;
Heck, D.; Hörandel, J. R.; Horneffer, A.; Huege, T.; Isar, P. G.;
Kampert, K. -H.; Kang, D.; Krömer, O.; Kuijpers, J.; Link, K.;
Luczak, P.; Ludwig, M.; Mathes, H. J.; Melissas, M.; Morello, C.;
Oehlschläger, J.; Palmieri, N.; Pierog, T.; Rautenberg, J.; Rebel,
H.; Roth, M.; Rühle, C.; Saftoiu, A.; Schieler, H.; Schmidt, A.;
Schröder, F. G.; Sima, O.; Toma, G.; Trinchero, G. C.; Weindl, A.;
Wochele, J.; Wommer, M.; Zabierowski, J.; Zensus, J. A.
Bibcode: 2013arXiv1303.7070H
Altcode:
The Radio detection technique of high-energy cosmic rays is based on the
radio signal emitted by the charged particles in an air shower due to
their deflection in the Earth's magnetic field. The LOPES experiment at
Karlsruhe Institute of Technology, Germany with its simple dipoles made
major contributions to the revival of this technique. LOPES is working
in the frequency range from 40 to 80 MHz and was reconfigured several
times to improve and further develop the radio detection technique. In
the current setup LOPES consists of 10 tripole antennas which measure
the complete electric field vector of the radio emission from cosmic
rays. LOPES is the first experiment measuring all three vectorial
components at once and thereby gaining the full information about the
electric field vector and not only a two-dimensional projection. Such
a setup including also measurements of the vertical electric field
component is expected to increase the sensitivity to inclined showers
and help to advance the understanding of the emission mechanism. We
present the reconfiguration and calibration procedure of LOPES 3D and
discuss first measurements.
Title: LOPES 3D - vectorial measurements of radio emission from
cosmic ray induced air showers
Authors: Apel, W. D.; Arteaga, J. C.; Bähren, L.; Bekk, K.;
Bertaina, M.; Biermann, P. L.; Blümer, J.; Bozdog, H.; Brancus,
I. M.; Chiavassa, A.; Daumiller, K.; de Souza, V.; Di Pierro, F.;
Doll, P.; Engel, R.; Falcke, H.; Fuchs, B.; Fuhrmann, D.; Gemmeke,
H.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel, J. R.; Horneffer,
A.; Huber, D.; Huege, T.; Isar, P. G.; Kampert, K. -H.; Kang, D.;
Krömer, O.; Kuijpers, J.; Link, K.; Luczak, P.; Ludwig, M.; Mathes,
H. J.; Melissas, M.; Morello, C.; Oehlschläger, J.; Palmieri, N.;
Pierog, T.; Rautenberg, J.; Rebel, H.; Roth, M.; Rühle, C.; Saftoiu,
A.; Schieler, H.; Schmidt, A.; Schröder, F. G.; Sima, O.; Toma, G.;
Trinchero, G. C.; Weindl, A.; Wochele, J.; Zabierowski, J.; Zensus,
J. A.
Bibcode: 2013arXiv1303.7080A
Altcode:
LOPES 3D is able to measure all three components of the electric
field vector of the radio emission from air showers. This allows
a better comparison with emission models. The measurement of the
vertical component increases the sensitivity to inclined showers. By
measuring all three components of the electric field vector LOPES 3D
demonstrates by how much the reconstruction accuracy of primary cosmic
ray parameters increases. Thus LOPES 3D evaluates the usefulness of
vectorial measurements for large scale applications.
Title: The Quasi-biennial Periodicity as a Window on the Solar
Magnetic Dynamo Configuration
Authors: Simoniello, R.; Jain, K.; Tripathy, S. C.; Turck-Chièze,
S.; Baldner, C.; Finsterle, W.; Hill, F.; Roth, M.
Bibcode: 2013ApJ...765..100S
Altcode: 2012arXiv1210.6796S
Manifestations of the solar magnetic activity through periodicities
of about 11 and 2 years are now clearly seen in all solar activity
indices. In this paper, we add information about the mechanism driving
the 2-year period by studying the time and latitudinal properties of
acoustic modes that are sensitive probes of the subsurface layers. We
use almost 17 years of high-quality resolved data provided by the Global
Oscillation Network Group to investigate the solar cycle changes in
p-mode frequencies for spherical degrees l from 0 to 120 and 1600 μHz
<=ν <= 3500 μHz. For both periodic components of solar activity,
we locate the origin of the frequency shift in the subsurface layers
and find evidence that a sudden enhancement in amplitude occurs in just
the last few hundred kilometers. We also show that, in both cases, the
size of the shift increases toward equatorial latitudes and from minimum
to maximum solar activity, but, in agreement with previous findings,
the quasi-biennial periodicity (QBP) causes a weaker shift in mode
frequencies and a slower enhancement than that caused by the 11-year
cycle. We compare our observational findings with the features predicted
by different models, that try to explain the origin of this QBP and
conclude that the observed properties could result from the beating
between a dipole and quadrupole magnetic configuration of the dynamo.
Title: Interpretation of the Microwave Signal found for High Energy
Air Showers Observed with CROME
Authors: Werner, F.; Engel, R.; Mída, R. Sˇ; Arteaga-Velázquez,
J. C.; Bekk, K.; Bertaina, M.; Blümer, J.; Bozdog, H.; Chiavassa,
I. M. Brancus A.; Cossavella, F.; di Pierro, F.; Doll, P.; Fuchs,
B.; Fuhrmann, D.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel, J. R.;
Huber, D.; Huege, T.; Kampert, K. -H.; Kang, D.; Klages, H.; Kleifges,
M.; Krömer, O.; Link, K.; Łuczak, P.; Ludwig, M.; Mathes, H. J.;
Mayer, H. J.; Mathys, S.; Melissas, M.; Morello, C.; Neunteufel, P.;
Oehlschläger, J.; Palmieri, N.; Pekala, J.; Pierog, T.; Rautenberg,
J.; Rebel, H.; Riegel, M.; Roth, M.; Salamida, F.; Schieler, H.; Schoo,
S.; Schröder, F. G.; Sima, O.; Stasielak, J.; Toma, G.; Trinchero,
G. C.; Unger, M.; Weber, M.; Weindl, A.; Wilczyński, H.; Will, M.;
Wochele, J.; Zabierowski, J.
Bibcode: 2013ICRC...33.1808W
Altcode:
Microwave radiation from high-energy air showers has been observed
in the Cband (3.4-4.2GHz)with the CROME (Cosmic-Ray Observation via
Microwave Emission) setup. The general properties of the detected
air showers and important features of the event distributions are
described. The compatibility of the measured GHz signals with different
hypotheses is discussed. It is shown that isotropic, unpolarized
radiation is disfavored as the dominant emission mechanism in forward
direction compared with emission due to the geomagnetic effect and
charge excess variation.
Title: Vectorial Radio Interferometry with LOPES 3D
Authors: Huber, D.; Apel, W. D.; Arteaga-Velázquez, J. C.; Bähren,
L.; Bekk, K.; Bertaina, M.; Biermann, P. L.; Blümer, J.; Bozdog,
H.; Brancus, I. M.; Cantoni, E.; Chiavassa, A.; Daumiller, K.; de
Souza, V.; di Pierro, F.; Doll, P.; Engel, R.; Falcke, H.; Fuchs,
B.; Fuhrmann, D.; Gemmeke, H.; Grupen, C.; Haungs, A.; Heck, D.;
Hörandel, J. R.; Horneffer, A.; Huege, T.; Isar, P. G.; Kampert,
K. -H.; Kang, D.; Krömer, O.; Kuijpers, J.; Link, K.; Łuczak, P.;
Ludwig, M.; Mathes, H. J.; Melissas, M.; Morello, C.; Oehlschläger,
J.; Palmieri, N.; Pierog, T.; Rautenberg, J.; Rebel, H.; Roth,
M.; Rühle, C.; Saftoiu, A.; Schieler, H.; Schmidt, A.; Schröder,
F. G.; Sima, O.; Toma, G.; Trinchero, G. C.; Weindl, A.; Wochele,
J.; Zabierowski, J.; Zensus, J. A.
Bibcode: 2013ICRC...33.1643H
Altcode: 2013arXiv1308.2512H
One successful detection technique for high-energy cosmic rays is
based on the radio signal emitted by the charged particles in an
air shower [1]. The LOPES experiment [2] at Karlsruhe Institute of
Technology, Germany, has made major contributions to the evolution of
this technique. LOPES was reconfigured several times to improve and
further develop the radio detection technique. In the latest setup
LOPES consisted of 10 tripole antennas. With this, LOPES 3D [3] was
the first cosmic ray experiment measuring all three vectorial field
components at once and thereby gaining the full information about the
electric field vector. We present an analysis based on the data taken
with special focus on the benefits of a direct measurement of the
vertical polarization component. We demonstrate that by measuring all
polarization components the detection and reconstruction efficiency
is increased and noisy single channel data can be reconstructed by
utilising the information from the other two channels of one antenna
station.
Title: A Comparison of LOPES Lateral Distributions of the Air-shower
Radio Signal with REAS 3.11 and CoREAS Simulations
Authors: Schröder, F. G.; Apel, W. D.; Arteaga-Velázquez, J. C.;
Bähren, L.; Bekk, K.; Bertaina, M.; Biermann, P. L.; Blümer, J.;
Bozdog, H.; Brancus, I. M.; Cantoni, E.; Chiavassa, A.; Daumiller,
K.; de Souza, V.; di Pierro, F.; Doll, P.; Engel, R.; Falcke, H.;
Fuchs, B.; Fuhrmann, D.; Gemmeke, H.; Grupen, C.; Haungs, A.; Heck,
D.; Hörandel, J. R.; Horneffer, A.; Huber, D.; Huege, T.; Isar,
P. G.; Kampert, K. -H.; Kang, D.; Krömer, O.; Kuijpers, J.; Link,
K.; Łuczak, P.; Ludwig, M.; Mathes, H. J.; Melissas, M.; Morello,
C.; Oehlschläger, J.; Palmieri, N.; Pierog, T.; Rautenberg, J.;
Rebel, H.; Roth, M.; Rühle, C.; Saftoiu, A.; Schieler, H.; Schmidt,
A.; Sima, O.; Toma, G.; Trinchero, G. C.; Weindl, A.; Wochele, J.;
Zabierowski, J.; Zensus, J. A.
Bibcode: 2013ICRC...33.1589S
Altcode:
We compare radio lateral distributions measured with LOPES to REAS
3.11 and CoREAS simulations of the radio emission. These simulation
codes describe the measured radio signal significantly better than
previous versions of REAS, which did not yet include the refractive
index of air. The refractive index changes the coherence conditions
of the radio emission. This causes flatter lateral distributions at
LOPES distances (up to a few 100 m). In a few events the amplitude
even falls towards the shower axis: a behavior which we observe both
in simulations and measurements. Generally, REAS 3.11 and CoREAS can
reproduce the measured slope of the lateral distributions within
the uncertainties. With respect to the absolute amplitude of the
radio signal, however, there is a difference between REAS 3.11 and
CoREAS. The amplitude predicted by REAS 3.11 is approximately twice as
large as the one predicted by CoREAS in frequency range (43 - 74 MHz)
of LOPES, and REAS 3.11 is closer to the LOPES measurements. Overall,
the comparison shows that the understanding of the radio emission has
clearly advanced in the last years. It confirms that in addition to the
dominant geomagnetic and the sub-dominant Askaryan effect (charge excess
variation) the refractive index of the air plays an important role.
Title: Comparison of LOPES data and CoREAS Simulations using a Full
Detector Simulation
Authors: Link, K.; Apel, W. D.; Arteaga-Velazquez, J. C.; Bahren,
L.; Bekk, K.; Bertaina, M.; Biermann, P. L.; Blumer, J.; Bozdog,
H.; Brancus, I. M.; Cantoni, E.; Chiavassa, A.; Daumiller, K.; De
Souza, V.; Di Pierro, F.; Doll, P.; Engel, R.; Falcke, H.; Fuchs, B.;
Fuhrmann, D.; Gemmeke, H.; Grupen, C.; Haungs, A.; Heck, D.; Horandel,
J. R.; Horneffer, A.; Huber, D.; Huege, T.; Isar, P. G.; Kampert,
K. -H.; Kang, D.; Kromer, O.; Kuijpers, J.; Luczak, P.; Ludwig, M.;
Mathes, H. J.; Melissas, M.; Morello, C.; Oehlschlager, J.; Palmieri,
N.; Pierog, T.; Rautenberg, J.; Rebel, H.; Roth, M.; Rühle, C.;
Saftoiu, A.; Schieler, H.; Schmidt, A.; Schroder, F. G.; Sima, O.;
Toma, G.; Trinchero, G. C.; Weindl, A.; Wochele, J.; Zabierowski,
J.; Zensus, J. A.
Bibcode: 2013ICRC...33.1705L
Altcode: 2013arXiv1308.2523L
The LOPES experiment at the Karisruhe Tnstitute of Technology,
Germany, has been measuring radio emission of air showers for almost 10
years. For a better understanding of the emission process a detailed
comparison of data with simulations is necessary. This is possible
using a newly developed detector simulation including all LOPES
detector components. After propagating a simulated event through
this full detector simulation a standard LOPES like event file is
written. LOPES data and CoREAS simulations can then be treated equally
and the same analysis software can be applied to both. This gives the
opportunity to compare data and simulations directly. Furthermore, the
standard analysis software can be used with simulations which provide
the possibility to check the accuracy regarding reconstruction of
air shower parameters. We point out the advantages and present first
results using such a full LOPES detector simulation. A comparison of
LOPES data and the Monte Carlo code CoREAS based on an analysis using
this detector simulation is shown.
Title: On the Importance of the Energy Resolution for Identifying
Sources of UHECR
Authors: Brummel, V.; Engel, R.; Roth, M.
Bibcode: 2013ICRC...33..679B
Altcode:
No abstract at ADS
Title: Investigation on the Energy and Mass Composition of Cosmic
Rays Using LOPES Radio Data
Authors: Palmieri, N.; Apel, W. D.; Arteaga-Velázquez, J. C.;
Bähren, L.; Bekk, K.; Bertaina, M.; Biermann, P. L.; Blümer, J.;
Bozdog, H.; Brancus, I. M.; Cantoni, E.; Chiavassa, A.; Daumiller,
K.; de Souza, V.; di Pierro, F.; Doll, P.; Engel, R.; Falcke, H.;
Fuchs, B.; Fuhrmann, D.; Gemmeke, H.; Grupen, C.; Haungs, A.; Heck,
D.; Hörandel, J. R.; Horneffer, A.; Huber, D.; Huege, T.; Isar,
P. G.; Kampert, K. -H.; Kang, D.; Krömer, O.; Kuijpers, J.; Link,
K.; Łuczak, P.; Ludwig, M.; Mathes, H. J.; Melissas, M.; Morello,
C.; Oehlschläger, J.; Pierog, T.; Rautenberg, J.; Rebel, H.; Roth,
M.; Rühle, C.; Saftoiu, A.; Schieler, H.; Schmidt, A.; Schröder,
F. G.; Sima, O.; Toma, G.; Trinchero, G. C.; Weindl, A.; Wochele,
J.; Zabierowski, J.; Zensus, J. A.; Lopes Collaboration
Bibcode: 2013ICRC...33..360P
Altcode: 2013arXiv1309.2410P
The sensitivity to the mass composition as well as the reconstruction of
the energy of the primary particle are explored here by leveraging the
features of the radio lateral distribution function. For the purpose
of this analysis, a set of events measured with the LOPES experiment
is reproduced with the latest CoREAS radio simulation code. Based on
simulation predictions, a method which exploits the slope of the radio
lateral distribution function is developed (Slope Method) and directly
applied on measurements. As a result, the possibility to reconstruct
both the energy and the Xmax, i.e. depth of the shower maximum, of
the cosmic ray air shower using radio data and achieving relatively
small uncertainties is presented.
Title: Detection of a Change of Slope in the Spectrum of Heavy Mass
Cosmic Rays Primaries by the Kascade-Grande Experiment
Authors: Chiavassa, A.; Apel, W. D.; Arteaga-Velázquez, J. C.;
Bekk, K.; Bertaina, M.; Blümer, J.; Bozdog, H.; Brancus, I. M.;
Cantoni, E.; Cossavella, F.; Daumiller, K.; de Souza, V.; Di Pierro,
F.; Doll, P.; Engel, R.; Engler, J.; Finger, M.; Fuchs, B.; Fuhrmann,
D.; Garino, F.; Gils, H. J.; Glasstetter, R.; Grupen, C.; Haungs, A.;
Heck, D.; Hörandel, J. R.; Huber, D.; Huege, T.; Kampert, K. -H.;
Kang, D.; Klages, H. O.; Link, K.; Łuczak, P.; Ludwig, M.; Mathes,
H. J.; Mayer, H. J.; Melissas, M.; Milke, J.; Mitrica, B.; Morello,
C.; Oehlschläger, J.; Ostapchenko, S.; Palmieri, N.; Petcu, M.;
Pierog, T.; Rebel, H.; Roth, M.; Schieler, H.; Schoo, S.; Schröder,
F. G.; Sima, O.; Toma, G.; Trinchero, G. C.; Ulrich, H.; Weindl, A.;
Wochele, J.; Wommer, M.; Zabierowski, J.
Bibcode: 2013AcPol..53..727C
Altcode:
No abstract at ADS
Title: Ground-based multi-color photometry of the γ Doradus-δ
Scuti hybrid star KIC 6761539
Authors: Herzberg, W.; Uytterhoeven, K.; Roth, M.
Bibcode: 2012AN....333.1077H
Altcode:
We present a preliminary analysis of the first three nights of
multi-color photometric data for a γ Doradus-δ Scuti hybrid star
(KIC 6761539) that is also being observed with the Kepler space
telescope. We find that up to four (depending on the filter) of the
highest amplitude modes, whose frequencies could be determined from
Kepler data, are visible from the ground. Our goal is to use the
multi-color information for mode identification, but this will only
be possible with a longer time series. A multi-color photometric
multi-site campaign is currently ongoing for this purpose.
Title: The non-adiabatic high-degree f-mode
Authors: Zhugzhda, Y. D.; Roth, M.
Bibcode: 2012AN....333..931Z
Altcode:
The current theory of the high-degree solar f-mode based on an
adiabatic approximation is in contradiction with observations,
since the f-mode is visible in intensity oscillations of the Sun. As
a possible solution we present an universal analytical treatment
for a non-adiabatic f-mode. This non-adiabatic theory provides the
explanation of brightness oscillations due to the f-mode. We find that
the non-adiabatic effects do not lead to a damping of the f-mode since
the dispersion relation is the same as in the adiabatic approximation.
Title: On the feasibility of employing solar-like oscillators as
detectors for the stochastic background of gravitational waves
Authors: Siegel, D. M.; Roth, M.
Bibcode: 2012AN....333..978S
Altcode: 2014arXiv1401.6883S
We present a hydrodynamic model that describes excitation of linear
stellar oscillations by a stochastic background of gravitational waves
(SBGW) of astrophysical and cosmological origin. We find that this
excitation mechanism is capable of generating solar g-mode amplitudes
close to or comparable with values expected from excitation by turbulent
convection, which is considered to be the main driving force for
solar-like oscillations. A method is presented that places direct upper
bounds on the SBGW in a frequency range, in which the SBGW is expected
to contain rich astrophysical information. Employing estimates for
solar g-mode amplitudes, the proposed method is demonstrated to have
the potential to compete with sensitivities reached by gravitational
wave experiments in other frequency ranges.
Title: Editor's note: The Modern Era of Helio- and Asteroseismology
Authors: Roth, Markus
Bibcode: 2012AN....333..913R
Altcode:
No abstract at ADS
Title: Seismic comparison of the 11- and 2-year cycle signatures in
the Sun
Authors: Simoniello, R.; Jain, K.; Tripathy, S. C.; Turck-Chiéze,
S.; Finsterle, W.; Roth, M.
Bibcode: 2012AN....333.1018S
Altcode: 2012arXiv1210.6182S
The solar magnetic activity consists of two periodic components: the
main cycle with a period of 11 yr and a shorter cycle with a period
of ≈2 yr. The origin of this second periodicity is still not well
understood. We use almost 15 years of long high-quality resolved data
provided by the Global Oscillation Network Group (GONG) to investigate
the solar cycle changes in p-mode oscillations with spherical degree
ℓ= 0-120 and in the range of 1600 \muHz \le\nu\le 3500 \muHz. For both
periodic components of solar magnetic activity our findings locate the
origin of the frequency shift in the subsurface layers with a sudden
enhancement in the amplitude of the shift in the last few hundred
kilometers. We also show that the size of the shift increases towards
equatorial latitudes and from minimum to maximum of solar activity. On
the other hand, the signatures of the 2-yr cycle differ from the one
of the 11-yr cycle in the magnitude of the shift, as the 2-yr cycle
causes a weaker shift in mode frequencies and a slower enhancement in
the last few hundred kilometers. Based on these findings we speculate
that a possible physical mechanism behind the quasi biennial periodicity
(QBP) could be the beating between different dynamo modes (dipole and
quadrupole mode).
Title: Supernova 2012hr in Pgc 18880 = Psn J06213846-5942506
Authors: Drescher, C.; Marples, P.; Brimacombe, J.; Milisavljevic, D.;
Fesen, R.; Pickering, T.; Kniazev, A.; Morrell, N.; Phillips, M. M.;
Contreras, C.; Roth, M.; Hsiao, E. Y.; Marion, G. H.; Stritzinger, M.
Bibcode: 2012CBET.3346....1D
Altcode: 2012CBET.3346A...1D
Colin Drescher, Calamvale, Queensland, Australia, reports the discovery
of an apparent supernova (red mag 14.8) by Peter Marples (Loganholme,
Qld.) on a 30-s unfiltered CCD image (limiting mag 17.5) taken on
Dec. 16.53 UT using a 30-cm Meade LX200R reflector (+ Starlight Xpress
camera) in the course of the Backyard Observatory Supernova Search
(BOSS). The new object is located at R.A. = 6h21m38s.46, Decl. =
-59d42'50".6 (equinox 2000.0; measured by Drescher), which is 2"
west and 94" north of the nucleus of the presumed host galaxy, ESO
121-26 = PGC 18880. Nothing is visible at this position on Digitized
Sky Survey red and infrared images (limiting red magnitude >
19). The variable was designated PSN J06213846-5942506 when it was
posted at the Central Bureau's TOCP webpage and is here designated
SN 2012hr based on the spectroscopic confirmation reported
below. Joseph Brimacombe, Cairns, Australia, reports magnitude
14.7 and position end figures 38s.49, 51".0 from CCD exposures
taken on Dec. 18.565 with a 41-cm RCOS telescope with an infrared
filter (bandpass > 700 nm); his images are posted at website URL
http://www.flickr.com/photos/43846774@N02/8286710122/. D. Milisavljevic,
Harvard-Smithsonian Center for Astrophysics; R. Fesen, Dartmouth
College; and T. Pickering and A. Kniazev, South African Astronomical
Observatory and Southern African Large Telescope, report that
low-dispersion spectra (range 330-890 nm), obtained on Dec. 19.8 UT
with the 10-m SALT telescope (+ RSS), show PSN J06213846-5942506 =
SN 2012hr to be a young type-Ia supernova. Cross-correlation with a
library of supernova spectra using the "Supernova Identification" code
(SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows a reasonable match
to SN 2004fu about a week before maximum light. After removal of the
host-galaxy (ESO 121-26) redshift of z = 0.007562 (via NED; Koribalski
et al. 2004, A.J. 128, 16), the absorption minimum of the Si II 635.5-nm
line is found to be blueshifted by about -13700 km/s. N. Morrell,
M. M. Phillips, C. Contreras, M. Roth, and E. Y. Hsiao, Las Campanas
Observatory; G. H. Marion, Harvard-Smithsonian Center for Astrophysics;
and M. Stritzinger, Aarhus University, on behalf of the Carnegie
Supernova Project, report that a near-infrared spectrum (range 800-2400
nm) of PSN J06213846-5942506 = SN 2012hr was obtained on Dec. 20.20 UT
with the FoldedPort Infrared Echellette (FIRE) spectrograph on the 6.5-m
Magellan Baade Telescope. The spectrum shows that 2012hr is a type-Ia
supernova approximately a week before maximum light. The near-infrared
spectrum is similar to that of SN 2003W at eight days before maximum
(Marion et al. 2009, A.J. 138, 727). Adopting a redshift of z = 0.008
for the presumed host galaxy (PGC 18880), the velocity of the Mg II
1092.7-nm absorption feature is measured to be approximately 12200 km/s.
Title: PSN J06213846-5942506 is a young type-Ia supernova
Authors: Morrell, N.; Phillips, M. M.; Contreras, C.; Roth, M.; Hsiao,
E. Y.; Marion, G. H.; Stritzinger, M.
Bibcode: 2012ATel.4663....1M
Altcode:
We report that a near-infrared spectrum (range 800-2400 nm) of PSN
J06213846-5942506 was obtained on Dec. 20.20 UT with the Folded-port
Infrared Echellette (FIRE) spectrograph on the 6.5-m Magellan
Baade Telescope. The spectrum shows that it is a type-Ia supernova
approximately a week before maximum light. The near-infrared spectrum
is similar to that of SN 2003W at eight days before maximum (Marion
et al....
Title: Measuring the solar meridional flow from perturbations of
eigenfunctions of global oscillations
Authors: Schad, A.; Timmer, J.; Roth, M.
Bibcode: 2012AN....333..991S
Altcode:
We present a new concept to infer the meridional flow in the deep solar
interior from global oscillation data. This concept is based on the
estimation of the coupling strengths of p-mode eigenfunctions mediated
by the meridional flow. We illustrate the performance of the method
using simulations and present first inversion results of a large-scale
flow component of the meridional flow obtained from MDI data.
Title: Kappa-effect and brightness oscillations of stars
Authors: Zhugzhda, Y. D.; Roth, M.; Herzberg, W.
Bibcode: 2012AN....333..926Z
Altcode:
In this paper the theory of visibility and darkening functions for the
brightness oscillations of stars is outlined. For this the non-grey
approximation is used and the effect of opacity disturbances on
stellar brightness oscillations is explored for different types of
stars. An explanation of the Procyon paradox is proposed. Special
features of the brightness oscillations are discussed. The effect
of opacity fluctuations on the damping of p-mode oscillations is
considered. Furthermore, the photospheric kappa-mechanism is discussed.
Title: Mapping luminous blue compact galaxies with
VIRUS-P. Morphology, line ratios, and kinematics
Authors: Cairós, L. M.; Caon, N.; García Lorenzo, B.; Kelz, A.;
Roth, M.; Papaderos, P.; Streicher, O.
Bibcode: 2012A&A...547A..24C
Altcode: 2012arXiv1209.0310C
Context. Blue compact galaxies (BCG) are narrow emission-line
systems that undergo a violent burst of star formation. They are
compact, low-luminosity galaxies, with blue colors and low chemical
abundances, which offer us a unique opportunity to investigate
collective star formation and its effects on galaxy evolution in
a relatively simple, dynamically unperturbed environment. Spatially
resolved spectrophotometric studies of BCGs are essential for a better
understanding of the role of starburst-driven feedback processes on
the kinematical and chemical evolution of low-mass galaxies near
and far.
Aims: We carry out an integral field spectroscopy
(IFS) study of a sample of luminous BCGs, with the aim to probe the
morphology, kinematics, dust extinction, and excitation mechanisms of
their warm interstellar medium (ISM).
Methods: We obtained IFS
data for five luminous BCGs with VIRUS-P, the prototype instrument for
the Visible Integral Field Replicable Unit Spectrograph, attached to
the 2.7 m Harlan J. Smith Telescope at the McDonald Observatory. VIRUS-P
consists of a square array of 247 optical fibers, which covers a 109″
× 109″ field of view, with a spatial sampling of 4farcs2 and a 0.3
filling factor. We observed in the 3550-5850 Å spectral range, with
a resolution of 5 Å FWHM. From these data we built two-dimensional
maps of the continuum and the most prominent emission-lines ([O ii]
λ3727, Hγ, Hβ and [O iii] λ5007), and investigated the morphology
of diagnostic emission-line ratios and the extinction patterns in the
ISM as well as stellar and gas kinematics. Additionally, from integrated
spectra we inferred total line fluxes and luminosity-weighted extinction
coefficients and gas-phase metallicities.
Results: All galaxies
exhibit an overall regular morphology in the stellar continuum, while
their warm ISM morphology is more complex: in II Zw 33 and Mrk 314,
the star-forming regions are aligned along a chain-structure; Haro
1, NGC 4670 and III Zw 102 display several salient features, such
as extended gaseous filaments and bubbles. A significant intrinsic
absorption by dust is present in all galaxies, the most extreme case
being III Zw 102. Our data reveal a plethora of kinematical patterns,
from overall regular gas and stellar rotation to complex velocity
fields produced by structurally and kinematically distinct components.
Title: Gamma-Ray Observations of the Orion Molecular Clouds with
the Fermi Large Area Telescope
Authors: Ackermann, M.; Ajello, M.; Allafort, A.; Antolini, E.;
Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol,
K.; Bellazzini, R.; Berenji, B.; Blandford, R. D.; Bloom, E. D.;
Bonamente, E.; Borgland, A. W.; Bottacini, E.; Brandt, T. J.; Bregeon,
J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.;
Cameron, R. A.; Caraveo, P. A.; Cecchi, C.; Chekhtman, A.; Chiang, J.;
Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; D'Ammando, F.;
de Angelis, A.; de Palma, F.; Dermer, C. D.; Silva, E. do Couto e.;
Drell, P. S.; Drlica-Wagner, A.; Enoto, T.; Falletti, L.; Favuzzi,
C.; Fegan, S. J.; Ferrara, E. C.; Focke, W. B.; Fukazawa, Y.; Fukui,
Y.; Fusco, P.; Gargano, F.; Gasparrini, D.; Germani, S.; Giglietto,
N.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Guiriec,
S.; Hadasch, D.; Hanabata, Y.; Harding, A. K.; Hayashida, M.; Hayashi,
K.; Horan, D.; Hou, X.; Hughes, R. E.; Jackson, M. S.; Jóhannesson,
G.; Johnson, A. S.; Kamae, T.; Katagiri, H.; Kataoka, J.; Kerr,
M.; Knödlseder, J.; Kuss, M.; Lande, J.; Larsson, S.; Lee, S. -H.;
Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Makishima,
K.; Mazziotta, M. N.; Mehault, J.; Mitthumsiri, W.; Moiseev, A. A.;
Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia,
S.; Nakamori, T.; Naumann-Godo, M.; Nishino, S.; Norris, J. P.;
Nuss, E.; Ohno, M.; Ohsugi, T.; Okumura, A.; Orienti, M.; Orlando,
E.; Ormes, J. F.; Ozaki, M.; Paneque, D.; Panetta, J. H.; Parent, D.;
Pelassa, V.; Pesce-Rollins, M.; Pierbattista, M.; Piron, F.; Pivato,
G.; Porter, T. A.; Rainò, S.; Razzano, M.; Reimer, A.; Reimer,
O.; Roth, M.; Sadrozinski, H. F. -W.; Sgrò, C.; Siskind, E. J.;
Spandre, G.; Spinelli, P.; Strong, A. W.; Takahashi, H.; Takahashi,
T.; Tanaka, T.; Thayer, J. G.; Thayer, J. B.; Tibolla, O.; Tinivella,
M.; Torres, D. F.; Tramacere, A.; Troja, E.; Uchiyama, Y.; Usher,
T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vitale, V.;
Waite, A. P.; Wang, P.; Winer, B. L.; Wood, K. S.; Yang, Z.; Zimmer, S.
Bibcode: 2012ApJ...756....4A
Altcode: 2012arXiv1207.0616A
We report on the gamma-ray observations of giant molecular clouds
Orion A and B with the Large Area Telescope (LAT) on board the Fermi
Gamma-ray Space Telescope. The gamma-ray emission in the energy
band between ~100 MeV and ~100 GeV is predicted to trace the gas
mass distribution in the clouds through nuclear interactions between
the Galactic cosmic rays (CRs) and interstellar gas. The gamma-ray
production cross-section for the nuclear interaction is known to ~10%
precision which makes the LAT a powerful tool to measure the gas
mass column density distribution of molecular clouds for a known CR
intensity. We present here such distributions for Orion A and B, and
correlate them with those of the velocity-integrated CO intensity (W
CO) at a 1° × 1° pixel level. The correlation is found
to be linear over a W CO range of ~10-fold when divided
in three regions, suggesting penetration of nuclear CRs to most of
the cloud volumes. The W CO-to-mass conversion factor, X
CO, is found to be ~2.3 × 1020 cm-2(K
km s-1)-1 for the high-longitude part of Orion
A (l > 212°), ~1.7 times higher than ~1.3 × 1020
found for the rest of Orion A and B. We interpret the apparent high X
CO in the high-longitude region of Orion A in the light of
recent works proposing a nonlinear relation between H2 and
CO densities in the diffuse molecular gas. W CO decreases
faster than the H2 column density in the region making the
gas "darker" to W CO.
Title: Suppression of the near-infrared OH night-sky lines with
fibre Bragg gratings - first results
Authors: Ellis, S. C.; Bland-Hawthorn, J.; Lawrence, J.; Horton,
A. J.; Trinh, C.; Leon-Saval, S. G.; Shortridge, K.; Bryant, J.; Case,
S.; Colless, M.; Couch, W.; Freeman, K.; Gers, L.; Glazebrook, K.;
Haynes, R.; Lee, S.; Löhmannsröben, H. -G.; O'Byrne, J.; Miziarski,
S.; Roth, M.; Schmidt, B.; Tinney, C. G.; Zheng, J.
Bibcode: 2012MNRAS.425.1682E
Altcode: 2012MNRAS.tmp.3549E; 2012arXiv1206.6551E
The background noise between 1 and 1.8 μm in ground-based instruments
is dominated by atmospheric emission from hydroxyl molecules. We have
built and commissioned a new instrument, the Gemini Near-infrared OH
Suppression Integral Field Unit (IFU) System (GNOSIS), which suppresses
103 OH doublets between 1.47 and 1.7 μm by a factor of ≈1000
with a resolving power of ≈10 000. We present the first results
from the commissioning of GNOSIS using the IRIS2 spectrograph at the
Anglo-Australian Telescope. We present measurements of sensitivity,
background and throughput. The combined throughput of the GNOSIS
fore-optics, grating unit and relay optics is ≈36 per cent,
but this could be improved to ≈46 per cent with a more optimal
design. We measure strong suppression of the OH lines, confirming
that OH suppression with fibre Bragg gratings will be a powerful
technology for low-resolution spectroscopy. The integrated OH suppressed
background between 1.5 and 1.7 μm is reduced by a factor of 9 compared
to a control spectrum using the same system without suppression. The
potential of low-resolution OH-suppressed spectroscopy is illustrated
with example observations of Seyfert galaxies and a low-mass star. The GNOSIS background is dominated by detector dark current below
1.67 μm and by thermal emission above 1.67 μm. After subtracting
these, we detect an unidentified residual interline component of
≈860 ± 210 photons s-1 m-2 arcsec-2
μm-1, comparable to previous measurements. This component
is equally bright in the suppressed and control spectra. We have
investigated the possible source of the interline component, but
were unable to discriminate between a possible instrumental artefact
and intrinsic atmospheric emission. Resolving the source of this
emission is crucial for the design of fully optimized OH suppression
spectrographs. The next-generation OH suppression spectrograph
will be focused on resolving the source of the interline component,
taking advantage of better optimization for a fibre Bragg grating
feed incorporating refinements of design based on our findings from
GNOSIS. We quantify the necessary improvements for an optimal OH
suppressing fibre spectrograph design.
Title: GOCE orbit analysis: Long-wavelength gravity field
determination using the acceleration approach
Authors: Baur, O.; Reubelt, T.; Weigelt, M.; Roth, M.; Sneeuw, N.
Bibcode: 2012AdSpR..50..385B
Altcode:
The restricted sensitivity of the Gravity field and steady-state
Ocean Circulation Explorer (GOCE) gradiometer instrument requires
satellite gravity gradiometry to be supplemented by orbit analysis in
order to resolve long-wavelength features of the geopotential. For
the hitherto published releases of the GOCE time-wise (TIM)
and GOCE space-wise gravity field series—two of the official
ESA products—the energy conservation method has been adopted to
exploit GPS-based satellite-to-satellite tracking information. On
the other hand, gravity field recovery from data collected by the
CHAllenging Mini-satellite Payload (CHAMP) satellite showed the energy
conservation principle to be a sub-optimal choice. For this reason,
we propose to estimate the low-frequency part of the gravity field by
the point-wise solution of Newton's equation of motion, also known as
the acceleration approach. This approach balances the gravitational
vector with satellite accelerations, and hence is characterized by
(second-order) numerical differentiation of the kinematic orbit. In
order to apply the method to GOCE, we present tailored processing
strategies with regard to low-pass filtering, variance-covariance
information handling, and robust parameter estimation. By comparison
of our GIWF solutions (initials GI for "Geodätisches Institut" and IWF
for "Institut für WeltraumForschung") and the GOCE-TIM estimates with
a state-of-the-art gravity field solution derived from GRACE (Gravity
Recovery And Climate Experiment), we conclude that the acceleration
approach is better suited for GOCE-only gravity field determination
as opposed to the energy conservation method.
Title: Revealing the nature of magnetic shadows with numerical
3D-MHD simulations
Authors: Nutto, C.; Steiner, O.; Roth, M.
Bibcode: 2012A&A...542L..30N
Altcode: 2012arXiv1205.5308N
Aims: We investigate the interaction of magneto-acoustic waves
with magnetic network elements with the aim of finding possible
signatures of the magnetic shadow phenomenon in the vicinity of
network elements.
Methods: We carried out three-dimensional
numerical simulations of magneto-acoustic wave propagation in a model
solar atmosphere that is threaded by a complexly structured magnetic
field, resembling that of a typical magnetic network element and of
internetwork regions. High-frequency waves of 10 mHz are excited at
the bottom of the simulation domain. On their way through the upper
convection zone and through the photosphere and the chromosphere they
become perturbed, refracted, and converted into different mode types. We
applied a standard Fourier analysis to produce oscillatory power-maps
of the line-of-sight velocity.
Results: In the power maps of
the upper photosphere and the lower chromosphere, we clearly see the
magnetic shadow: a seam of suppressed power surrounding the magnetic
network elements. We demonstrate that this shadow is linked to the
mode conversion process and that power maps at these height levels
show the signature of three different magneto-acoustic wave modes.
Title: Anisotropy and dynamics of photospheric velocity patterns:
2D power and coherence analyses
Authors: Nesis, A.; Hammer, R.; Schleicher, H.; Roth, M.
Bibcode: 2012A&A...542A..85N
Altcode:
Context. The dynamical and topological properties of a fluid define its
hydrodynamical state and energy transfer. By means of two-dimensional
(2D) spectroscopy and 2D power and coherence analyses we study
these properties in the solar photosphere.
Aims: To obtain
insight into the change of the velocity field with height in the solar
photosphere we analyze 2D spectroscopic observations.
Methods:
Maps of the vertical velocity at four different photospheric heights
are studied by means of 2D power and coherence analyses, in order to
characterize the dynamical and topological properties of the velocity
field in the 2D wave number domain (kx,ky). (i)
The power analysis shows the power amplitude and its distribution
over the (kx,ky) domain for each velocity
map and thus height level. We use the mean azimuthal presentation
to provide a quick 1D overview. (ii) The cross-amplitude spectrum
shows interrelationships between two velocity maps. We use the
cross-amplitude spectrum to visualize and quantify changes of the
velocity patterns with height in the photosphere. (iii) The square
coherence is the normalized cross power spectrum; it represents the
correlation in the (kx,ky) domain. The degree of
isotropy of this quantity signifies the existence of velocity patterns
with different shapes. To facilitate the visualization of the 2D power
and coherence maps we calculate their 1D mean azimuthal values.
Results: The 2D power and coherence analyses reveal that the velocity
fields of the higher photospheric layers are different from the deeper
granular layers. The loss of similarity is found to occur in the mid
photosphere. The highest photospheric layers are characterized by (i)
a diminution of the velocity power; (ii) a disappearance of the small
velocity structures; and (iii) a tendency for larger upflow velocity
structures to become asymmetric.
Title: First Results from the SUNRISE Mission
Authors: Solanki, S. K.; Barthol, P.; Danilovic, S.; Feller, A.;
Gandorfer, A.; Hirzberger, J.; Jafarzadeh, S.; Lagg, A.; Riethmüller,
T. L.; Schüssler, M.; Wiegelmann, T.; Bonet, J. A.; González,
M. J. M.; Pillet, V. M.; Khomenko, E.; Yelles Chaouche, L.; Iniesta,
J. C. d. T.; Domingo, V.; Palacios, J.; Knölker, M.; González,
N. B.; Borrero, J. M.; Berkefeld, T.; Franz, M.; Roth, M.; Schmidt,
W.; Steiner, O.; Title, A. M.
Bibcode: 2012ASPC..455..143S
Altcode:
The SUNRISE balloon-borne solar observatory consists of a 1m aperture
Gregory telescope, a UV filter imager, an imaging vector polarimeter,
an image stabilization system, and further infrastructure. The first
science flight of SUNRISE yielded high-quality data that reveal the
structure, dynamics, and evolution of solar convection, oscillations,
and magnetic fields at a resolution of around 100 km in the quiet
Sun. Here we describe very briefly the mission and the first results
obtained from the SUNRISE data, which include a number of discoveries.
Title: Publisher's Note: Anisotropies in the diffuse gamma-ray
background measured by the Fermi LAT [Phys. Rev. D 85, 083007 (2012)]
Authors: Ackermann, M.; Ajello, M.; Albert, A.; Baldini, L.; Ballet,
J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.;
Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Brandt, T. J.; Bregeon,
J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro,
G. A.; Cameron, R. A.; Caraveo, P. A.; Cecchi, C.; Charles, E.;
Chekhtman, A.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi,
J.; Conrad, J.; Cuoco, A.; Cutini, S.; D'Ammando, F.; de Palma, F.;
Dermer, C. D.; Digel, S. W.; do Couto e Silva, E.; Drell, P. S.;
Drlica-Wagner, A.; Dubois, R.; Favuzzi, C.; Fegan, S. J.; Ferrara,
E. C.; Fortin, P.; Fukazawa, Y.; Fusco, P.; Gargano, F.; Gasparrini,
D.; Germani, S.; Giglietto, N.; Giroletti, M.; Glanzman, T.; Godfrey,
G.; Gomez-Vargas, G. A.; Grégoire, T.; Grenier, I. A.; Grove, J. E.;
Guiriec, S.; Gustafsson, M.; Hadasch, D.; Hayashida, M.; Hayashi, K.;
Hou, X.; Hughes, R. E.; Jóhannesson, G.; Johnson, A. S.; Kamae, T.;
Knödlseder, J.; Kuss, M.; Lande, J.; Latronico, L.; Lemoine-Goumard,
M.; Linden, T.; Lionetto, A. M.; Llena Garde, M.; Longo, F.; Loparco,
F.; Lovellette, M. N.; Lubrano, P.; Mazziotta, M. N.; McEnery, J. E.;
Mitthumsiri, W.; Mizuno, T.; Monte, C.; Monzani, M. E.; Morselli, A.;
Moskalenko, I. V.; Murgia, S.; Naumann-Godo, M.; Norris, J. P.; Nuss,
E.; Ohsugi, T.; Okumura, A.; Orienti, M.; Orlando, E.; Ormes, J. F.;
Paneque, D.; Panetta, J. H.; Parent, D.; Pavlidou, V.; Pesce-Rollins,
M.; Pierbattista, M.; Piron, F.; Pivato, G.; Rainò, S.; Rando, R.;
Reimer, A.; Reimer, O.; Roth, M.; Sbarra, C.; Schmitt, J.; Sgrò,
C.; Siegal-Gaskins, J.; Siskind, E. J.; Spandre, G.; Spinelli, P.;
Strong, A. W.; Suson, D. J.; Takahashi, H.; Tanaka, T.; Thayer,
J. B.; Tibaldo, L.; Tinivella, M.; Torres, D. F.; Tosti, G.; Troja,
E.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.;
Vitale, V.; Waite, A. P.; Winer, B. L.; Wood, K. S.; Wood, M.; Yang,
Z.; Zimmer, S.; Komatsu, E.
Bibcode: 2012PhRvD..85j9901A
Altcode:
No abstract at ADS
Title: A Uniform Asteroseismic Analysis of 22 Solar-type Stars
Observed by Kepler
Authors: Mathur, S.; Metcalfe, T. S.; Woitaszek, M.; Bruntt, H.;
Verner, G. A.; Christensen-Dalsgaard, J.; Creevey, O. L.; Doǧan, G.;
Basu, S.; Karoff, C.; Stello, D.; Appourchaux, T.; Campante, T. L.;
Chaplin, W. J.; García, R. A.; Bedding, T. R.; Benomar, O.; Bonanno,
A.; Deheuvels, S.; Elsworth, Y.; Gaulme, P.; Guzik, J. A.; Handberg,
R.; Hekker, S.; Herzberg, W.; Monteiro, M. J. P. F. G.; Piau, L.;
Quirion, P. -O.; Régulo, C.; Roth, M.; Salabert, D.; Serenelli, A.;
Thompson, M. J.; Trampedach, R.; White, T. R.; Ballot, J.; Brandão,
I. M.; Molenda-Żakowicz, J.; Kjeldsen, H.; Twicken, J. D.; Uddin,
K.; Wohler, B.
Bibcode: 2012ApJ...749..152M
Altcode: 2012arXiv1202.2844M
Asteroseismology with the Kepler space telescope is providing not
only an improved characterization of exoplanets and their host stars,
but also a new window on stellar structure and evolution for the
large sample of solar-type stars in the field. We perform a uniform
analysis of 22 of the brightest asteroseismic targets with the highest
signal-to-noise ratio observed for 1 month each during the first year
of the mission, and we quantify the precision and relative accuracy
of asteroseismic determinations of the stellar radius, mass, and age
that are possible using various methods. We present the properties
of each star in the sample derived from an automated analysis of the
individual oscillation frequencies and other observational constraints
using the Asteroseismic Modeling Portal (AMP), and we compare them to
the results of model-grid-based methods that fit the global oscillation
properties. We find that fitting the individual frequencies typically
yields asteroseismic radii and masses to ~1% precision, and ages to
~2.5% precision (respectively, 2, 5, and 8 times better than fitting
the global oscillation properties). The absolute level of agreement
between the results from different approaches is also encouraging,
with model-grid-based methods yielding slightly smaller estimates of
the radius and mass and slightly older values for the stellar age
relative to AMP, which computes a large number of dedicated models
for each star. The sample of targets for which this type of analysis
is possible will grow as longer data sets are obtained during the
remainder of the mission.
Title: The quasi-biennial periodicity (QBP) in velocity and intensity
helioseismic observations. The seismic QBP over solar cycle 23
Authors: Simoniello, R.; Finsterle, W.; Salabert, D.; García, R. A.;
Turck-Chièze, S.; Jiménez, A.; Roth, M.
Bibcode: 2012A&A...539A.135S
Altcode: 2012arXiv1201.2773S
Aims: We looked for signatures of quasi-biennial periodicity
(QBP) over different phases of solar cycle by means of acoustic modes
of oscillation. Low-degree p-mode frequencies are shown to be sensitive
to changes in magnetic activity due to the global dynamo. Recently
there has been reported evidence of two-year variations in p-mode
frequencies.
Methods: Long high-quality helioseismic data
are provided by BiSON (Birmingham Solar Oscillation Network), GONG
(Global Oscillation Network Group), GOLF (Global Oscillation at Low
Frequency) and VIRGO (Variability of Solar IRradiance and Gravity
Oscillation) instruments. We determined the solar cycle changes in
p-mode frequencies for spherical degree ℓ = 0, 1, 2 with their
azimuthal components in the frequency range 2.5 mHz ≤ ν ≤ 3.5
mHz.
Results: We found signatures of QBP at all levels of solar
activity in the modes more sensitive to higher latitudes. The signal
strength increases with latitude and the equatorial component also
seems to be modulated by the 11-year envelope.
Conclusions:
The persistent nature of the seismic QBP is not observed in the
surface activity indices, where mid-term variations are found only
from time to time and mainly in periods of high activity. This feature,
together with the latitudinal dependence, provides more evidence of a
mechanism that is almost independent and different from the one that
brings the active regions up to the surface. Therefore, these findings
can be used to provide more constraints on dynamo models that consider
a further cyclic component on top of the 11-year cycle.
Title: Modification of wave propagation and wave travel-time by the
presence of magnetic fields in the solar network atmosphere
Authors: Nutto, C.; Steiner, O.; Schaffenberger, W.; Roth, M.
Bibcode: 2012A&A...538A..79N
Altcode:
Context. Observations of waves at frequencies above the acoustic cut-off
frequency have revealed vanishing wave travel-times in the vicinity of
strong magnetic fields. This detection of apparently evanescent waves,
instead of the expected propagating waves, has remained a riddle.
Aims: We investigate the influence of a strong magnetic field on the
propagation of magneto-acoustic waves in the atmosphere of the solar
network. We test whether mode conversion effects can account for the
shortening in wave travel-times between different heights in the solar
atmosphere.
Methods: We carry out numerical simulations of the
complex magneto-atmosphere representing the solar magnetic network. In
the simulation domain, we artificially excite high frequency waves
whose wave travel-times between different height levels we then
analyze.
Results: The simulations demonstrate that the wave
travel-time in the solar magneto-atmosphere is strongly influenced by
mode conversion. In a layer enclosing the surface sheet defined by the
set of points where the Alfvén speed and the sound speed are equal,
called the equipartition level, energy is partially transferred from the
fast acoustic mode to the fast magnetic mode. Above the equipartition
level, the fast magnetic mode is refracted due to the large gradient
of the Alfvén speed. The refractive wave path and the increasing phase
speed of the fast mode inside the magnetic canopy significantly reduce
the wave travel-time, provided that both observing levels are above
the equipartition level.
Conclusions: Mode conversion and the
resulting excitation and propagation of fast magneto-acoustic waves is
responsible for the observation of vanishing wave travel-times in the
vicinity of strong magnetic fields. In particular, the wave propagation
behavior of the fast mode above the equipartition level may mimic
evanescent behavior. The present wave propagation experiments provide an
explanation of vanishing wave travel-times as observed with multi-line
high-cadence instruments. Movies are available in electronic form
at http://www.aanda.org
Title: Periodic Emission from the Gamma-Ray Binary 1FGL J1018.6-5856
Authors: Fermi LAT Collaboration; Ackermann, M.; Ajello, M.; Ballet,
J.; Barbiellini, G.; Bastieri, D.; Belfiore, A.; Bellazzini, R.;
Berenji, B.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland,
A. W.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson,
S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Cavazzuti,
E.; Cecchi, C.; Çelik, Ö.; Charles, E.; Chaty, S.; Chekhtman, A.;
Cheung, C. C.; Chiang, J.; Ciprini; , S.; Claus, R.; Cohen-Tanugi, J.;
Corbel, S.; Corbet, R. H. D.; Cutini, S.; de Luca, A.; den Hartog,
P. R.; de Palma, F.; Dermer, C. D.; Digel, S. W.; do Couto e Silva,
E.; Donato, D.; Drell, P. S.; Drlica-Wagner, A.; Dubois, R.; Dubus,
G.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Focke, W. B.; Fortin,
P.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.;
Gehrels, N.; Germani, S.; Giglietto, N.; Giordano, F.; Giroletti, M.;
Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grove, J. E.; Guiriec, S.;
Hadasch, D.; Hanabata, Y.; Harding, A. K.; Hayashida, M.; Hays, E.;
Hill, A. B.; Hughes, R. E.; Jóhannesson, G.; Johnson, A. S.; Johnson,
T. J.; Kamae, T.; Katagiri, H.; Kataoka, J.; Kerr, M.; Knödlseder,
J.; Kuss, M.; Lande, J.; Longo, F.; Loparco, F.; Lovellette, M. N.;
Lubrano, P.; Mazziotta, M. N.; McEnery, J. E.; Michelson, P. F.;
Mitthumsiri, W.; Mizuno, T.; Monte, C.; Monzani, M. E.; Morselli,
A.; Moskalenko, I. V.; Murgia, S.; Nakamori, T.; Naumann-Godo, M.;
Norris, J. P.; Nuss, E.; Ohno, M.; Ohsugi, T.; Okumura, A.; Omodei,
N.; Orlando, E.; Ozaki, M.; Paneque, D.; Parent, D.; Pesce-Rollins,
M.; Pierbattista, M.; Piron, F.; Pivato, G.; Porter, T. A.; Rainò,
S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Ritz, S.; Romani,
R. W.; Roth, M.; Saz Parkinson, P. M.; Sgrò, C.; Siskind, E. J.;
Spandre, G.; Spinelli, P.; Suson, D. J.; Takahashi, H.; Tanaka, T.;
Thayer, J. G.; Thayer, J. B.; Thompson, D. J.; Tibaldo, L.; Tinivella,
M.; Torres, D. F.; Tosti, G.; Troja, E.; Uchiyama, Y.; Usher, T. L.;
Vandenbroucke, J.; Vianello, G.; Vitale, V.; Waite, A. P.; Winer,
B. L.; Wood, K. S.; Wood, M.; Yang, Z.; Zimmer, S.; Coe, M. J.; Di
Mille, F.; Edwards, P. G.; Filipović, M. D.; Payne, J. L.; Stevens,
J.; Torres, M. A. P.
Bibcode: 2012Sci...335..189F
Altcode: 2012Sci...335..189A; 2012arXiv1202.3164T
Gamma-ray binaries are stellar systems containing a neutron star or
black hole, with gamma-ray emission produced by an interaction between
the components. These systems are rare, even though binary evolution
models predict dozens in our Galaxy. A search for gamma-ray binaries
with the Fermi Large Area Telescope (LAT) shows that 1FGL J1018.6-5856
exhibits intensity and spectral modulation with a 16.6-day period. We
identified a variable x-ray counterpart, which shows a sharp maximum
coinciding with maximum gamma-ray emission, as well as an O6V((f)) star
optical counterpart and a radio counterpart that is also apparently
modulated on the orbital period. 1FGL J1018.6-5856 is thus a gamma-ray
binary, and its detection suggests the presence of other fainter
binaries in the Galaxy.
Title: HETDEX: Overview of the Hobby-Eberly Telescope Dark Energy
Experiment and Instrumentation
Authors: Hill, Gary J.; Gebhardt, K.; Drory, N.; DePoy, D.; Komatsu,
E.; Bender, R.; Schneider, D.; Fabricius, M.; Lee, H.; Tuttle, S.;
Marshall, J.; Kelz, A.; Roth, M.; Cornell, M.; HETDEX Collaboration
Bibcode: 2012AAS...21942401H
Altcode:
The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) is a
blind spectroscopic survey to map the evolution of dark energy using
Lyman-alpha emitting galaxies as tracers. HETDEX comprises a major
upgrade of the HET, deployment of the massively replicated integral
field spectrograph, VIRUS, and the execution of a multi-year blind
spectroscopic survey. VIRUS, consists of 75 IFUs distributed across the
22-arcmin field of the upgraded 9.2-m HET. Each 50x50 sq. arcsec IFU
is made up of 448 1.5-arcsec fibers, and feeds a pair of spectrographs
with a fixed bandpass of 350-550 nm and resolving power R 700. Each
exposure gathers 33,600 spectra. Observing 20 minutes per field, we
reach a line flux limit of 3.5e-17 ergs-sec-1-cm-2 and mAB 22. The
baseline survey will deliver spectra of 0.8M LAEs in a 9 cubic Gpc
volume with 1.9 < z < 3.5, and 1M [OII] emitters with z <
0.48. In addition, the survey will cover 0.4M other galaxies, 0.25M
stars, 2000 galaxy clusters, 7000 QSOs with z < 3.5, and 20,000
NVSS radio sources. The main survey area of 42x7 sq. deg. is centered
at 13hr, +53deg. Within that 300 sq. deg. region we cover 1/4.5 with
fibers; thus 60 sq. deg. of sky have spectra. Initial observations
will be conducted from Spring 2013 through Spring 2015. We present an
overview of the project, including instrumentation and details of the
planned surveys.
Title: Propiedades infrarrojas de regiones de formación estelar
Title: Propiedades infrarrojas de regiones de formación estelar
Title: Infrared properties of star-forming regions.
Authors: Saldaño, H. P.; Persi, P.; Tapia, M.; Roth, M.; Gómez, M.
Bibcode: 2012stas.conf...99S
Altcode:
We present an analysis of near-IR images, obtained with the instrument
PANIC at the Baade telescope (Las Campanas), of the star-forming regions
associated with the sources IRAS 12272-6240 and IRAS 17149-3916,
selected from the southern sky survey of sub-mm cores of Beltran
et al. (2006). We identify two young clusters associated with each
one of the IRAS sources. The near-IR color-color and color-magnitude
diagrams are used to detect young stars with masses between 0.7 and 30
solar masses. We find approximately 190 and 285 sources in the IRAS
12272-6240 and IRAS 17149-3916 regions, showing near-IR excesses due
to circumstellar material and that probably belong to the identified
young clusters.
Title: Fermi Detection of a Luminous γ-Ray Pulsar in a Globular
Cluster
Authors: Freire, P. C. C.; Abdo, A. A.; Ajello, M.; Allafort, A.;
Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini,
R.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.;
Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G.;
Cameron, R.; Camilo, F.; Caraveo, P. A.; Cecchi, C.; Çelik, Ö.;
Charles, E.; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Ciprini, S.;
Claus, R.; Cognard, I.; Cohen-Tanugi, J.; Cominsky, L. R.; de Palma,
F.; Dermer, C. D.; do Couto e Silva, E.; Dormody, M.; Drell, P. S.;
Dubois, R.; Dumora, D.; Espinoza, C. M.; Favuzzi, C.; Fegan, S. J.;
Ferrara, E. C.; Focke, W. B.; Fortin, P.; Fukazawa, Y.; Fusco, P.;
Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giglietto,
N.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier,
I. A.; Grondin, M. -H.; Grove, J. E.; Guillemot, L.; Guiriec, S.;
Hadasch, D.; Harding, A. K.; Jóhannesson, G.; Johnson, A. S.; Johnson,
T. J.; Johnston, S.; Katagiri, H.; Kataoka, J.; Keith, M.; Kerr, M.;
Knödlseder, J.; Kramer, M.; Kuss, M.; Lande, J.; Latronico, L.; Lee,
S. -H.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lovellette, M. N.;
Lubrano, P.; Lyne, A. G.; Manchester, R. N.; Marelli, M.; Mazziotta,
M. N.; McEnery, J. E.; Michelson, P. F.; Mizuno, T.; Moiseev, A. A.;
Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia,
S.; Nakamori, T.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohsugi,
T.; Okumura, A.; Omodei, N.; Orlando, E.; Ozaki, M.; Paneque, D.;
Parent, D.; Pesce-Rollins, M.; Pierbattista, M.; Piron, F.; Porter,
T. A.; Rainò, S.; Ransom, S. M.; Ray, P. S.; Reimer, A.; Reimer,
O.; Reposeur, T.; Ritz, S.; Romani, R. W.; Roth, M.; Sadrozinski,
H. F. -W.; Saz Parkinson, P. M. Sgrò, C.; Shannon, R.; Siskind,
E. J. Smith, D. A.; Smith, P. D.; Spinelli, P.; Stappers, B. W.;
Suson, D. J.; Takahashi, H.; Tanaka, T.; Tauris, T. M.; Thayer,
J. B.; Theureau, G.; Thompson, D. J.; Thorsett, S. E.; Tibaldo, L.;
Torres, D. F.; Tosti, G.; Troja, E.; Vandenbroucke, J.; Van Etten,
A.; Vasileiou, V.; Venter, C.; Vianello, G.; Vilchez, N.; Vitale, V.;
Waite, A. P.; Wang, P.; Wood, K. S.; Yang, Z.; Ziegler, M.; Zimmer, S.
Bibcode: 2011Sci...334.1107F
Altcode: 2011Sci...334.1107.; 2011arXiv1111.3754T
We report on the Fermi Large Area Telescope’s detection of γ-ray
(>100 mega-electron volts) pulsations from pulsar J1823-3021A in
the globular cluster NGC 6624 with high significance (∼7 σ). Its
γ-ray luminosity, Lγ = (8.4 ± 1.6) × 1034
ergs per second, is the highest observed for any millisecond pulsar
(MSP) to date, and it accounts for most of the cluster emission. The
nondetection of the cluster in the off-pulse phase implies that it
contains <32 γ-ray MSPs, not ∼100 as previously estimated. The
γ-ray luminosity indicates that the unusually large rate of change
of its period is caused by its intrinsic spin-down. This implies that
J1823-3021A has the largest magnetic field and is the youngest MSP
ever detected and that such anomalous objects might be forming at
rates comparable to those of the more normal MSPs.
Title: The Kepler characterization of the variability among A-
and F-type stars. I. General overview
Authors: Uytterhoeven, K.; Moya, A.; Grigahcène, A.; Guzik,
J. A.; Gutiérrez-Soto, J.; Smalley, B.; Handler, G.; Balona,
L. A.; Niemczura, E.; Fox Machado, L.; Benatti, S.; Chapellier, E.;
Tkachenko, A.; Szabó, R.; Suárez, J. C.; Ripepi, V.; Pascual, J.;
Mathias, P.; Martín-Ruíz, S.; Lehmann, H.; Jackiewicz, J.; Hekker,
S.; Gruberbauer, M.; García, R. A.; Dumusque, X.; Díaz-Fraile, D.;
Bradley, P.; Antoci, V.; Roth, M.; Leroy, B.; Murphy, S. J.; De Cat,
P.; Cuypers, J.; Kjeldsen, H.; Christensen-Dalsgaard, J.; Breger, M.;
Pigulski, A.; Kiss, L. L.; Still, M.; Thompson, S. E.; van Cleve, J.
Bibcode: 2011A&A...534A.125U
Altcode: 2011arXiv1107.0335U
Context. The Kepler spacecraft is providing time series of photometric
data with micromagnitude precision for hundreds of A-F type stars.
Aims: We present a first general characterization of the pulsational
behaviour of A-F type stars as observed in the Kepler light curves
of a sample of 750 candidate A-F type stars, and observationally
investigate the relation between γ Doradus (γ Dor), δ Scuti
(δ Sct), and hybrid stars.
Methods: We compile a database
of physical parameters for the sample stars from the literature and
new ground-based observations. We analyse the Kepler light curve of
each star and extract the pulsational frequencies using different
frequency analysis methods. We construct two new observables, "energy"
and "efficiency", related to the driving energy of the pulsation
mode and the convective efficiency of the outer convective zone,
respectively.
Results: We propose three main groups to describe
the observed variety in pulsating A-F type stars: γ Dor, δ Sct, and
hybrid stars. We assign 63% of our sample to one of the three groups,
and identify the remaining part as rotationally modulated/active stars,
binaries, stars of different spectral type, or stars that show no clear
periodic variability. 23% of the stars (171 stars) are hybrid stars,
which is a much higher fraction than what has been observed before. We
characterize for the first time a large number of A-F type stars (475
stars) in terms of number of detected frequencies, frequency range,
and typical pulsation amplitudes. The majority of hybrid stars show
frequencies with all kinds of periodicities within the γ Dor and δ
Sct range, also between 5 and 10 d-1, which is a challenge
for the current models. We find indications for the existence of δ
Sct and γ Dor stars beyond the edges of the current observational
instability strips. The hybrid stars occupy the entire region within
the δ Sct and γ Dor instability strips and beyond. Non-variable
stars seem to exist within the instability strips. The location of
γ Dor and δ Sct classes in the (Teff, log g)-diagram
has been extended. We investigate two newly constructed variables,
"efficiency" and "energy", as a means to explore the relation between
γ Dor and δ Sct stars.
Conclusions: Our results suggest a
revision of the current observational instability strips of δ Sct and
γ Dor stars and imply an investigation of pulsation mechanisms to
supplement the κ mechanism and convective blocking effect to drive
hybrid pulsations. Accurate physical parameters for all stars are
needed to confirm these findings.
Title: Embedded young stars in northern NGC 3372
Authors: Tapia, M.; Roth, M.; Persi, P.
Bibcode: 2011RMxAC..40..255T
Altcode:
Deep narrow-band (Brγ at 2.17μm and H_2 at 2.12μm) and broad-band
(JHKs) near-infrared images are presented of the young regions Tr14-N4
and Car I. The observations were made with PANIC, attached to the
Baade 6.5 m Magellan Telescope at Las Campanas Observatory. These were
supplemented by archive Spitzer/IRAC images. Evidence is given of an
embedded young compact cluster (r=23'') of medium-to-low mass stars
in Tr14-N4 but that includes at least one high mass protostar. Its
properties are derived from the 1.2 to 11μm photometry. The presence of
outflows is evinced by knotty H_2 emission near the edge of a cavity. We
also presented updates of near-IR light-curves of Car I-136 and 125
embedded in the dark cloud associated with Car I.
Title: Recent results from helioseismic measurements of the meridional
flow using the Fourier-Legendre decomposition technique
Authors: Glogowski, Kolja; Doerr, Hans-Peter; Roth, Markus
Bibcode: 2011sdmi.confE..56G
Altcode:
We use the Fourier-Legendre decomposition (FLD) technique to measure
the sub-surface meridional flow and present recent results obtained
with data from the GONG and HMI instruments. The FLD technique was
originally developed by Braun et al. (1988) to study p-mode absorption
in sunspots and applied by Braun & Fan (1998) to measure the
meridional flow. The time-dependent oscillation signal is decomposed
into pole- and equatorward traveling wave fields whose power spectra
show a slight frequency shift that is related to the meridional flow
in sub-surface layers of the convection zone. We applied the FLD
to time series of Doppler velocity maps provided by the GONG and HMI
instruments and used the SOLA inversion method (Pijpers & Thompson,
1994) to derive the velocity of the sub-surface meridional flow from the
measured frequency shifts and the solar model S of Christensen-Dalsgaard
et al. (1996). By averaging over large parts of each solar hemisphere
we were able to measure the meridional flow down to a depth of 60 Mm,
while smaller patches at different latitudes allowed us to analyze
its latitudinal variation at lower depths.
Title: The future of helioseismology
Authors: Roth, M.
Bibcode: 2011CoSka..41..156R
Altcode:
Helioseismology is the only possibility to probe the conditions inside
the Sun, which advances our understanding of the solar structure and
the Sun's influence on the Earth. The field of helioseismology has
been developing rapidly since the 1980s thanks to dedicated projects
like the Solar and Heliospheric Observatory (SOHO) and the Global
Oscillation Network Group (GONG). The field is now about to take a
giant leap forward with the successful launches of the Solar Dynamics
Observatory (SDO) and the PICARD mission with vastly better spatial
and temporal resolution. This now allows to make use of the full
potential of local and global helioseismology techniques to study
inhomogeneities in the solar interior which are connected to solar
dynamo action. In addition, new ground-based instruments are being
developed for complementing in unique ways the space observations by
establishing physical relationships between internal solar properties
and magnetic activity in the solar atmosphere. This paper summarizes
the new goals, possibilities, and prospects of helioseismology.
Title: Outburst near-infrared and Chandra observations of the
ms-pulsar IGR J17498-2921
Authors: Torres, M. A. P.; Madej, O.; Jonker, P. G.; Steeghs, D.;
Greiss, S.; Morrell, N.; Roth, M.
Bibcode: 2011ATel.3638....1T
Altcode:
We report on near-infrared and Chandra follow-up observations of the
currently active accreting ms-pulsar IGR J17498-2921 (ATel #3551,
#3556). An H-band infrared counterpart candidate with H= 15.7 ± 0.1
mag has been suggested in ATel #3562 on the basis of its coincidence
with the Chandra position for the X-ray source (ATel #3559, #3606;
cf. ATel #3634). INFRARED PHOTOMETRY: We have acquired a series of
45s H-band images on 2011 Sep 02 03:13 - 03:41 UT using the Retrocam
camera attached to the 2.5m Irenee du Pont telescope at Las Campanas
observatory.
Title: The Sun at high resolution: first results from the Sunrise
mission
Authors: Solanki, S. K.; Barthol, P.; Danilovic, S.; Feller,
A.; Gandorfer, A.; Hirzberger, J.; Lagg, A.; Riethmüller, T. L.;
Schüssler, M.; Wiegelmann, T.; Bonet, J. A.; Pillet, V. Martínez;
Khomenko, E.; del Toro Iniesta, J. C.; Domingo, V.; Palacios, J.;
Knölker, M.; González, N. Bello; Borrero, J. M.; Berkefeld, T.;
Franz, M.; Roth, M.; Schmidt, W.; Steiner, O.; Title, A. M.
Bibcode: 2011IAUS..273..226S
Altcode:
The Sunrise balloon-borne solar observatory consists of a 1m aperture
Gregory telescope, a UV filter imager, an imaging vector polarimeter,
an image stabilization system and further infrastructure. The first
science flight of Sunrise yielded high-quality data that reveal the
structure, dynamics and evolution of solar convection, oscillations
and magnetic fields at a resolution of around 100 km in the quiet
Sun. Here we describe very briefly the mission and the first results
obtained from the Sunrise data, which include a number of discoveries.
Title: Long Wavelength Gravity Field Determination from GOCE Using
the Acceleration Approach
Authors: Weigelt, M.; Baur, O.; Reubelt, T.; Sneeuw, N.; Roth, M.
Bibcode: 2011ESASP.696E..36W
Altcode:
In the GOCE (Gravity field and steady-state Ocean Circulation Explorer)
mission two types of techniques are used for the recovery of the
gravity field: gradiometry for the medium to short wavelengths and
high-low satellite- to-satellite tracking (hl-SST) for the long
wavelength features. For the latter, it is necessary to make use
of GPS observations due to the limited measurement bandwidth of the
gradiometer. In this contribution we focus on this part. Currently,
the processing facilities derive the long- wavelength features by using
the energy conservation ap proach. We propose to use the acceleration
approach, instead, as earlier studies for CHAMP showed that it offers a
superior alternative. Theory suggest that the solution can be improved
since gravity field information is available in all three directions
whereas in case of the energy balance the information is primarily
alongtrack. We show that for the low degrees such an improvement can
be achieved. However, the processing is still at an early stage and
further improvements are expected using improved filtering, better
outlier detection and more reliable error information. The procedure
aims at the optimal recovery of a GOCE-only solution which is one of
the key objectives within the ESA's Living Planet Programme.
Title: A Unified Approach to the Helioseismic Inversion Problem of
the Solar Meridional Flow from Global Oscillations
Authors: Schad, A.; Timmer, J.; Roth, M.
Bibcode: 2011ApJ...734...97S
Altcode:
Measurements from tracers and local helioseismology indicate the
existence of a meridional flow in the Sun with strength in the order
of 15 m s-1 near the solar surface. Different attempts were
made to obtain information on the flow profile at depths up to 20 Mm
below the solar surface. We propose a method using global helioseismic
Doppler measurements with the prospect of inferring the meridional flow
profile at greater depths. Our approach is based on the perturbation
of the p-mode eigenfunctions of a solar model due to the presence of a
flow. The distortion of the oscillation eigenfunctions is manifested
in the mixing of p-modes, which may be measured from global solar
oscillation time series. As a new helioseismic measurement quantity,
we propose amplitude ratios between oscillations in the Fourier
domain. We relate this quantity to the meridional flow and unify
the concepts presented here for an inversion procedure to infer the
meridional flow from global solar oscillations.
Title: Helioseismic Measurements Of Meridional Flows In Artificial
Data From 3d Numerical Simulations Of Wave Propagation In The
Whole Sun
Authors: Hartlep, Thomas; Roth, M.; Doerr, H.; Zhao, J.; Kosovichev,
A. G.
Bibcode: 2011SPD....42.1611H
Altcode: 2011BAAS..43S.1611H
Measuring the structure of the deep solar interior is of considerable
interest for understanding how the solar dynamo functions. In
particular, the structure of the meridional flow and the depth of
its return flow are of significant interest. Detecting such small
flows in the deep interior is a challenging problem. Numerical
simulations can provide means for testing and calibrating measurement
techniques and help increase our confidence in the inferences obtained
from observations. We present results from analyzing artificial
helioseismology data obtained from numerical simulations of helioseismic
wave propagation in the whole 3D solar interior with models of the
meridional circulation present in the background state. Two methods
- a time-distance helioseismology technique and a Fourier-Legendre
decomposition technique - are used in this paper to try to detect and
measure this flow from the oscillations at the solar surface.
Title: Excitation of Stellar Oscillations by Gravitational Waves:
Hydrodynamic Model and Numerical Results for the Sun
Authors: Siegel, D. M.; Roth, M.
Bibcode: 2011ApJ...729..137S
Altcode: 2011arXiv1103.0373S
Starting from a general relativistic framework, a hydrodynamic
formalism is derived that yields the mean-square amplitudes and rms
surface velocities of normal modes of non-relativistic stars excited by
arbitrary gravitational wave (GW) radiation. In particular, stationary
GW fields are considered and the resulting formulae are evaluated
for two general types of GW radiation: radiation from a particular
astrophysical source (e.g., a binary system) and a stochastic background
of gravitational waves (SBGW). Expected sources and signal strengths
for both types of GW radiation are reviewed and discussed. Numerical
results for the Sun show that low-order quadrupolar g modes are
excited more strongly than p modes by orders of magnitude. Maximal
rms surface velocities in the case of excitation by astrophysical
sources are found to be v <~ 10-8 mm s-1,
assuming GW strain amplitudes of h <~ 10-20. It is
shown that current models for an SBGW produced by cosmic strings, with
ΩGW ~ 10-8-10-5 in the frequency range
of solar g modes, are able to produce maximal solar g-mode rms surface
velocities of 10-5-10-3 mm s-1. This
result lies close or within the amplitude range of 10-3-1
mm s-1 expected from excitation by turbulent convection,
which is currently considered to be responsible for stellar g-mode
excitation. It is concluded that studying g-mode observations of stars
other than the Sun, in which excitation by GWs could be even more
effective due to different stellar structures, might provide a new
method to either detect GWs or to deduce a significant direct upper
limit on an SBGW at intermediate frequencies between the pulsar bound
and the bounds from interferometric detectors on Earth.
Title: Wave absorption and moat flow in AR9787
Authors: Roth, M.; Thompson, M. J.
Bibcode: 2011JPhCS.271a2022R
Altcode:
We present the results of a study of the wave absorption and the moat
flow around the sunspot in AR9787 (the "HELAS sunspot", so-called
because it has been the object of in-depth study at a HELAS workshop)
using Fourier-Hankel decomposition of the oscillatory wave field. We
carry out inversions both for the flow speed and for the sound speed
perturbation as a function of depth. The results are compared with
results from time-distance helioseismology.
Title: Observation of oscillation coupling ratios and the meridional
flow
Authors: Schad, A.; Roth, M.; Timmer, J.
Bibcode: 2011JPhCS.271a2079S
Altcode:
Measurements from local helioseismology indicate the existence of
a meridional flow in the Sun with a strength up to 15 m/s near the
solar surface. The flow profile at depths below approx 15 Mm are not
accessible. We propose a method using global helioseismic measurements
with the prospect to infer the meridional flow profile throughout the
solar convection zone and show its performance on simulated data.
Title: Localized averaging kernels for probing the deep meridional
flow with data from GONG, MDI and HMI
Authors: Doerr, H. -P.; Roth, M.
Bibcode: 2011JPhCS.271a2057D
Altcode:
The Fourier-Legendre decomposition (FLD) method to study wave absorption
in sunspots is a helioseismic technique which is also suited for
the measurement of the meridional flow. Because the FLD method is
sensible to low-degree oscillation modes, it bears the potential to
be used to probe the average meridional flow in much deeper layers
as it is currently possible with other methods. In order to rate the
suitability of the available data for inversions of the deep flow,
we compare localized averaging kernels as computed with data from the
Global Oscillation Network Group (GONG), the Michelson Doppler Imager
(MDI) aboard the SOHO spacecraft and also with preliminary data from
the Helioseismic and Magnetic Imager (HMI) aboard the SDO spacecraft.
Title: Kepler observations: Light shed on the hybrid γ Doradus -
δ Scuti pulsation phenomenon
Authors: Grigahcène, A.; Uytterhoeven, K.; Antoci, V.; Balona, L.;
Catanzaro, G.; Daszyńska-Daszkiewicz, J.; Guzik, J. A.; Handler, G.;
Houdek, G.; Kurtz, D. W.; Marconi, M.; Monteiro, M. J. P. F. G.;
Moya, A.; Ripepi, V.; Suárez, J. -C.; Borucki, W. J.; Brown,
T. M.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Jenkins, J. M.;
Kjeldsen, H.; Koch, D.; Bernabei, S.; Bradley, P.; Breger, M.; Di
Criscienzo, M.; Dupret, M. -A.; García, R. A.; García Hernández, A.;
Jackiewicz, J.; Kaiser, A.; Lehmann, H.; Martín-Ruiz, S.; Mathias,
P.; Molenda-Żakowicz, J.; Nemec, J. M.; Nuspl, J.; Paparó, M.;
Roth, M.; Szabó, R.; Suran, M. D.; Ventura, R.
Bibcode: 2010AN....331..989G
Altcode:
Through the observational study of stellar pulsations, the internal
structure of stars can be probed and theoretical models can be
tested. The main sequence γ Doradus (Dor) and δ Scuti (Sct) stars
with masses 1.2-2.5 M⊙ are particularly interesting for
asteroseismic study. The γ Dor stars pulsate in high-order gravity (g)
modes, with pulsational periods of order of one day. The δ Sct stars,
on the other hand, show low-order g and pressure (p) modes with periods
of order of 2 hours. Theory predicts the existence of `hybrid' stars,
i.e. stars pulsating in both types of modes, in an overlap region
between the instability strips of γ Dor and δ Sct stars in the
Hertzsprung-Russell diagram. Hybrid stars are particularly interesting
as the two types of modes probe different regions of the stellar
interior and hence provide complementary model constraints. Before
the advent of Kepler, only a few hybrid stars had been confirmed. The
{{Kepler}} satellite is providing a true revolution in the study
of and search for hybrid stars. Analysis of the first 50 days of
{{Kepler}} data of hundreds of γ Dor and δ Sct candidates reveals
extremely rich frequency spectra, with most stars showing frequencies
in both the δ Sct and γ Dor frequency range. As these results show
that there are practically no pure δ Sct or γ Dor pulsators, a new
observational classification scheme is proposed by \cite{Grig10}. We
present their results and characterize 234 stars in terms of δ Sct,
γ Dor, δ Sct/γ Dor or γ Dor/δ Sct hybrids.
Title: Meridional flow: Perturbed mode frequencies and eigenfunctions
Authors: Roth, M.
Bibcode: 2010AN....331..907R
Altcode:
Two models for components of the meridional circulation in the Sun
obeying the continuity equation are used for studying the effect of
these large-scale flow models on solar {p}-modes. The models adapt
major properties of meridional circulation cells in simulations of
global solar convection. The perturbation effect of these models
on the solar eigenstates and eigenfrequencies is determined by
quasi-degenerate perturbation theory. The general finding is that
determining the frequency multiplets of the solar {p}-modes, the two
meridional circulation models lead on average to negative frequency
shifts of the multiplets. The relative mean frequency shift \delta \nu /
\nu is less than 2 × 10-5. Investigating the eigenfunction,
the perturbation is in the order of 10-4.
Title: A new code for Fourier-Legendre analysis of large datasets:
First results and a comparison with ring-diagram analysis
Authors: Doerr, H. -P.; Roth, M.; Zaatri, A.; Krieger, L.; Thompson,
M. J.
Bibcode: 2010AN....331..911D
Altcode: 2010arXiv1011.4152D
Fourier-Legendre decomposition (FLD) of solar Doppler imaging data is a
promising method to estimate the sub-surface solar meridional flow. FLD
is sensible to low-degree oscillation modes and thus has the potential
to probe the deep meridional flow. We present a newly developed code to
be used for large scale FLD analysis of helioseismic data as provided
by the Global Oscillation Network Group (GONG), the Michelson Doppler
Imager (MDI) instrument, and the upcoming Helioseismic and Magnetic
Imager (HMI) instrument. First results obtained with the new code are
qualitatively comparable to those obtained from ring-diagram analyis
of the same time series.
Title: Asteroseismology of solar-type stars with Kepler I: Data
analysis
Authors: Karoff, C.; Chaplin, W. J.; Appourchaux, T.; Elsworth, Y.;
Garcia, R. A.; Houdek, G.; Metcalfe, T. S.; Molenda-Żakowicz, J.;
Monteiro, M. J. P. F. G.; Thompson, M. J.; Christensen-Dalsgaard, J.;
Gilliland, R. L.; Kjeldsen, H.; Basu, S.; Bedding, T. R.; Campante,
T. L.; Eggenberger, P.; Fletcher, S. T.; Gaulme, P.; Handberg, R.;
Hekker, S.; Martic, M.; Mathur, S.; Mosser, B.; Regulo, C.; Roxburgh,
I. W.; Salabert, D.; Stello, D.; Verner, G. A.; Belkacem, K.; Biazzo,
K.; Cunha, M. S.; Gruberbauer, M.; Guzik, J. A.; Kupka, F.; Leroy,
B.; Ludwig, H. -G.; Mathis, S.; Noels, A.; Noyes, R. W.; Roca Cortes,
T.; Roth, M.; Sato, K. H.; Schmitt, J.; Suran, M. D.; Trampedach,
R.; Uytterhoeven, K.; Ventura, R.
Bibcode: 2010AN....331..972K
Altcode: 2010arXiv1005.0507K
We report on the first asteroseismic analysis of solar-type stars
observed by Kepler. Observations of three G-type stars, made at
one-minute cadence during the first 33.5 days of science operations,
reveal high signal-to-noise solar-like oscillation spectra in all three
stars: About 20 modes of oscillation can clearly be distinguished
in each star. We discuss the appearance of the oscillation spectra,
including the presence of a possible signature of faculae, and the
presence of mixed modes in one of the three stars.
Title: Four years of HELAS
Authors: Roth, M.; Lühe, O. v. d.; Aerts, C.; Christensen-Dalsgaard,
J.; Corbard, T.; Daszyńska-Daszkiewicz, J.; Di Mauro, M. P.; Gizon,
L.; Jiménez-Reyes, S.; Monteiro, M. J. P. F. G.; Pallé, P. L.;
Thompson, M. J.
Bibcode: 2010AN....331.1084R
Altcode:
The European Coordination Action on HELio- and ASteroseismology
(HELAS) has completed its fourth and final year of initial funding by
the European Commission. Set up as a network which combines solar and
stellar physics communities in the important and vigorously evolving
field of seismology, HELAS has been able to coordinate the efforts of
European astronomers with remarkable success. Four large international
conferences including the HELAS-IV conference on Lanzarote as well as
many workshops were organized with a substantial contribution from
HELAS. About a dozen workshops, addressing specialized questions in
global and local helioseismology and asteroseismology were entirely
organized by HELAS. Data analysis tools to prepare the European
communities for the upcoming influx of data from new missions have
been prepared, tested and demonstrated. Lecture notes and outreach
material have been assembled and prepared for general access. As a
result, HELAS has an important impact on the scientific output of the
astrophysics seismology communities and significantly increased the
visibility of European research in this field. This paper summarizes
the activities and accomplishments of HELAS.
Title: Magneto-acoustic wave propagation and mode conversion
in a magnetic solar atmosphere: Comparing results from the
CO5BOLD code with ray theory
Authors: Nutto, C.; Steiner, O.; Roth, M.
Bibcode: 2010AN....331..915N
Altcode: 2010arXiv1009.5586N
We present simulations of magneto-acoustic wave propagation in
a magnetic, plane-parallel stratified solar model atmosphere,
employing the CO5BOLD-code. The tests are carried out for
two models of the solar atmosphere, which are similar to the ones used
by \citet{nutto_cally07} and \citet{nutto_schunker06}. The two models
differ only in the orientation of the magnetic field. A qualitative
comparison shows good agreement between the numerical results and the
results from ray theory. The tests are done in view of the application
of the present numerical code for the computation of energy fluxes
of propagating acoustic waves into a dynamically evolving magnetic
solar atmosphere. For this, we consider waves with frequencies above
the acoustic cut-off frequency.
Title: Modeling the Subsurface Structure of Sunspots
Authors: Moradi, H.; Baldner, C.; Birch, A. C.; Braun, D. C.; Cameron,
R. H.; Duvall, T. L.; Gizon, L.; Haber, D.; Hanasoge, S. M.; Hindman,
B. W.; Jackiewicz, J.; Khomenko, E.; Komm, R.; Rajaguru, P.; Rempel,
M.; Roth, M.; Schlichenmaier, R.; Schunker, H.; Spruit, H. C.;
Strassmeier, K. G.; Thompson, M. J.; Zharkov, S.
Bibcode: 2010SoPh..267....1M
Altcode: 2009arXiv0912.4982M; 2010SoPh..tmp..171M
While sunspots are easily observed at the solar surface, determining
their subsurface structure is not trivial. There are two main
hypotheses for the subsurface structure of sunspots: the monolithic
model and the cluster model. Local helioseismology is the only means
by which we can investigate subphotospheric structure. However, as
current linear inversion techniques do not yet allow helioseismology to
probe the internal structure with sufficient confidence to distinguish
between the monolith and cluster models, the development of physically
realistic sunspot models are a priority for helioseismologists. This
is because they are not only important indicators of the variety of
physical effects that may influence helioseismic inferences in active
regions, but they also enable detailed assessments of the validity of
helioseismic interpretations through numerical forward modeling. In
this article, we provide a critical review of the existing sunspot
models and an overview of numerical methods employed to model wave
propagation through model sunspots. We then carry out a helioseismic
analysis of the sunspot in Active Region 9787 and address the serious
inconsistencies uncovered by Gizon et al. (2009a, 2009b). We find that
this sunspot is most probably associated with a shallow, positive
wave-speed perturbation (unlike the traditional two-layer model)
and that travel-time measurements are consistent with a horizontal
outflow in the surrounding moat.
Title: Excitation of non-radial stellar oscillations by gravitational
waves: a first model
Authors: Siegel, D. M.; Roth, M.
Bibcode: 2010MNRAS.408.1742S
Altcode: 2010MNRAS.tmp.1389S; 2010arXiv1006.4803S; 2010MNRAS.tmp.1347S
The excitation of solar and solar-like g modes in non-relativistic stars
by arbitrary external gravitational wave fields is studied starting
from the full field equations of general relativity. We develop a
formalism that yields the mean-square amplitudes and surface velocities
of global normal modes excited in such a way. The isotropic elastic
sphere model of a star is adopted to demonstrate this formalism and for
calculative simplicity. It is shown that gravitational waves solely
couple to quadrupolar spheroidal eigenmodes and that normal modes
are only sensitive to the spherical component of the gravitational
waves having the same azimuthal order. The mean-square amplitudes in
case of stationary external gravitational waves are given by a simple
expression, a product of a factor depending on the resonant properties
of the star and the power spectral density of the gravitational
waves' spherical accelerations. Both mean-square amplitudes and
surface velocities show a characteristic R8-dependence
(effective R2-dependence) on the radius of the star. This
finding increases the relevance of this excitation mechanism in case
of stars larger than the Sun.
Title: Surface Waves in Solar Granulation Observed with SUNRISE
Authors: Roth, M.; Franz, M.; Bello González, N.; Martínez Pillet,
V.; Bonet, J. A.; Gandorfer, A.; Barthol, P.; Solanki, S. K.;
Berkefeld, T.; Schmidt, W.; del Toro Iniesta, J. C.; Domingo, V.;
Knölker, M.
Bibcode: 2010ApJ...723L.175R
Altcode: 2010arXiv1009.4790R
Solar oscillations are expected to be excited by turbulent flows in
the intergranular lanes near the solar surface. Time series recorded
by the IMaX instrument on board the SUNRISE observatory reveal solar
oscillations at high spatial resolution, which allow the study of
the properties of oscillations with short wavelengths. We analyze
two time series with synchronous recordings of Doppler velocity and
continuum intensity images with durations of 32 minutes and 23 minutes,
respectively, recorded close to the disk center of the Sun to study
the propagation and excitation of solar acoustic oscillations. In
the Doppler velocity data, both the standing acoustic waves and the
short-lived, high-degree running waves are visible. The standing
waves are visible as temporary enhancements of the amplitudes of the
large-scale velocity field due to the stochastic superposition of
the acoustic waves. We focus on the high-degree small-scale waves by
suitable filtering in the Fourier domain. Investigating the propagation
and excitation of f- and p 1-modes with wavenumbers k>1.4
Mm-1, we also find that exploding granules contribute to
the excitation of solar p-modes in addition to the contribution of
intergranular lanes.
Title: Erratum: Erratum to: Helioseismology of Sunspots: A Case
Study of NOAA Region 9787
Authors: Gizon, L.; Schunker, H.; Baldner, C. S.; Basu, S.; Birch,
A. C.; Bogart, R. S.; Braun, D. C.; Cameron, R.; Duvall, T. L.;
Hanasoge, S. M.; Jackiewicz, J.; Roth, M.; Stahn, T.; Thompson, M. J.;
Zharkov, S.
Bibcode: 2010SSRv..156..257G
Altcode: 2010SSRv..tmp...99G
No abstract at ADS
Title: Mapping the properties of blue compact dwarf galaxies:
integral field spectroscopy with PMAS
Authors: Cairós, L. M.; Caon, N.; Zurita, C.; Kehrig, C.; Roth, M.;
Weilbacher, P.
Bibcode: 2010A&A...520A..90C
Altcode: 2010arXiv1004.2858C
Context. Blue compact dwarf (BCD) galaxies are low-luminosity, low-metal
content dwarf systems undergoing violent bursts of star formation. They
present a unique opportunity to probe galaxy formation and evolution
and to investigate the process of star formation in a relatively
simple scenario. Spectrophotometric studies of BCDs are essential to
disentangle and characterize their stellar populations.
Aims:
We perform integral field spectroscopy of a sample of BCDs with the
aim of analyzing their morphology, the spatial distribution of some of
their physical properties (excitation, extinction, and electron density)
and their relationship with the distribution and evolutionary state of
the stellar populations.
Methods: Integral field spectroscopy
observations of the sample galaxies were carried out with the Potsdam
Multi-Aperture Spectrophotometer (PMAS) at the 3.5 m telescope at
Calar Alto Observatory. An area 16 arcsec × 16 arcsec in size was
mapped with a spatial sampling of 1 arcsec × 1 arcsec. We obtained
data in the 3590-6996 Å spectral range, with a linear dispersion
of 3.2 Å per pixel. From these data we built two-dimensional maps
of the flux of the most prominent emission lines, of two continuum
bands, of the most relevant line ratios, and of the gas velocity
field. Integrated spectra of the most prominent star-forming regions
and of whole objects within the FOV were used to derive their physical
parameters and the gas metal abundances.
Results: Six galaxies
display the same morphology both in emission line and in continuum maps;
only in two objects, Mrk 32 and Tololo 1434+032, the distributions of
the ionized gas and of the stars differ considerably. In general the
different excitation maps for a same object display the same pattern
and trace the star-forming regions, as expected for objects ionized
by hot stars; only the outer regions of Mrk 32, I Zw 123 and I Zw 159
display higher [S II]/Hα values, suggestive of shocks. Six galaxies
display an inhomogeneous dust distribution. Regarding the kinematics,
Mrk 750, Mrk 206 and I Zw 159 display a clear rotation pattern, while
in Mrk 32, Mrk 475 and I Zw 123 the velocity fields are flat. Tables 3-6 and Figs. 3-9 are only available in electronic form at
http://www.aanda.org
Title: Gamma-Ray Emission Concurrent with the Nova in the Symbiotic
Binary V407 Cygni
Authors: Abdo, A. A.; Ackermann, M.; Ajello, M.; Atwood, W. B.;
Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol,
K.; Bellazzini, R.; Berenji, B.; Blandford, R. D.; Bloom, E. D.;
Bonamente, E.; Borgland, A. W.; Bouvier, A.; Brandt, T. J.; Bregeon,
J.; Brez, A.; Brigida, M.; Bruel, P.; Buehler, R.; Burnett, T. H.;
Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Carrigan,
S.; Casandjian, J. M.; Cecchi, C.; Celik, O.; Charles, E.; Chaty,
S.; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Ciprini, S.; Claus,
R.; Cohen-Tanugi, J.; Conrad, J.; Corbel, S.; Corbet, R.; DeCesar,
M. E.; den Hartog, P. R.; Dermer, C. D.; de Palma, F.; Digel, S. W.;
Donato, D.; do Couto e Silva, E.; Drell, P. S.; Dubois, R.; Dubus,
G.; Dumora, D.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Fortin,
P.; Frailis, M.; Fuhrmann, L.; Fukazawa, Y.; Funk, S.; Fusco, P.;
Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giglietto,
N.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier,
I. A.; Grondin, M. H.; Grove, J. E.; Guiriec, S.; Hadasch, D.; Harding,
A. K.; Hayashida, M.; Hays, E.; Healey, S. E.; Hill, A. B.; Horan, D.;
Hughes, R. E.; Itoh, R.; Jean, P.; Jóhannesson, G.; Johnson, A. S.;
Johnson, R. P.; Johnson, T. J.; Johnson, W. N.; Kamae, T.; Katagiri,
H.; Kataoka, J.; Kerr, M.; Knödlseder, J.; Koerding, E.; Kuss, M.;
Lande, J.; Latronico, L.; Lee, S. H.; Lemoine-Goumard, M.; Garde,
M. L.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano,
P.; Makeev, A.; Mazziotta, M. N.; McConville, W.; McEnery, J. E.;
Mehault, J.; Michelson, P. F.; Mizuno, T.; Moiseev, A. A.; Monte, C.;
Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakamori,
T.; Naumann-Godo, M.; Nestoras, I.; Nolan, P. L.; Norris, J. P.; Nuss,
E.; Ohno, M.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orlando, E.; Ormes,
J. F.; Ozaki, M.; Paneque, D.; Panetta, J. H.; Parent, D.; Pelassa,
V.; Pepe, M.; Pesce-Rollins, M.; Piron, F.; Porter, T. A.; Rainó, S.;
Rando, R.; Ray, P. S.; Razzano, M.; Razzaque, S.; Rea, N.; Reimer, A.;
Reimer, O.; Reposeur, T.; Ripken, J.; Ritz, S.; Romani, R. W.; Roth,
M.; Sadrozinski, H. F.; Sander, A.; Parkinson, P. M.; Scargle, J. D.;
Schinzel, F. K.; Sgrò, C.; Shaw, M. S.; Siskind, E. J.; Smith, D. A.;
Smith, P. D.; Sokolovsky, K. V.; Spandre, G.; Spinelli, P.; Stawarz,
Ł.; Strickman, M. S.; Suson, D. J.; Takahashi,, H.; Takahashi, T.;
Tanaka, T.; Tanaka, Y.; Thayer, J. B.; Thayer, J. G.; Thompson, D. J,
Tibaldo, L.; Torres, D. F.; Tosti, G.; Tramacere, A.; Uchiyama, Y.;
Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vilchez, N.; Vitale,
V.; Waite, A. P.; Wallace, E.; Wang, P.; Winer, B. L.; Wolff, M. T.;
Wood, K. S.; Yang, Z.; Ylinen, T.; Ziegler, M.; Maehara, H.; Nishiyama,
K.; Kabashima, F.; Bach, U.; Bower, G. C.; Falcone, A.; Forster,
J. R.; Henden, A.; Kawabata, K. S.; Koubsky, P.; Mukai, K.; Nelson,
T.; Oates, S. R.; Sakimoto, K.; Sasada, M.; Shenavrin, V. I.; Shore,
S. N.; Skinner, G. K.; Sokoloski, J.; Stroh, M.; Tatarnikov, A. M.;
Uemura, M.; Wahlgren, G. M.; Yamanaka, M.; Fermi LAT Collaboration
Bibcode: 2010Sci...329..817A
Altcode: 2010arXiv1008.3912T; 2010Sci...329..817F
Novae are thermonuclear explosions on a white dwarf surface fueled by
mass accreted from a companion star. Current physical models posit that
shocked expanding gas from the nova shell can produce x-ray emission,
but emission at higher energies has not been widely expected. Here,
we report the Fermi Large Area Telescope detection of variable
γ-ray emission (0.1 to 10 billion electron volts) from the recently
detected optical nova of the symbiotic star V407 Cygni. We propose
that the material of the nova shell interacts with the dense ambient
medium of the red giant primary and that particles can be accelerated
effectively to produce π0 decay γ-rays from proton-proton
interactions. Emission involving inverse Compton scattering of the
red giant radiation is also considered and is not ruled out.
Title: Sensitivity of the sub-photospheric flow fields inferred from
ring-diagram analysis to the change on the solar model
Authors: Zaatri, A.; Provost, J.; Corbard, T.; Roth, M.
Bibcode: 2010Ap&SS.328..135Z
Altcode: 2007arXiv0704.2294Z; 2009Ap&SS.tmp..200Z
We study the effect of the change of solar model parameters on the
measurements of the horizontal velocity flow components based on the
analysis of high-degree modes using the ring-diagram local helioseismic
technique. We show that changing the equation of state, opacities,
surface heavy-element abundances or the modeling of convection do
not affect the sub-photospheric flow field measurements. However,
the modeling of outermost layers can affect the measurements if an
important amount of high radial order modes (high-frequency modes)
are included in the analysis.
Title: GNOSIS: an OH suppression unit for near-infrared spectrographs
Authors: Ellis, S. C.; Bland-Hawthorn, J.; Lawrence, J. S.; Bryant,
J.; Haynes, R.; Horton, A.; Lee, S.; Leon-Saval, S.; Löhmannsröben,
Hans-Gerd; Mladenoff, J.; O'Byrne, J.; Rambold, W.; Roth, M.; Trinh, C.
Bibcode: 2010SPIE.7735E..16E
Altcode: 2010SPIE.7735E..40E
GNOSIS is an OH suppression unit to be used in conjunction with existing
spectrographs. The OH suppression is achieved using fibre Bragg gratings
(FBGs), and will deliver the darkest near-infrared background of any
ground-based instrument. Laboratory and on-sky tests demonstrate
that FBGs can suppress OH lines by 30dB whilst maintaing > 90%
throughput between the lines, resulting in a 4 mag decrease in the
background. In the first implementation GNOSIS will feed IRIS2 on the
AAT. It will consist of a seven element lenslet array, covering 1.4"
on the sky, and will suppress the 103 brightest OH lines between 1.47
and 1.70 μm. Future upgrades will include J-band suppression and
implementation on an 8m telescope.
Title: The MUSE project from the dream toward reality
Authors: Callier, P.; Accardo, M.; Adjali, L.; Anwand, H.; Bacon, R.;
Bauer, S. M.; Biswas, I.; Boudon, D.; Brau-Nogué, S.; Brotons, L.;
Capoani, L.; Contini, T.; Daguisé, E.; Deiries, S.; Delabre, B.;
Dubois, J. -P.; Dupieux, M.; Dupuis, C.; Fechner, T.; Fleischmann,
A.; François, M.; Gallou, G.; Gharsa, T.; Glindemann, A.; Gojak, D.;
Hansali, G.; Hahn, T.; Jarno, A.; Kelz, A.; Koehler, C.; Kosmalski, J.;
Laurent, F.; Le Floch, M.; Lizon, J. -L.; Loupias, M.; Manescau, A.;
Monstein, C.; Nicklas, H.; Olaya, J. -C.; Parès, L.; Pasquini, L.;
Pécontal-Rousset, A.; Petit, C.; Popow, E.; Reiss, R.; Remillieux,
A.; Renault, E.; Roth, M.; Rupprecht, G.; Serre, D.; Streicher, O.;
Stuik, R.; Vernet, J.; Weilbacher, P.; Wisotzki, L.; Yerle, N.
Bibcode: 2010SPIE.7738E..0SC
Altcode: 2010SPIE.7738E..24C
MUSE (Multi Unit Spectroscopic Explorer) is a second generation
instrument developed for ESO (European Southern Observatory) to be
installed on the VLT (Very Large Telescope) in year 2012. The MUSE
project is supported by a European consortium of 7 institutes. After
a successful Final Design Review the project is now facing a turning
point which consist in shifting from design to manufacturing, from
calculation to test, ... from dream to reality. At the start, many
technical and management challenges were there as well as unknowns. They
could all be derived of the same simple question: How to deal with
complexity? The complexity of the instrument, of the work to de done,
of the organization, of the interfaces, of financial and procurement
rules, etc. This particular moment in the project life cycle is the
opportunity to look back and evaluate the management methods implemented
during the design phase regarding this original question. What are
the lessons learn? What has been successful? What could have been
done differently? Finally, we will look forward and review the main
challenges of the MAIT (Manufacturing Assembly Integration and Test)
phase which has just started as well as the associated new processes
and evolutions needed.
Title: The MUSE second-generation VLT instrument
Authors: Bacon, R.; Accardo, M.; Adjali, L.; Anwand, H.; Bauer, S.;
Biswas, I.; Blaizot, J.; Boudon, D.; Brau-Nogue, S.; Brinchmann, J.;
Caillier, P.; Capoani, L.; Carollo, C. M.; Contini, T.; Couderc,
P.; Daguisé, E.; Deiries, S.; Delabre, B.; Dreizler, S.; Dubois,
J.; Dupieux, M.; Dupuy, C.; Emsellem, E.; Fechner, T.; Fleischmann,
A.; François, M.; Gallou, G.; Gharsa, T.; Glindemann, A.; Gojak, D.;
Guiderdoni, B.; Hansali, G.; Hahn, T.; Jarno, A.; Kelz, A.; Koehler,
C.; Kosmalski, J.; Laurent, F.; Le Floch, M.; Lilly, S. J.; Lizon,
J. -L.; Loupias, M.; Manescau, A.; Monstein, C.; Nicklas, H.; Olaya,
J. -C.; Pares, L.; Pasquini, L.; Pécontal-Rousset, A.; Pelló, R.;
Petit, C.; Popow, E.; Reiss, R.; Remillieux, A.; Renault, E.; Roth,
M.; Rupprecht, G.; Serre, D.; Schaye, J.; Soucail, G.; Steinmetz, M.;
Streicher, O.; Stuik, R.; Valentin, H.,; Vernet, J.; Weilbacher, P.;
Wisotzki, L.; Yerle, N.
Bibcode: 2010SPIE.7735E..08B
Altcode: 2010SPIE.7735E...7B
Summary: The Multi Unit Spectroscopic Explorer (MUSE) is a
second-generation VLT panoramic integral-field spectrograph currently
in manufacturing, assembly and integration phase. MUSE has a field of
1x1 arcmin2 sampled at 0.2x0.2 arcsec2 and is
assisted by the VLT ground layer adaptive optics ESO facility using
four laser guide stars. The instrument is a large assembly of 24
identical high performance integral field units, each one composed
of an advanced image slicer, a spectrograph and a 4kx4k detector. In
this paper we review the progress of the manufacturing and report the
performance achieved with the first integral field unit.
Title: Fermi Gamma-Ray Imaging of a Radio Galaxy
Authors: Abdo, A. A.; Ackermann, M.; Ajello, M.; Atwood, W. B.;
Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Baughman,
B. M.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R. D.;
Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bregeon, J.; Brez, A.;
Brigida, M.; Bruel, P.; Burnett, T. H.; Buson, S.; Caliandro, G. A.;
Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; Cavazzuti, E.;
Cecchi, C.; Çelik, Ö.; Chekhtman, A.; Cheung, C. C.; Chiang, J.;
Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Colafrancesco, S.; Cominsky,
L. R.; Conrad, J.; Costamante, L.; Cutini, S.; Davis, D. S.; Dermer,
C. D.; de Angelis, A.; de Palma, F.; Digel, S. W.; do Couto e Silva,
E.; Drell, P. S.; Dubois, R.; Dumora, D.; Farnier, C.; Favuzzi,
C.; Fegan, S. J.; Finke, J.; Focke, W. B.; Fortin, P.; Fukazawa,
Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.;
Georganopoulos, M.; Germani, S.; Giebels, B.; Giglietto, N.; Giordano,
F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grove,
J. E.; Guillemot, L.; Guiriec, S.; Hanabata, Y.; Harding, A. K.;
Hayashida, M.; Hays, E.; Hughes, R. E.; Jackson, M. S.; Jóhannesson
G.; Johnson, S.; Johnson, T. J.; Johnson, W. N.; Kamae, T.; Katagiri,
H.; Kataoka, J.; Kawai, N.; Kerr, M.; Knödlseder, J.; Kocian, M. L.;
Kuss, M.; Lande, J.; Latronico, L.; Lemoine-Goumard, M.; Longo, F.;
Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.;
Makeev, A.; Mazziotta, M. N.; McConville, W.; McEnery, J. E.; Meurer,
C.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.;
Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia,
S.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohsugi, T.; Omodei, N.;
Orlando, E.; Ormes, J. F.; Paneque, D.; Parent, D.; Pelassa, V.; Pepe,
M.; Pesce-Rollins, M.; Piron, F.; Porter, T. A.; Rainò, S.; Rando,
R.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Reposeur, T.;
Ritz, S.; Rochester, L. S.; Rodriguez, A. Y.; Romani, R. W.; Roth, M.;
Ryde, F.; Sadrozinski, H. F. -W.; Sambruna, R.; Sanchez, D.; Sander,
A.; Saz Parkinson, P. M.; Scargle, J. D.; Sgrò, C.; Siskind, J.;
Smith, D. A.; Smith, P. D.; Spandre, G.; Spinelli, P.; Starck, J. -L.;
Stawarz, L.; Strickman, M. S.; Suson, D. J.; Tajima, H.; Takahashi,
H.; Takahashi, T.; Tanaka, T.; Thayer, J. B.; Thayer, J. G.; Thompson,
D. J.; Tibaldo, L.; Torres, D. F.; Tosti, G.; Tramacere, A.; Uchiyama,
Y. Usher, T. L.; Vasileiou, V.; Vilchez, N.; Vitale, V.; Waite, A. P.;
Wallace, E.; Wang, P.; Winer, B. L.; Wood, K. S.; Ylinen, T.; Ziegler,
M.; Hardcastle, M. J.; Kazanas, D.; Fermi LAT Collaboration
Bibcode: 2010Sci...328..725A
Altcode: 2010arXiv1006.3986T; 2010Sci...328..725F; 2010Sci...328..725.
The Fermi Gamma-ray Space Telescope has detected the γ-ray glow
emanating from the giant radio lobes of the radio galaxy Centaurus
A. The resolved γ-ray image shows the lobes clearly separated from
the central active source. In contrast to all other active galaxies
detected so far in high-energy γ-rays, the lobe flux constitutes
a considerable portion (greater than one-half) of the total source
emission. The γ-ray emission from the lobes is interpreted as
inverse Compton-scattered relic radiation from the cosmic microwave
background, with additional contribution at higher energies from the
infrared-to-optical extragalactic background light. These measurements
provide γ-ray constraints on the magnetic field and particle energy
content in radio galaxy lobes, as well as a promising method to probe
the cosmic relic photon fields.
Title: Estimating the solar meridional flow by normal mode
decomposition of long time series of Doppler imaging data
Authors: Doerr, Hans-Peter; Roth, Markus; Krieger, Lars
Bibcode: 2010EGUGA..1210939D
Altcode:
Although investigations have been carried out for many decades
the solar magnetic cycle is not yet understood in all its basic
properties and it still is one of the main research foci of today's
solar physics. An important ingredient to most dynamic dynamo models
is the solar meridional flow; on the surface of each hemisphere,
a polewards flow in the order of 10 - 20 m/s can be measured with
different techniques. From mass conservation, one expects a much slower
equatorwards return-flow in deeper layers of the solar convection zone
which reaches down to about 200 mega meters below the surface. Numerous
attempts have been made to derive the depth profile of the flow using a
variety of helioseismic techniques (e.g. Giles, P.M., 2000). While most
results agree well about the horizontal velocity structures in the upper
20 Mm, sometimes contrary findings have been published for the lower
parts of the convection zone. We use a Fourier-Legendre decomposition
of the surface wave field generated by the solar normal modes into
directly opposed travelling wave fields, corresponding a modification
of a method suggested earlier by Braun & Fan (1998). The partition
allows for the estimation of the frequency difference, caused by the
horizontal meridional flow between waves that propagate polewards
and equatorwards respectively. These frequency shifts are used
to determine the meridional flow profile as a function of depth
and latitude by a SOLA (Subtractive Optimally Localized Averaging)
inversion method. Because low-degree modes penetrate deeper into the
solar interior than high-degree modes, decomposing the seismic wave
field within large patches on the solar surface allows to probe a
large fraction of the solar convection zone for the average meridional
flow. Smaller patches allow us to study the latitudinal dependence of
the flow in higher layers and also a direct comparison of our findings
with other methods like ring-diagram analysis. For our analysis, we
use Doppler imaging data provided by the ground based instruments
of the GONG (Global Oscillation Network Group) network as well as
from the MDI (Michelson Doppler Imager) instrument aboard the SOHO
(Solar and Heliospheric Observatory) spacecraft. Both observatories
now provide data spanning about one decade and thus allow us to study
the variation with time of the meridional flow during the past solar
cycle. Beside a short but broad overview about the significance of the
meridional flow for modelling the solar internal processes, several new
results of the ongoing analysis are presented. We are able to extend
the seismic probing of the solar interior beyond those shallow regions
that were accessible to other methods.
Title: Hybrid γ Doradus-δ Scuti Pulsators: New Insights into the
Physics of the Oscillations from Kepler Observations
Authors: Grigahcène, A.; Antoci, V.; Balona, L.; Catanzaro, G.;
Daszyńska-Daszkiewicz, J.; Guzik, J. A.; Handler, G.; Houdek,
G.; Kurtz, D. W.; Marconi, M.; Monteiro, M. J. P. F. G.; Moya, A.;
Ripepi, V.; Suárez, J. -C.; Uytterhoeven, K.; Borucki, W. J.; Brown,
T. M.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Jenkins, J. M.;
Kjeldsen, H.; Koch, D.; Bernabei, S.; Bradley, P.; Breger, M.; Di
Criscienzo, M.; Dupret, M. -A.; García, R. A.; García Hernández, A.;
Jackiewicz, J.; Kaiser, A.; Lehmann, H.; Martín-Ruiz, S.; Mathias,
P.; Molenda-Żakowicz, J.; Nemec, J. M.; Nuspl, J.; Paparó, M.;
Roth, M.; Szabó, R.; Suran, M. D.; Ventura, R.
Bibcode: 2010ApJ...713L.192G
Altcode: 2010arXiv1001.0747G
Observations of the pulsations of stars can be used to infer their
interior structure and test theoretical models. The main-sequence
γ Doradus (Dor) and δ Scuti (Sct) stars with masses 1.2-2.5 M
sun are particularly useful for these studies. The γ
Dor stars pulsate in high-order g-modes with periods of order 1
day, driven by convective blocking at the base of their envelope
convection zone. The δ Sct stars pulsate in low-order g- and p-modes
with periods of order 2 hr, driven by the κ mechanism operating in
the He II ionization zone. Theory predicts an overlap region in the
Hertzsprung-Russell diagram between instability regions, where "hybrid"
stars pulsating in both types of modes should exist. The two types of
modes with properties governed by different portions of the stellar
interior provide complementary model constraints. Among the known γ
Dor and δ Sct stars, only four have been confirmed as hybrids. Now,
analysis of combined Quarter 0 and Quarter 1 Kepler data for hundreds of
variable stars shows that the frequency spectra are so rich that there
are practically no pure δ Sct or γ Dor pulsators, i.e., essentially
all of the stars show frequencies in both the δ Sct and the γ Dor
frequency range. A new observational classification scheme is proposed
that takes into account the amplitude as well as the frequency and is
applied to categorize 234 stars as δ Sct, γ Dor, δ Sct/γ Dor or
γ Dor/δ Sct hybrids.
Title: The Asteroseismic Potential of Kepler: First Results for
Solar-Type Stars
Authors: Chaplin, W. J.; Appourchaux, T.; Elsworth, Y.; García,
R. A.; Houdek, G.; Karoff, C.; Metcalfe, T. S.; Molenda-Żakowicz,
J.; Monteiro, M. J. P. F. G.; Thompson, M. J.; Brown, T. M.;
Christensen-Dalsgaard, J.; Gilliland, R. L.; Kjeldsen, H.; Borucki,
W. J.; Koch, D.; Jenkins, J. M.; Ballot, J.; Basu, S.; Bazot, M.;
Bedding, T. R.; Benomar, O.; Bonanno, A.; Brandão, I. M.; Bruntt,
H.; Campante, T. L.; Creevey, O. L.; Di Mauro, M. P.; Doǧan,
G.; Dreizler, S.; Eggenberger, P.; Esch, L.; Fletcher, S. T.;
Frandsen, S.; Gai, N.; Gaulme, P.; Handberg, R.; Hekker, S.; Howe,
R.; Huber, D.; Korzennik, S. G.; Lebrun, J. C.; Leccia, S.; Martic,
M.; Mathur, S.; Mosser, B.; New, R.; Quirion, P. -O.; Régulo, C.;
Roxburgh, I. W.; Salabert, D.; Schou, J.; Sousa, S. G.; Stello, D.;
Verner, G. A.; Arentoft, T.; Barban, C.; Belkacem, K.; Benatti, S.;
Biazzo, K.; Boumier, P.; Bradley, P. A.; Broomhall, A. -M.; Buzasi,
D. L.; Claudi, R. U.; Cunha, M. S.; D'Antona, F.; Deheuvels, S.;
Derekas, A.; García Hernández, A.; Giampapa, M. S.; Goupil, M. J.;
Gruberbauer, M.; Guzik, J. A.; Hale, S. J.; Ireland, M. J.; Kiss,
L. L.; Kitiashvili, I. N.; Kolenberg, K.; Korhonen, H.; Kosovichev,
A. G.; Kupka, F.; Lebreton, Y.; Leroy, B.; Ludwig, H. -G.; Mathis, S.;
Michel, E.; Miglio, A.; Montalbán, J.; Moya, A.; Noels, A.; Noyes,
R. W.; Pallé, P. L.; Piau, L.; Preston, H. L.; Roca Cortés, T.;
Roth, M.; Sato, K. H.; Schmitt, J.; Serenelli, A. M.; Silva Aguirre,
V.; Stevens, I. R.; Suárez, J. C.; Suran, M. D.; Trampedach, R.;
Turck-Chièze, S.; Uytterhoeven, K.; Ventura, R.; Wilson, P. A.
Bibcode: 2010ApJ...713L.169C
Altcode: 2010arXiv1001.0506C
We present preliminary asteroseismic results from Kepler on three G-type
stars. The observations, made at one-minute cadence during the first
33.5 days of science operations, reveal high signal-to-noise solar-like
oscillation spectra in all three stars: about 20 modes of oscillation
may be clearly distinguished in each star. We discuss the appearance of
the oscillation spectra, use the frequencies and frequency separations
to provide first results on the radii, masses, and ages of the stars,
and comment in the light of these results on prospects for inference
on other solar-type stars that Kepler will observe.
Title: Numerical simulations of wave propagation in the solar
chromosphere .
Authors: Nutto, C.; Steiner, O.; Roth, M.
Bibcode: 2010MmSAI..81..744N
Altcode: 2010arXiv1009.5607N
We present two-dimensional simulations of wave propagation in a
realistic, non-stationary model of the solar atmosphere. This model
shows a granular velocity field and magnetic flux concentrations in
the intergranular lanes similar to observed velocity and magnetic
structures on the Sun and takes radiative transfer into account. We present three cases of magneto-acoustic wave propagation through
the model atmosphere, where we focus on the interaction of different
magneto-acoustic wave modes at the layer of similar sound and Alfvén
speeds, which we call the equipartition layer. At this layer acoustic
and magnetic mode can exchange energy depending on the angle between the
wave vector and the magnetic field vector. Our results show that
above the equipartition layer and in all three cases the fast magnetic
mode is refracted back into the solar atmosphere. Thus, the magnetic
wave shows an evanescent behavior in the chromosphere. The acoustic
mode, which travels along the magnetic field in the low plasma-beta
regime, can be a direct consequence of an acoustic source within or
outside the low-beta regime, or it can result from conversion of the
magnetic mode, possibly from several such conversions when the wave
travels across a series of equipartition layers.
Title: Gapfilling interrupted helioseismic data with the EM algorithm
Authors: Roth, M.; Zhugzhda, Yu. D.
Bibcode: 2010AstL...36...64R
Altcode: 2010PAZh...36...66R
Helioseismic data are often interrupted by gaps, which diminish
the quality of the data. In the frequency domain, these gaps lead
to systematical effects with misleading interpretation of the power
spectra. We propose a gap filling method that is based on modeling
solar oscillation data with a statistical process, i.e., the stochastic
nature of a single oscillation is taken into account by regarding it as
realization of an autoregressive (AR) processes of second order. From
the whole oscillation time series given as the superposition of the
realization of many excited modes, the process parameters are estimated
via the expectation maximization (EM) algorithm. Then the estimated
model is used to predict the further course of the oscillatory
process during occurring gaps. We demonstrate the applicability of
this procedure on the basis of both simulations and data obtained with
the DIFOS satellite experiment suffering from gaps of 30 min duration
occurring regularly every 90 min due to the orbit around the Earth.
Title: Flexible Tools for Accessing the Cluster Archives
Authors: Gamby, E.; De Keyser, J.; Roth, M.
Bibcode: 2010ASSP...11..233G
Altcode: 2010caa..book..233G
Nowadays, multi-spacecraft analysis is becoming common practice. The
lack of homogeneity in data archive structure, access types and
data formats results in a lot of time spent to search, retrieve and
reformat data. We have developed a software model dealing with these
issues. In this model, we integrate an abstraction layer for accessing
and caching archive data from different providers. A second abstraction
layer allows converting the specific data formats into a common
working format. This model has been implemented in the MIM software,
developed by the Belgian Institute for Space Aeronomy. In particular,
it provides a framework for accessing the CAA (Cluster Active Archive)
and for exploiting Cluster data with multipoint analysis tools such as,
e.g., gradient computation and magnetopause reconstruction.
Title: Time-Frequency Analysis of Global Solar Oscillation Time Series
Authors: Schad, A.; Roth, M.; Timmer, J.
Bibcode: 2009ASPC..416..257S
Altcode:
Changes of the frequency content of solar oscillations reflect dynamical
changes in the solar interior. We investigated the instantaneous
amplitude and frequency as measures to quantify such changes from
global solar oscillation time series.
Title: Data Assimilation and Helio- & Asteroseismology
Authors: Roth, M.
Bibcode: 2009ASPC..416..501R
Altcode:
Data assimilation is an analysis technique in which observed
information is accumulated into a model state by taking advantage
of consistency constraints with laws of time evolution and physical
properties. Practically, data assimilation is carried out by estimating
an unknown probability density function recursively over time using
incoming measurements and a model for a stochastic process. The true
state is assumed to be unobservable and the measurements are the
observed states of a hidden model. In this contribution I will give
a short overview on data assimilation techniques and suggest how data
assimilation could be useful for helio- and asteroseismology.
Title: Measurement of the Fermi-LAT Localization Performance
Authors: Burnett, T. H.; Kerr, M.; Roth, M.
Bibcode: 2009arXiv0912.3855B
Altcode:
We present results of a study of the localization capability
of Fermi-LAT, using a large set of blazars with precise radio
locations. Since the width of the PSF decreases with energy, the
performance is typically dominated by a few high energy photons, so it
is important to properly characterize the high-energy PSF. Using such
data, we have found a need to modify the pre-launch high-energy (greater
than a few GeV) PSF derived from extensive Monte Carlo simulations of
particle interactions in the LAT; the resulting data-based PSF is shown
Title: Mapping the starburst in blue compact dwarf galaxies. PMAS
integral field spectroscopy of Mrk 1418
Authors: Cairós, L. M.; Caon, N.; Zurita, C.; Kehrig, C.; Weilbacher,
P.; Roth, M.
Bibcode: 2009A&A...507.1291C
Altcode: 2009arXiv0908.1305C
Aims: By means of optical integral field spectroscopy observations,
we aim to differentiate and characterize the starburst component in
the blue compact dwarf (BCD) galaxy Mrk 1418. In particular we propose
to study the stellar and ionized gas morphology, to investigate the
ionization mechanism(s) acting in the interstellar medium, and to
derive the physical parameters and abundances of the ionized gas.
Methods: Integral field spectroscopy observations of Mrk 1418
were carried out with the Potsdam multi-aperture spectrophotometer
(PMAS) at the 3.5 m telescope at Calar Alto Observatory. The central
16 arcsec×16 arcsec (1.14 × 1.14 kpc2 at the distance
of Mrk 1418) were mapped with a spatial sampling of 1 arcsec; we took
data in the 3590-6996 Å spectral range, with a linear dispersion of
3.2 Å per pixel. The seeing was about 1farcs5. From these data we
built maps of the most prominent emission lines, namely [O ii], Hβ,
[O iii], Hα, [N ii], and [S ii], as well as of several continuum
bands, plus maps of the main line ratios: [O iii]/Hβ, [N ii]/Hα, [S
ii]/Hα, and Hα/Hβ, and derived the physical parameters and gaseous
metal abundances of the different star-forming regions detected in the
field of view.
Results: Mrk 1418 shows a distorted morphology
both in the continuum and in the ionized gas maps; the current star-
formation episode is taking place in five knots, distributed around the
nucleus of the galaxy. The interstellar medium surrounding these knots
is photo-ionized by stars, with no clear evidence for other excitation
mechanisms. The galaxy displays an inhomogeneous dust distribution,
with the high Hα/Hβ ratio in the central areas indicating a large
amount of dust. The oxygen abundances derived for the individual
star-forming knots are very similar, suggesting that the ionized
interstellar medium is chemically homogeneous in O/H over spatial scales
of hundreds of parsecs. This abundance (Z ≈ 0.4 Z⊙ from
the empirical calibrations) places Mrk 1418 among the high metallicity
BCD group.
Conclusions: These findings show the advantages
of IFS when investigating the properties of such complex objects as
BCDs, with an asymmetric star-forming component. Only a bidimensional
mapping of their central regions allows approaching such questions as
the star formation processes in BCDs, the star-forming history of the
individual starburst knots, or the abundance gradients. Based on
observations obtained at the German-Spanish Astronomical Center, Calar
Alto, operated by the Max-Planck-Institut fur Astronomie Heidelberg
jointly with the Spanish National Commission for Astronomy.
Title: Comparison of the sidereal angular velocity of subphotospheric
layers and small bright coronal structures during the declining
phase of solar cycle 23
Authors: Zaatri, A.; Wöhl, H.; Roth, M.; Corbard, T.; Brajša, R.
Bibcode: 2009A&A...504..589Z
Altcode: 2009arXiv0907.4099Z
Context: We compare solar differential rotation of subphotospheric
layers derived from local helioseismology analysis of GONG++
dopplergrams and the one derived from tracing small bright coronal
structures (SBCS) using EIT/SOHO images for the period August
2001-December 2006, which correspond to the declining phase of solar
cycle 23.
Aims: The study aims to find a relationship between
the rotation of the SBCS and the subphotospheric angular velocity. The
north-south asymmetries of both rotation velocity measurements are also
investigated.
Methods: Subphotospheric differential rotation was
derived using ring-diagram analysis of GONG++ full-disk dopplergrams of
1 min cadence. The coronal rotation was derived by using an automatic
method to identify and track the small bright coronal structures in
EIT full-disk images of 6 h cadence.
Results: We find that the
SBCS rotate faster than the considered upper subphotospheric layer
(3 Mm) by about 0.5 deg/day at the equator. This result joins the
results of several other magnetic features (sunspots, plages, faculae,
etc.) with a higher rotation than the solar plasma. The rotation rate
latitudinal gradients of the SBCS and the subphotospheric layers
are very similar. The SBCS motion shows an acceleration of about
0.005°day-1/month during the declining phase of solar cycle
23, whereas the angular velocity of subsurface layers does not display
any evident variation with time, except for the well known torsional
oscillation pattern. Finally, both subphotospheric and coronal rotations
of the southern hemisphere are predominantly larger than those of the
northern hemisphere. At latitudes where the north-south asymmetry of
the angular velocity increases (decreases) with activity for the SBCS,
it decreases (increases) for subphotospheric layers.
Title: On the NIR counterpart candidate to XTE J1652-453
Authors: Torres, M. A. P.; Steeghs, D.; Jonker, P. G.; McClintock,
J. E.; Morrell, N.; Roth, M.
Bibcode: 2009ATel.2190....1T
Altcode:
We report on near-infrared follow-up observations of the field
containing the currently active X-ray transient XTE J1652-453 (Markwardt
et al. ATel #2107, #2120). A Ks= 16.9 +/- 0.3 mag NIR counterpart
candidate has been suggested on the basis of its coincidence with
the radio localization for the X-ray source (Calvelo et al. ATel
#2135, Reynolds et al. ATel #2125). We have acquired a series of 15s
Ks-band images on 2009 Jul 15 23:02 - 23:14 UT and again on 2009 Aug
28 23:33-23:46 using the PANIC camera attached to the 6.5m Magellan
Baade telescope at Las Campanas observatory.
Title: On the Distribution of Dust in the ``Born-again'' Planetary
Nebula A 30
Authors: Kerber, F.; Roth, M.; Rauch, T.; Ageorges, N.; Clayton,
G. C.; De Marco, O.; Koller, J.
Bibcode: 2009ASPC..412..235K
Altcode:
The planetary nebula (PN) A30 consists of two nebular shells, one
old, spherical, hydrogen-rich PN and a second, younger, H-poor, and
dust-rich nebula which is the result of a very late thermal pulse
(VLTP), a helium shell flash that occurred long after the central
star (CS) had left the asymptotic giant branch (AGB). During the VLTP
the CS returned to the AGB and became a ``born-again'' giant for a
few years. During this extremely fast episode of stellar evolution
a final mass-loss phase created the second, dusty PN a few thousand
years ago. Such a VLTP should occur in 20% of all post-AGB stars
according to theory but only a handful of ``born-again'' PNe are
known, a discrepancy that remains unexplained so far. Moreover, the
knots in A30 have been reported to be O-rich in clear disagreement
with the C-rich composition predicted for a VLTP. In the case of A30
the ``born-again'' PN is highly filamentary and the individual knots
clearly show signs of erosion from the fast wind of the -- yet again --
hot CS, such as ``cometary'' tails. While optical imaging (gas emission)
obtained with the HST has provided excellent spatial resolution, near
infrared imaging (dust emission) had been very limited in resolution so
far. Our new PANIC/Magellan data quite literally shows the other side of
the coin and as a consequence, for the first time we are able to shed
light on the complex interplay between gas and dust in this PN. A30
forms an evolutionary sequence with V4334 Sgr (10 yrs after the flash)
and V605 Aql (100 yrs) and, hence, provides valuable insight into the
physics of the still poorly understood ``born-again'' PNe. This
paper includes data gathered with the 6.5 meter Magellan Telescopes
located at Las Campanas Observatory, Chile.
Title: A magnetospheric generator driving ion and electron
acceleration and electric currents in a discrete auroral arc observed
by Cluster and DMSP
Authors: Echim, M. M.; Maggiolo, R.; Roth, M.; De Keyser, J.
Bibcode: 2009GeoRL..3612111E
Altcode:
Simultaneous observations on April 28, 2001 by Cluster and DMSP-F14
reveal a stable discrete auroral arc and fluxes of field-aligned
accelerated electrons and ions coincident with a magnetospheric plasma
interface at an altitude of 4.5 RE in the dusk sector. We
compare satellite data with a quasi-stationary magnetosphere-ionosphere
coupling model based on a Vlasov solution for the magnetospheric
generator. The model provides a self-consistent magnetospheric
electric potential matching the Cluster observations. The ionospheric
potential is derived from the current continuity equation and gives
a field-aligned potential drop and a flux of precipitating energy in
agreement with the DMSP data. Model results and data analysis suggest
a quasi-stationary field-aligned acceleration of auroral electrons
and ions with a magnetospheric generator. We associate the generator
with the convergent perpendicular electric field at the interface of
the plasma sheet boundary layer with the lobe or at the inner edge of
the low latitude boundary layer.
Title: Coordinated Observations of Auroral Arcs with ALIS and EISCAT
Authors: Lamy, H.; Simon, C.; Gustavsson, B.; de Keyser, J.; Echim,
M.; Sergienko, T.; Brandström, U.; Sandahl, I.; Roth, M.
Bibcode: 2009AGUSMSM22A..05L
Altcode:
In March 2008, we carried out a coordinated observation campaign of
auroral arcs between the European Incoherent Scatter Radar (EISCAT)
located in Tromsö, Norway, and the Auroral Large Imaging System (ALIS)
located near Kiruna, Sweden. The ALIS network consists of 5 ground-based
stations equipped with optical cameras observing simultaneously the same
volume of the sky located at altitudes around 90-100 km. From optical
observations, we reconstruct the three-dimensional (3D) volume rate
emissions of the aurora with tomographic-like inversion techniques and
we retrieve a 2D map (in longitude and latitude) of the energy spectra
of precipitating electrons at the top of the ionosphere. From radar
observations, we can also infer the energy spectrum of electrons but
only along the magnetic field line (1D). These results are compared to
test the assumptions used in the models as well as the reconstruction
techniques. We use the energy spectrum of electrons deduced from ALIS
data as input to TRANS4 (a proton-electron kinetic/fluid transport
code) to simulate the density and temperature profiles observed by
EISCAT. The electron energy fluxes are then used to obtain the 2D
field-aligned potential drops between the upper ionosphere and the
magnetosphere by using a Knight-like relationship.
Title: The Carnegie Supernova Project: Analysis of the First Sample
of Low-Redshift Type-Ia Supernovae
Authors: Folatelli, Gaston; Phillips, M. M.; Burns, C. R.; Contreras,
C.; Hamuy, M.; Freedman, W. L.; Persson, S. E.; Stritzinger, M.;
Suntzeff, N. B.; Krisciunas, K.; Boldt, L.; Gonzalez, S.; Krzeminski,
W.; Morrell, N.; Roth, M.; Salgado, F.; Madore, B. F.; Murphy, D.;
Wyatt, P.; Li, W.; Filippenko, A. V.
Bibcode: 2009AAS...21442703F
Altcode:
We present the analysis of the first set of 35 low-redshift (z<0.08)
Type Ia supernovae studied by the Carnegie Supernova Project. The
data consist of densely-sampled, high-precision light curves obtained
with a uniform, well-characterized photometric system comprising the
ugriBVYJHKs bands. We use these data to derive light-curve parameters
and to build template light curves that are applicable for fitting
other Type-Ia supernova data. We calibrate the intrinsic colors at
maximum light. This is used to derive color excesses and thus study
the properties of the reddening law in the host galaxies, with the
advantage of combining optical and NIR bands. We study the calibration
of absolute peak magnitudes in all bands using a two-parameter
bilinear fit to decline rates and colors or, alternatively, color
excesses. We obtain dispersions of 0.1_ 0.2 mag, depending on the
filter--color combinations, and low values of the reddening-law
parameter RV 1_ 2. We further investigate the validity of
Type-Ia supernovae as true standard candles in the NIR, requiring no
correction for decline rate.
Title: Carnegie Supernova Project: First Photometry Data Release of
Type Ia Supernovae
Authors: Contreras, Carlos; Hamuy, M.; Phillips, M. M.; Folatelli,
G.; Suntzeff, N. B.; Persson, S. E.; Stritzinger, M.; Boldt, L.;
Gonzalez, S.; Krzeminski, W.; Morrell, N.; Roth, M.; Salgado, F.;
Maureira, M. J.; Burns, C. R.; Freedman, W. L.; Madore, B.; Murphy,
D.; Wyatt, P.; Li, W.; Filippenko, A. V.
Bibcode: 2009AAS...21442704C
Altcode:
The Carnegie Supernova Project is a five year survey being carried out
at the Las Campanas Observatory to obtain high-quality light curves
of 100 low-redshift Type Ia supernovae in a well-defined photometric
system. In this paper, we present the first release of photometric
data that contains the optical (ugriBV) light curves of 35 Type Ia
supernovae, and near-infrared (YJHKs) light curves for a subset of 25
events. Twenty-eight supernovae have pre-maximum data, and for 15 of
these, the observations begin at least 5 days before B maximum. This
is one of the most accurate datasets of low-z Type Ia supernovae
published to date. When completed, the CSP dataset will constitute
a fundamental reference for precise determinations of cosmological
parameters, and serve as a rich resource for comparison with models
of Type Ia supernovae.
Title: The Carnegie Supernova Project: First Results of the High-z
Campaign
Authors: Burns, Christopher R.; Freedman, W. L.; Wyatt, P.; Phillips,
M. M.; Persson, S. E.; Madore, B. F.; Morell, N.; Roth, M.; Folatelli,
G.; Contreras, C.; Gonzalez, S.; Hamuy, M.; Murphy, D.; Hsiao, E.;
Carlberg, R. G.; Frieman, J. A.; Howell, D. A.; Conley, A.; Perrett,
K.; Sako, M.; Sullivan, M.; Suntzeff, N. B.; Wood-Vasey, M.
Bibcode: 2009AAS...21442702B
Altcode:
One goal of the Carnegie Supernova Project (CSP) is to constrain the
Dark Energy content of the universe using Type Ia supernovae. The CSP
differs from other projects in that it has constructed a rest-frame
i'-band Hubble diagram, thereby reducing the systematic effects of
reddening. We also utilize an independent set of low-redshift Type
Ia supernovae observed in a single, well-characterized photometric
system. In this poster, we present initial results obtained from
the near-infrared observations of 35 high-redshift supernovae. These
data are combined with optical data from other supernova projects to
construct a Hubble diagram which is used to place constrains on the
equation of state parameter, w. Our results are in an agreement with
other groups and are consistent with a cosmological constant.
Title: Helioseismology of Sunspots: A Case Study of NOAA Region 9787
Authors: Gizon, L.; Schunker, H.; Baldner, C. S.; Basu, S.; Birch,
A. C.; Bogart, R. S.; Braun, D. C.; Cameron, R.; Duvall, T. L.;
Hanasoge, S. M.; Jackiewicz, J.; Roth, M.; Stahn, T.; Thompson, M. J.;
Zharkov, S.
Bibcode: 2009SSRv..144..249G
Altcode: 2008SSRv..tmp..188G; 2010arXiv1002.2369G
Various methods of helioseismology are used to study the subsurface
properties of the sunspot in NOAA Active Region 9787. This sunspot
was chosen because it is axisymmetric, shows little evolution during
20-28 January 2002, and was observed continuously by the MDI/SOHO
instrument. AR 9787 is visible on helioseismic maps of the farside
of the Sun from 15 January, i.e. days before it crossed the East
limb. Oscillations have reduced amplitudes in the sunspot at all
frequencies, whereas a region of enhanced acoustic power above 5.5 mHz
(above the quiet-Sun acoustic cutoff) is seen outside the sunspot and
the plage region. This enhanced acoustic power has been suggested to
be caused by the conversion of acoustic waves into magneto-acoustic
waves that are refracted back into the interior and re-emerge as
acoustic waves in the quiet Sun. Observations show that the sunspot
absorbs a significant fraction of the incoming p and f modes around 3
mHz. A numerical simulation of MHD wave propagation through a simple
model of AR 9787 confirmed that wave absorption is likely to be due
to the partial conversion of incoming waves into magneto-acoustic
waves that propagate down the sunspot. Wave travel times and mode
frequencies are affected by the sunspot. In most cases, wave packets
that propagate through the sunspot have reduced travel times. At
short travel distances, however, the sign of the travel-time shifts
appears to depend sensitively on how the data are processed and,
in particular, on filtering in frequency-wavenumber space. We carry
out two linear inversions for wave speed: one using travel-times
and phase-speed filters and the other one using mode frequencies
from ring analysis. These two inversions give subsurface wave-speed
profiles with opposite signs and different amplitudes. The travel-time
measurements also imply different subsurface flow patterns in the
surface layer depending on the filtering procedure that is used. Current
sensitivity kernels are unable to reconcile these measurements, perhaps
because they rely on imperfect models of the power spectrum of solar
oscillations. We present a linear inversion for flows of ridge-filtered
travel times. This inversion shows a horizontal outflow in the upper
4 Mm that is consistent with the moat flow deduced from the surface
motion of moving magnetic features. From this study of AR 9787, we
conclude that we are currently unable to provide a unified description
of the subsurface structure and dynamics of the sunspot.
Title: On solar cycle predictions and reconstructions
Authors: Brajša, R.; Wöhl, H.; Hanslmeier, A.; Verbanac, G.;
Ruždjak, D.; Cliver, E.; Svalgaard, L.; Roth, M.
Bibcode: 2009A&A...496..855B
Altcode:
Context: Generally, there are two procedures for solar cycle
predictions: the empirical methods - statistical methods based on
extrapolations and precursor methods - and methods based on dynamo
models.
Aims: The goal of the present analysis is to forecast
the strength and epochs of the next solar cycle, to investigate proxies
for grand solar minima and to reconstruct the relative sunspot number
in the Maunder minimum.
Methods: We calculate the asymmetry of
the ascending and descending solar cycle phases (Method 1) and use this
parameter as a proxy for solar activity on longer time scales. Further,
we correlate the relative sunspot numbers in the epochs of solar
activity minima and maxima (Method 2) and estimate the parameters of
an autoregressive moving average model (ARMA, Method 3). Finally,
the power spectrum of data obtained with the Method 1 is analysed
and the Methods 1 and 3 are combined.
Results: Signatures of
the Maunder, Dalton and Gleissberg minima were found with Method 1. A
period of about 70 years, somewhat shorter than the Gleissberg period
was identified in the asymmetry data. The maximal smoothed monthly
sunspot number during the Maunder minimum was reconstructed and found
to be in the range 0-35 (Method 1). The estimated Wolf number (also
called the relative sunspot number) of the next solar maximum is in
the range 88-102 (Method 2). Method 3 predicts the next solar maximum
between 2011 and 2012 and the next solar minimum for 2017. Also, it
forecasts the relative sunspot number in the next maximum to be 90
± 27. A combination of the Methods 1 and 3 gives for the next solar
maximum relative sunspot numbers between 78 and 99.
Conclusions:
The asymmetry parameter provided by Method 1 is a good proxy for solar
activity in the past, also in the periods for which no relative sunspot
numbers are available. Our prediction for the next solar cycle No. 24
is that it will be weaker than the last cycle, No. 23. This prediction
is based on various independent methods.
Title: A Prediction for the 24th Solar Cycle
Authors: Brajša, R.; Wöhl, H.; Hanslmeier, A.; Verbanac, G.;
Ruždjak, D.; Cliver, E.; Svalgaard, L.; Roth, M.
Bibcode: 2009CEAB...33...95B
Altcode:
The aim of the present analysis is to forecast the strength of the
next solar maximum of the 24th cycle. We correlate the
relative sunspot numbers in the epochs of solar activity minima and
maxima. Using this method, the estimated relative sunspot number (also
called the Wolf number) of the next solar maximum is in the range 67-81,
i.e., about 40 % below the peak sunspot number of 121 for cycle No. 23.
Title: Helioseismology of Sunspots: A Case Study of NOAA Region 9787
Authors: Gizon, L.; Schunker, H.; Baldner, C. S.; Basu, S.; Birch,
A. C.; Bogart, R. S.; Braun, D. C.; Cameron, R.; Duvall, T. L.;
Hanasoge, S. M.; Jackiewicz, J.; Roth, M.; Stahn, T.; Thompson, M. J.;
Zharkov, S.
Bibcode: 2009odsm.book..249G
Altcode:
Various methods of helioseismology are used to study the subsurface
properties of the sunspot in NOAA Active Region 9787. This sunspot
was chosen because it is axisymmetric, shows little evolution during
20-28 January 2002, and was observed continuously by the MDI/SOHO
instrument. AR 9787 is visible on helioseismic maps of the farside of
the Sun from 15 January, i.e. days before it crossed the East limb.
Title: New Science Opportunities Offered by MUSE
Authors: Bacon, R.; Bauer, S.; Brau-Nogué, S.; Caillier, P.; Capoani,
L.; Carollo, M.; Contini, T.; Daguisé, E.; Delabre, B.; Dreizler,
S.; Dubois, J. P.; Dupieux, M.; Dupin, J.; Emsellem, E.; Ferruit,
P.; Francois, M.; Franx, M.; Gallou, G.; Gerssen, J.; Guiderdoni,
B.; Hansali, G.; Hofmann, D.; Jarno, A.; Kelz, A.; Koehler, C.;
Kollatschny, W.; Kosmalski, J.; Laurent, F.; Lilly, S.; Lizon, J.;
Loupias, M.; Monstein, C.; Moultaka, J.; Nicklas, H.; Parés, L.;
Pasquini, L.; Pecontal, A.; Pello, R.; Petit, C.; Manescau, A.; Reiss,
R.; Remillieux, A.; Renault, E.; Roth, M.; Schaye, J.; Steinmetz,
M.; Ströbele, S.; Stuik, R.; Weilbacher, P.; Wisotzki, L.; Wozniak, H.
Bibcode: 2009ASSP....9..331B
Altcode: 2009svlt.conf..331B
The Multi Unit Spectroscopic Explorer MUSE [MUSE public web site:
http://muse.univ-lyon1.fr] is one of the second generation VLT
instruments. MUSE is a wide-field optical integral field spectrograph
operating in the visible wavelength range with improved spatial
resolution. The MUSE Consortium consists of groups at Lyon (PI
institute, CRAL), Gottingen (IAG), Potsdam (AIP), Leiden (NOVA),
Toulouse (LATT), Zurich (ETH) and ESO. The project is currently in its
final design phase. Manufacturing, assembly and integration will start
after the Final Design Review which is foreseen for late 2008. The
Preliminary acceptance in Europe is scheduled for mid 2011 and the
instrument shall be in operation at Paranal in 2012.
Title: Probing warm dense lithium by inelastic X-ray scattering
Authors: García Saiz, E.; Gregori, G.; Gericke, D. O.; Vorberger, J.;
Barbrel, B.; Clarke, R. J.; Freeman, R. R.; Glenzer, S. H.; Khattak,
F. Y.; Koenig, M.; Landen, O. L.; Neely, D.; Neumayer, P.; Notley,
M. M.; Pelka, A.; Price, D.; Roth, M.; Schollmeier, M.; Spindloe,
C.; Weber, R. L.; van Woerkom, L.; Wünsch, K.; Riley, D.
Bibcode: 2008NatPh...4..940G
Altcode:
One of the grand challenges of contemporary physics is understanding
strongly interacting quantum systems comprising such diverse examples as
ultracold atoms in traps, electrons in high-temperature superconductors
and nuclear matter. Warm dense matter, defined by temperatures of a
few electron volts and densities comparable with solids, is a complex
state of such interacting matter. Moreover, the study of warm dense
matter states has practical applications for controlled thermonuclear
fusion, where it is encountered during the implosion phase, and it also
represents laboratory analogues of astrophysical environments found in
the core of planets and the crusts of old stars. Here we demonstrate how
warm dense matter states can be diagnosed and structural properties can
be obtained by inelastic X-ray scattering measurements on a compressed
lithium sample. Combining experiments and ab initio simulations enables
us to determine its microscopic state and to evaluate more approximate
theoretical models for the ionic structure.
Title: A magnetospheric dynamo to explain quasi-stationary
acceleration of plasma in discrete auroral arcs as observed by
Cluster and DMSP spacecraft.
Authors: Maggiolo, R.; Echim, M.; Roth, M.; de Keyser, J.; Dandouras,
I.
Bibcode: 2008AGUFMSM11C..04M
Altcode:
Auroral field lines couple the ionosphere with the magnetosphere
via field-aligned currents. The nature of the generator initiating
this current system is still under debate and several mechanisms
have been proposed. In particular, we discuss a model that couples a
magnetospheric boundary and the evening polar ionosphere. The model uses
a non-linear current-voltage relationship for the upward current and
solves the current continuity equation at the top of the ionosphere. It
results in producing discrete auroral arcs, intense upward field-aligned
currents and regions of enhanced Pedersen conductance. In the dusk
sector Cluster identifies outflowing ion beams and bipolar electric
field signatures at the interface between two plasma regions with
different macroscopic properties. We estimate the orientation and
spatial scale of the plasma interface for different events as well
as the field aligned current density and parallel potential drop. In
particular we show a detailed comparison of the model results with
experimental data taken during the 28 April 2001 conjunction between
Cluster (above the acceleration region) and DMSP spacecraft (passing
trough Region 1 field-aligned currents embedding a discrete auroral
arc) discussed by Vaivads et al. (GRL, 2003). Using the discontinuity
parameters as observed in-situ by Cluster, the model fairly reproduces
the characteristics of the arc both at Cluster and DMSP altitude. This
study shows evidence of a quasi-stationary acceleration of auroral
electrons by a field aligned potential drop sustained by the convergent
electric field at a magnetospheric boundary.
Title: Comparison of geometrical mapping for ring diagram analysis
Authors: Zaatri, Amel; Corbard, Thierry; Roth, Markus; González
Hernández, Irene; von der Lühe, Oskar
Bibcode: 2008JPhCS.118a2090Z
Altcode:
Mapping the solar surface is a crucial step in any local helioseismology
technique. Because the acoustic waves propagate along great circles at
the solar surface, it has been shown that these circles need to be used
in the geometrical construction of the plane grid. We study different
types of projections based on great circles for the calculation of
sub-surface flows from ring diagram analysis of GONG data. Azimuthal
equidistant projection, transverse cylindrical projection, gnomonic
projection and stereographic projection produce almost the same velocity
fields with standard patch sizes (15°x 15°). The difference between
the four projections is more noticeable when larger patches (30° x
30°) are used.
Title: HELAS: local helioseismology data website
Authors: Schunker, Hannah; Gizon, Laurent; Roth, Markus
Bibcode: 2008JPhCS.118a2087S
Altcode: 2008arXiv0810.3414S
The Local Helioseismology Network Activity is part of the
European Helio-and Asteroseismology Network (HELAS). One
aspect of the network activity is to collate multipurpose
data sets and make them available to the community for local
helioseismic analysis. The first stage of the project is underway
whereby high quality and useful data sets have been selected and
acquired. The HELAS Local Helioseismology Network Activity website at http://www.mps.mpg.de/projects/seismo/NA4/
provides this data ready to download. Furthermore, the data is
supplemented with relevant documentation necessary for further analysis,
including details about the data reduction process that has already been
applied. The data primarily consists of Doppler velocity observations
but also includes observations of the line-of-sight magnetic field,
vector magnetic field measurements, intensity and travel time maps. The
website will be continuously updated with data thereby providing
convenient access to comprehensive data sets appropriate for use in
local helioseismology.
Title: Cross-spectral analysis of solar oscillation time series
Authors: Schad, Ariane; Roth, Markus; Schelter, Björn; von der Lühe,
Oskar; Timmer, Jens
Bibcode: 2008JPhCS.118a2091S
Altcode:
Spatial leakage is an unavoidable artifact in the extraction of solar
oscillation modes by spheric harmonic decomposition from the wavefield
observed on the solar surface. The determination of solar frequencies by
spectral analysis is therefore greatly affected by spatial leakage. Here
we show in which way spatial leakage also influences the cross-spectra
between different solar oscillation modes. Simulations show that
spatial leakage induces significant coherences between oscillations
of degree I and I + 2 with low azimuthal order m.
Title: Calculation of Spectral Darkening and Visibility Functions
for Solar Oscillations
Authors: Nutto, C.; Roth, M.; Zhugzhda, Y.; Bruls, J.; von der
Lühe, O.
Bibcode: 2008SoPh..251..179N
Altcode: 2008SoPh..tmp...63N; 2008arXiv0803.1228N
Calculations of spectral darkening and visibility functions for
the brightness oscillations of the Sun resulting from global solar
oscillations are presented. This has been done for a broad range of
the visible and infrared continuum spectrum. The procedure for the
calculations of these functions includes the numerical computation of
depth-dependent derivatives of the opacity caused by p modes in the
photosphere. A radiative-transport code was used for this purpose to
get the disturbances of the opacities from temperature and density
fluctuations. The visibility and darkening functions are obtained
for adiabatic oscillations under the assumption that the temperature
disturbances are proportional to the undisturbed temperature of the
photosphere. The latter assumption is the only way to explore any
opacity effects since the eigenfunctions of p-mode oscillations have not
been obtained so far. This investigation reveals that opacity effects
have to be taken into account because they dominate the violet and
infrared part of the spectrum. Because of this dominance, the visibility
functions are negative for those parts of the spectrum. Furthermore,
the darkening functions show a wavelength-dependent change of sign
for some wavelengths owing to these opacity effects. However, the
visibility and darkening functions under the assumptions used contradict
the observations of global p-mode oscillations, but it is beyond doubt
that the opacity effects influence the brightness fluctuations of the
Sun resulting from global oscillations.
Title: Analysis of Long Solar Oscillation Time Series
Authors: Schad, A.; Roth, M.; Timmer, J.
Bibcode: 2008ESPM...12..2.2S
Altcode:
The observations of global solar oscillations by the SOHO-MDI and the
GONG instruments cover more than 10 years. Thus, long time series of
observations are now available which should afford the investigation
of physical processes in the solar interior, e.g. deep flows, that
have small effects on solar oscillations. We analyze and discuss the
sensitivity of modern approaches of time series analysis to detect
such effects from long solar oscillation time series.
Title: Meridional Flow Measurements: Comparisons Between Ring Diagram
Analysis and Fourier-Hankel Analysis
Authors: Zaatri, A.; Roth, M.
Bibcode: 2008ESPM...122.119Z
Altcode:
The meridional circulation is a weak flow with amplitude in the order
of 10 m/s on the solar surface. As this flow could be responsible
for the transport of magnetic flux during the solar cycle it
has become a crucial ingredient in some dynamo models. However,
only less is known about the overall structure of the meridional
circulation. Helioseismology is able to provide information on
the structure of this flow in the solar interior. One widely used
helioseismic technique for measuring frequency shifts due to horizontal
flows in the subsurface layers of the sun is the ring diagram analyis
(Corbard et al. 2003). It is based on the analysis of frequency shifts
in the solar oscillation power spectrum as a function of the orientation
of the wave vector. This then allows drawing conclusions on the strength
of meridional flow, too. Ring diagram analysis is currently limited
to the analysis of the wave field in only a small region on the solar
surface. Consequently, information on the solar interior can only be
inferred down to a depth of about 16 Mm. Another helioseismology method
that promises to estimate the meridional flow strength down to greater
depths is the Fourier-Hankel analysis (Krieger et al. 2007). This
technique is based on a decomposition of the wave field in poleward
and equatorward propagating waves. A possible frequency shift between
them is then due to the meridional flow. We have been motivated for
carrying out a comparative study between the two techniques to measure
the meridional flow. We investigate the degree of coherence between the
two methods by analyzing the same data sets recorded by the SOHO-MDI
and GONG instruments.
Title: Meridional Circulation and Global Solar Oscillations
Authors: Roth, M.; Stix, M.
Bibcode: 2008SoPh..251...77R
Altcode: 2007arXiv0710.1773R; 2008SoPh..tmp..130R
We investigate the influence of large-scale meridional circulation on
solar p modes by quasi-degenerate perturbation theory, as proposed by
Lavely and Ritzwoller (Roy. Soc. Lond. Phil. Trans. Ser. A339, 431,
1992). As an input flow we use various models of stationary meridional
circulation obeying the continuity equation. This flow perturbs the
eigenmodes of an equilibrium model of the Sun. We derive the signatures
of the meridional circulation in the frequency multiplets of solar
p modes. In most cases the meridional circulation leads to negative
average frequency shifts of the multiplets. Further possibly observable
effects are briefly discussed.
Title: Local Helioseismology with GFPI at the Vacuum Tower Telescope,
Tenerife
Authors: Staiger, J.; Roth, M.; Wöhl, H.; Schleicher, H.; Puschmann,
K.
Bibcode: 2008ESPM...12..2.3S
Altcode:
Local Helioseimology has recently become an important tool to
investigate the Solar Interior in the vicinity of localized
phenomena like sunspots. It possibly holds the promise to give
informations about subsurface magnetic fields and material flows. We
are currently modifying the GFPI Instrument at the VTT which will
also be a First Light Instrument at GREGOR Telescope to the needs of
ground-based helioseismologic observations (GFPI: Göttingen Fabry
Perot Interferomer). The upgrade consists of a CCD-camera with a
larger Field-of-View (100"-by-100"), a modified Interfacing Hardware and
dedicated Control- and Recording-Software. Direct Interfacing to the
VTT's telescope control system allows for mosaic type patching of the
observations field. Cadence times of below 1 Minute for a 300"-by-300"
field at the telescope's resolution limit of 0.2" are possible. Data
are stored to USB-based external harddisks. An of-the-shelf beamer
allows for optical adjustments with an artificial light source. Available Preprocessing Tools allow to immediately visualize the
quality of the observational data. This includes a prelimary Ringdiagram
Analysis. Future Online Preprocessing Capabilities are to further
reduce the achievable cycle times. We will present some details
of the instrumental setup and some prelimiary observational results.
Title: Velocity Pattern Evolution Within the Photosphere
Authors: Nesis, A.; Hammer, R.; Schleicher, H.; Roth, M.
Bibcode: 2008ESPM...12.2.34N
Altcode:
The solar photosphere is the dynamical interface between the convection
zone and the chromosphere. It is compressible, convectively stable,
and affected by the overshooting granular flow. The photospheric
dynamics must thus be investigated as the continuation of the
granular dynamics as it spills over into the stable layers. We
investigate empirically the non-oscillatory small-scale velocity
field of the photosphere. We are particularly interested in the
temporal and height variations of the dynamics and its topological
behavior, i.e. in the evolution of velocity patterns in comparison
to the granular intensity patterns. Our analysis is based on
time series of 2D spectra taken with the triple etalon spectrograph
TESOS at the VTT on Tenerife. Oscillations were filtered out in
the Fourier domain. In a 2D time-series analysis, power spectra
demonstrate the rapid decay of the vertical overshoot velocities
with height by a factor 2 within less than 300 km above the surface,
thus implying a decay of the associated kinetic energy flux density
by nearly two orders of magnitude over the same height interval. As
expected, this decay of the energy flux is accompanied by a change of
the scales in the wavenumber domain. 2D coherence maps quantify the
drastic change of the pattern of the velocity field with height: While
the continuum layers are still governed by the typical granular-like
structuring with small-scale isotropy, the higher layers show elongated
patterns of upflow and downflow regions with short fragmentation and
reorganization time scales. According to a cross-correlation analysis
the extension of the granular upflows into the upper photosphere is a
strongly local process, suggesting a burst-like nature of the granular
velocity. Over the scale of the field of view, the velocity
field loses its horizontal isotropy with height. This suggests the
action of a structural instability of the deeper layers. It is an open
question which dynamical processes in the overshoot layers cause these
effects. The fragmentation and immediate reorganization of the velocity
field of the upper photosphere merit further study.
Title: Meridional Circulation and Global Solar Oscillations
Authors: Roth, M.; Stix, M.
Bibcode: 2008ESPM...12..3.1R
Altcode:
We investigate the influence of large-scale meridional circulation on
solar p-modes by quasi-degenerate perturbation theory, as proposed by
Lavely & Ritzwoller, 1992 (Roy. Soc. Lon. Phil. Trans. Ser. A, 339,
431). As an input flow we use various models of stationary meridional
circulation obeying the continuity equation. This flow perturbs the
eigenmodes of an equilibrium model of the Sun. We derive the signatures
of the meridional circulation in the frequency multiplets of solar
p modes. In most cases the meridional circulation leads to negative
average frequency shifts of the multiplets. Further possibly observable
effects are briefly discussed.
Title: FOREWORD: HELAS II International Conference
Authors: Gizon, Laurent; Roth, Markus
Bibcode: 2008JPhCS.118a1001G
Altcode:
Volume 118 (2008) of Journal of Physics: Conference Series provides
a written record of the talks and posters presented at the HELAS II
International Conference `Helioseismology, Asteroseismology and MHD
Connections'. The conference was held during the week 20-24 August 2007
in Göttingen, Germany, jointly hosted by the Max Planck Institute for
Solar System Research and the Faculty of Physics of the University
of Göttingen. A total of 140 scientists from all over the world
attended. The Scientific Organizing Committee consisted of Conny
Aerts, Annie Baglin, Jørgen Christensen-Dalsgaard, Thierry Corbard,
Jadwiga Daszyńska-Daszkiewicz, Stefan Dreizler, Yvonne Elsworth,
Laurent Gizon (Chairman), Wolfgang Glatzel, Frank Hill, Donald
Kurtz, Oskar von der Lühe, Maria Pia Di Mauro, Mário Monteiro,
Pere Pallé, Markus Roth, Philip Scherrer, Manfred Schüssler,
and Michael Thompson. HELAS stands for the European Helio- and
Asteroseismology Network, a Coordination Action supported by the sixth
Framework Programme of the European Union. It aims to bring together
researchers in the fields of solar and stellar oscillations. This
volume consists of 91 articles organized into sections that reflect the
scientific programme of the conference: 012001-07 Wave diagnostics
in physics, geophysics and astrophysics 012008-09 Perspectives on helio-
and asteroseismology 012010-17 Asteroseismology: Observations 012018-25
Asteroseismology: Theory 012026-32 Global helioseismology and solar
models 012033-38 Local helioseismology and magnetic activity 012039-44
Future observational projects in helio- and asteroseismology 012045-91
Poster papers. The overwhelming majority of papers discuss the
seismology of the Sun and stars. Papers in the first section provide a
broader perspective on wave phenomena and techniques for probing other
physical systems, from living beings to the universe as a whole. We
were extremely fortunate to have particularly distinguished experts
to cover these topics. Also available in the online edition are
(i) an interactive conference picture, (ii) the abstract book, and
(iii) material on the special session `Waves, Waves and Waves'. Additional articles related to both the HELAS II and the SOHO
19/GONG 2007 conferences can be found in a topical issue of Solar
Physics, volume 251, nos 1-2. Financial support was provided by
the HELAS Network, the Max Planck Institute for Solar System Research
(through Ulrich Christensen and Sami Solanki) and the University of
Göttingen (through Stefan Dreizler). We thank the local organizers,
and in particular Sabine Deutsch, for their outstanding efforts
in making the conference a success. We are also grateful to Graham
Douglas and Jacky Mucklow of IoP Publishing for their help in the
production of this volume. Laurent Gizon and Markus Roth Editors
Katlenburg-Lindau, Germany
Title: Nuevas observaciones del joven y aislado cúmulo embebido GM 24
Authors: Tapia, M.; Rodriguez, L. F.; Roth, M.; Persi, P.; Gómez, M.
Bibcode: 2008iac..talk...70T
Altcode: 2008iac..talk...11T
No abstract at ADS
Title: Trigger Strategy for Radio Detection in Atmospheric Air
Showers with LOPESST AR
Authors: Asch, T.; Apel, W. D.; Arteaga, J. C.; Auffenberg, J.; Badea,
F.; Bähren, L.; Bekk, K.; Bertaina, M.; Biermann, P. L.; Blümer,
J.; Bozdog, H.; Brancus, I. M.; Brüggemann, M.; Buchholz, P.;
Buitink, S.; Butcher, H.; Chiavassa, A.; Cossavella, F.; Daumiller,
K.; de Souza, V.; Di Pierro, F.; Doll, P.; Engel, R.; Falcke, H.;
Gemmeke, H.; Ghia, P. L.; Glasstetter, R.; Grupen, C.; Haungs, A.;
Heck, D.; Hörandel, J. R.; Horneffer, A.; Huege, T.; Isar, P. G.;
Kampert, K. -H.; Kickelbick, D.; Kolotaev, Y.; Krömer, O.; Kuijpers,
Lafebre, S.; Luczak, P.; Mathes, H. J.; Mayer, H. J.; Meurer, C.;
Milke, J.; Mitrica, B.; Morello, C.; Navarra, G.; Nehls, S.; Nigl, A.;
Oehlschläger, J.; Ostapchenko, S.; Over, S.; Petcu, M.; Petrovic,
J.; Pierog, T.; Plewnia, S.; Rautenberg, J.; Rebel, H.; Roth, M.;
Schieler, H.; Sima, O.; Singh, K.; Stümpert, M.; Toma, G.; Trinchero,
G. C.; Ulrich, H.; van Buren, J.; Walkowiak, W.; Weindl, A.; Wochele,
J.; Zabierowski, J.; Zensus, J. A.
Bibcode: 2008ICRC....5.1081A
Altcode: 2008ICRC...30e1081A
In the framework of LOPES (LOFAR PrototypE Station), a Self-Triggered
Array of Radio detectors (STAR) is developed. The challenge of
LOPESSTAR is to provide an independent self-trigger on radio
emission of extensive air showers with primary energy above approximate
5*1017 eV. Measurements are done both with an external and
self-trigger in radio loud and quiet areas. Based on these data the
self-trigger is optimised and higher level triggers are developed,
as well as algorithms for reconstruction of shower observables. The
methods and first results from LOPESSTAR are described.
Title: MUSE: A Second-Generation Integral-Field Spectrograph for
the VLT
Authors: McDermid, R. M.; Bacon, R.; Bauer, S.; Boehm, P.; Boudon,
D.; Brau-Nogué, S.; Caillier, P.; Capoani, L.; Carollo, C. M.;
Champavert, N.; Contini, T.; Daguisé, E.; Delabre, B.; Devriendt,
J.; Dreizler, S.; Dubois, J.; Dupieux, M.; Dupin, J. P.; Emsellem, E.;
Ferruit, P.; Franx, M.; Gallou, G.; Gerssen, J.; Guiderdoni, B.; Hahn,
T.; Hofmann, D.; Jarno, A.; Kelz, A.; Koehler, C.; Kollatschny, W.;
Kosmalski, J.; Laurent, F.; Lilly, S. J.; Lizon, J. L.; Loupias, M.;
Manescau, A.; Monstein, C.; Nicklas, H.; Parès, L.; Pasquini, L.;
Pécontal-Rousset, A.; Pécontal, E.; Pello, R.; Petit, C.; Picat,
J. -P.; Popow, E.; Quirrenbach, A.; Reiss, R.; Renault, E.; Roth,
M.; Schaye, J.; Soucail, G.; Steinmetz, M.; Stroebele, S.; Stuik,
R.; Weilbacher, P.; Wisotzki, L.; Wozniak, H.; de Zeeuw, P. T.
Bibcode: 2008eic..work..325M
Altcode:
The Multi Unit Spectroscopic Explorer (MUSE) is a second-generation
instrument in development for the Very Large Telescope (VLT) of
the European Southern Observatory (ESO), due to begin operation in
2011/12. MUSE will be an extremely powerful integral-field spectrograph
fed by a new multiple-laser adaptive optics system on the VLT. In its
usual operating mode, MUSE will, in a single observation, produce
a 3-dimensional data cube consisting of 90,000 R 3000 spectra,
each covering a full spectral octave (480-930 nm), and fully
sampling a contiguous 1×1 arcmin2 field with 0.2×0.2
arcsec2 apertures. A high-resolution mode will increase
the spatial sampling to 0.025 arcsec per pixel. MUSE is built around
a novel arrangement of 24 identical spectrographs (each comparable
to a 1st generation VLT instrument), which are fed by a set of 24
precision image slicers. MUSE is designed for stability, with only 2
modes, and virtually no moving parts, allowing very long exposures to
be accumulated. Together with high throughput, this ensures that MUSE
will have extreme sensitivity for observing faint objects. We overview
the technical and scientific aspects of MUSE, highlighting the key
challenges for dealing with the unprecedented quantity and complexity
of the data, and the integration with the VLT adaptive optics facility
(AOF) - a key development on the path to extremely large telescopes
(ELTs).
Title: Shower evolution and radio emission of air showers in
thunderstorm electric fields
Authors: Buitink, S.; Apel, W. D.; Arteaga, J. C.; Asch, T.;
Auffenberg, J.; Badea, F.; Bähren, L.; Bekk, K.; Bertaina, M.;
Biermann, P. L.; Blümer, J.; Bozdog, H.; Brancus, I. M.; Brüggemann,
M.; Buchholz, P.; Butcher, H.; Chiavassa, A.; Cossavella, F.;
Daumiller, K.; de Souza, V.; Di Pierro, F.; Doll, P.; Engel, R.;
Falcke, H.; Gemmeke, H.; Ghia, P. L.; Glasstetter, R.; Grupen, C.;
Haungs, A.; Heck, D.; Hörandel, J. R.; Horneffer, A.; Huege, T.; Isar,
P. G.; Kampert, K. -H.; Kickelbick, D.; Kolotaev, Y.; Krömer, O.;
Kuijpers, J.; Lafebre, S.; Luczak, P.; Mathes, H. J.; Mayer, H. J.;
Meurer, C.; Milke, J.; Mitrica, B.; Morello, C.; Navarra, G.; Nehls,
S.; Nigl, A.; Oehlschläger, J.; Ostapchenko, S.; Over, S.; Petcu,
M.; Petrovic, J.; Pierog, T.; Plewnia, S.; Rautenberg, J.; Rebel, H.;
Roth, M.; Schieler, H.; Sima, O.; Singh, K.; Stümpert, M.; Toma, G.;
Trinchero, G. C.; Ulrich, H.; van Buren, J.; Walkowiak, W.; Weindl,
Wochele, J.; Zabierowski, J.; Zensus, J. A.
Bibcode: 2008ICRC....4..161B
Altcode: 2008ICRC...30d.161B
The radio emission from cosmic ray air showers consists in large part
of geosynchrotron radiation. Since the radiation mechanism is based
on particle acceleration, atmospheric electric fields may play an
important role. LOPES results show that electric fields under fair
weather conditions do not alter the radio emission considerably,
but during thunderstorms strongly amplified pulses are measured. The
electric field influence on the shower development and radio emission
is simulated with a modified version of CORSIKA and with REAS2,
respectively We present results from both data analysis and simulation.
Title: MUSE Data Reduction & Analysis
Authors: Gerssen, J.; Weilbacher, P.; Boehm, P.; Roth, M.
Bibcode: 2007ASPC..376..301G
Altcode: 2007adass..16..301G
The Multi-Unit Spectroscopic Explorer (MUSE) is a second generation IFU
for the VLT. Its unique combination of a finely sampled large field
of view over nearly the full optical wavelength range results in a
large data rate. Processing the data efficiently requires a largely
automatic data reduction system. Here, we outline the requirements
for the MUSE reduction pipeline and briefly mention the data analysis
tools that we are starting to develop.
Title: D3Dnet: getting ready for MUSE, a 2nd Generation Instrument
for the VLT
Authors: Roth, M.; Weilbacher, P.; Gerssen, J.
Bibcode: 2007AN....328..633R
Altcode:
No abstract at ADS
Title: A Study of the Type Ia/IIn Supernova 2005gj from X-ray to
the Infrared: Paper I
Authors: Prieto, J. L.; Garnavich, P. M.; Phillips, M. M.; DePoy,
D. L.; Parrent, J.; Pooley, D.; Dwarkadas, V. V.; Baron, E.; Bassett,
B.; Becker, A.; Cinabro, D.; DeJongh, F.; Dilday, B.; Doi, M.; Frieman,
J. A.; Hogan, C. J.; Holtzman, J.; Jha, S.; Kessler, R.; Konishi, K.;
Lampeitl, H.; Marriner, J.; Marshall, J. L.; Miknaitis, G.; Nichol,
R. C.; Riess, A. G.; Richmond, M. W.; Romani, R.; Sako, M.; Schneider,
D. P.; Smith, M.; Takanashi, N.; Tokita, K.; van der Heyden, K.;
Yasuda, N.; Zheng, C.; Wheeler, J. C.; Barentine, J.; Dembicky, J.;
Eastman, J.; Frank, S.; Ketzeback, W.; McMillan, R. J.; Morrell, N.;
Folatelli, G.; Contreras, C.; Burns, C. R.; Freedman, W. L.; Gonzalez,
S.; Hamuy, M.; Krzeminski, W.; Madore, B. F.; Murphy, D.; Persson,
S. E.; Roth, M.; Suntzeff, N. B.
Bibcode: 2007arXiv0706.4088P
Altcode:
We present extensive ugrizYHJK photometry and optical spectroscopy of
SN 2005gj obtained by the SDSS-II and CSP Supernova Projects, which
give excellent coverage during the first 150 days after the time of
explosion. These data show that SN 2005gj is the second clear case,
after SN 2002ic, of a thermonuclear explosion in a dense circumstellar
environment. Both the presence of singly and doubly ionized iron-peak
elements (FeIII and weak SII, SiII) near maximum light as well as
the spectral evolution show that SN 2002ic-like events are Type Ia
explosions. Independent evidence comes from the exponential decay in
luminosity of SN 2005gj, pointing to an exponential density distribution
of the ejecta. The interaction of the supernova ejecta with the dense
circumstellar medium is stronger than in SN 2002ic: (1) the supernova
lines are weaker; (2) the Balmer emission lines are more luminous; and
(3) the bolometric luminosity is higher close to maximum light. The
velocity evolution of the Halpha components suggest that the CSM around
SN 2005gj is clumpy and it has a flatter density distribution compared
with the steady wind solution, in agreement with SN 2002ic. An early
X-ray observation with Chandra gives an upper-limit on the mass loss
rate from the companion of < 2x10^{-4} Msun/yr.
Title: The Network Activities in HELAS
Authors: Roth, M.
Bibcode: 2007CoAst.150..287R
Altcode:
The Helio- and Asteroseismology Network (HELAS) is a Coordinated
Action funded by the FP6-Infrastructure-Programme of the European
Commission. The objective of HELAS is to co-ordinate European activities
in helio- and asteroseismology. In order to achieve this objective
HELAS runs six network activities. I describe these in this short
contribution, with a special focus on the asteroseismology network
activity.
Title: A Spectacular Radio Flare from XRF 050416a at 40 Days and
Implications for the Nature of X-Ray Flashes
Authors: Soderberg, A. M.; Nakar, E.; Cenko, S. B.; Cameron, P. B.;
Frail, D. A.; Kulkarni, S. R.; Fox, D. B.; Berger, E.; Gal-Yam, A.;
Moon, D. -S.; Price, P. A.; Anderson, G.; Schmidt, B. P.; Salvo, M.;
Rich, J.; Rau, A.; Ofek, E. O.; Chevalier, R. A.; Hamuy, M.; Harrison,
F. A.; Kumar, P.; MacFadyen, A.; McCarthy, P. J.; Park, H. S.;
Peterson, B. A.; Phillips, M. M.; Rauch, M.; Roth, M.; Shectman, S.
Bibcode: 2007ApJ...661..982S
Altcode: 2006astro.ph..7511S
We present detailed optical, near-infrared, and radio observations of
the X-ray flash XRF 050416a obtained with Palomar and Siding Springs
Observatories, as well as the HST and VLA, placing this event among
the best-studied X-ray flashes to date. In addition, we present an
optical spectrum from Keck LRIS from which we measure the redshift of
the burst, z=0.6528. At this redshift the isotropic-equivalent prompt
energy release was about 1051 ergs, and using a standard
afterglow synchrotron model, we find that the blast wave kinetic
energy is a factor of 10 larger, EK,iso~1052
ergs. The lack of an observed jet break to t~20 days indicates that
the opening angle is θj>~7deg and the
total beaming-corrected relativistic energy is >~1050
ergs. We further show that the burst produced a strong radio flare
at t~40 days accompanied by an observed flattening in the X-ray
band, which we attribute to an abrupt circumburst density jump or
an episode of energy injection (from either a refreshed shock or
off-axis ejecta). Late-time observations with HST show evidence for an
associated supernova with peak optical luminosity roughly comparable to
that of SN 1998bw. Next, we show that the host galaxy of XRF 050416a
is actively forming stars at a rate of at least 2 Msolar
yr-1 with a luminosity of LB~0.5L*
and metallicity of Z~0.2-0.8 Zsolar. Finally, we discuss
the nature of XRF 050416a in the context of short-hard GRBs and under
the framework of off-axis and dirty fireball models for X-ray flashes.
Title: The near-infrared counterpart to XTE J1856+053
Authors: Torres, M. A. P.; Steeghs, D.; Jonker, P. G.; Morrell, N.;
Roth, M.; Kerber, F.
Bibcode: 2007ATel.1072....1T
Altcode:
We report the detection of the near-infrared counterpart to the X-
ray transient and black hole candidate XTE J1856+053 (Marshall et
al. 1996, IAUC #6504; Barret et al. 1996, IAUC #6519). This finding
is based on follow-up observations of the currently ongoing outburst
(Levine et al. 2007; ATel #1024) with the 6.5m Magellan Baade telescope
at Las Campanas observatory.
Title: Estimating the solar meridional circulation by normal mode
decomposition
Authors: Krieger, L.; Roth, M.; von der Lühe, O.
Bibcode: 2007AN....328..252K
Altcode: 2008arXiv0811.0693K
The objective of this article is to use Fourier-Hankel decomposition as
suggested earlier by Braun & Fan (1998) to estimate the integrated
horizontal meridional flow velocity as a function of mode penetration
depth, and to find ways of potentially improve this technique. We use
a time series of 43200 (30 days) consecutive full-disk Dopplergrams
obtained by the MDI (Michelson Doppler Imager) instrument aboard the
SOHO (Solar Heliospheric Observatory) spacecraft in April 1999. We
find averaged meridional flow estimates of 15 m/s for modes with a
penetration depth in the upper 20 Mm of the solar convection zone. This
reproduces the results of the earlier investigations. Moreover we
conclude that this method has the potential to become a new technique
to measure the meridional circulation in the deep convection zone,
if some improvements will be applied.
Title: Measuring helioseismic travel times
Authors: Roth, M.; Gizon, L.; Beck, J. G.
Bibcode: 2007AN....328..215R
Altcode:
In time-distance helioseismology wave travel times are measured
from the cross-correlation between Doppler velocities recorded at
any two locations on the solar surface. We compare two different
methods to extract the travel times from the noisy cross-correlation
functions. The first method consists of fitting a 5-parameter analytic
function to the cross-correlation to obtain the phase travel time. The
second method consists of linearizing the distance between the observed
cross-correlation and a sliding reference cross-correlation (the only
parameter is the travel time). We find that the one-parameter fits
are more robust with respect to noise. Using SOHO data from the MDI
Structure Program for the years 1996-2003, we study in detail the
statistical properties of the noise associated with the travel-time
measurements for the two different fitting methods.
Title: The NIR counterpart to IGR J17497-2821
Authors: Torres, M. A. P.; Steeghs, D.; Jonker, P. G.; Morrell, N.;
Roth, M.; Freedman, W. L.
Bibcode: 2007ATel.1002....1T
Altcode:
We report follow-up observations confirming the near-infrared (NIR)
counterpart to the X-ray transient and suggested black hole candidate
IGR J17497-2821 (Soldi et al., ATel #885). A Ks=15.9 mag candidate was
suggested in Torres et al. (ATel #909) on the basis of its coincidence
with the Chandra localization for the X-ray source (Paizis et al. ATel
#907; astro-ph/0611344). The candidate appeared blended with a brighter
nearby NIR source to the east which partially overlaps the 0.6 arscec
Chandra error circle.
Title: Future missions for helioseismology
Authors: Roth, M.
Bibcode: 2007msfa.conf...85R
Altcode:
In this paper I provide basic information on the scientific objectives
of upcoming helioseismology missions. The launch of NASA's Solar
Dynamics Observatory (SDO) in 2008 is an important opportunity for
helioseismology. SDO will carry the Helioseismic and Magnetic Imager
(HMI), which will have a 1" resolution over the whole visible solar
disc and is especially designed for local helioseismology. ESA's Solar
Orbiter, to be launched ten years from now, will allow the study of the
subsurface structure and dynamics of the Sun at high latitudes. Just
recently, Hinode (Solar-B) was launched. It is designed to deliver
Dopplergrams at 0.3" resolution. Ground-based observations are also
expected to complement space projects.
Title: GRB 071227: magellan redshift confirmation.
Authors: Berger, E.; Morrell, N.; Roth, M.
Bibcode: 2007GCN..7154....1B
Altcode:
No abstract at ADS
Title: Helioseismology at MPS
Authors: Gizon, L.; Cameron, R.; Jackiewicz, J.; Roth, M.; Schunker,
H.; Stahn, T.
Bibcode: 2007msfa.conf...89G
Altcode:
Research in solar and stellar seismology at the Max Planck Institute
for Solar System Research (MPS) is supported by the Junior Research
Group "Helio- and Asteroseismology" of the Max Planck Society since
September 2005. A presentation of the current topics of research is
given, with particular emphasis on local helioseismology.
Title: GRB 071227: magellan observations.
Authors: Berger, E.; Morrell, N.; Roth, M.
Bibcode: 2007GCN..7151....1B
Altcode:
No abstract at ADS
Title: Integral Field Spectroscopy Survey of Classical LBV Stars
in M33
Authors: Sholukhova, O.; Abolmasov, P.; Fabrika, S.; Afanasiev, V.;
Roth, M.
Bibcode: 2007spts.conf..355S
Altcode:
Five well-known LBV stars in M33 were observed with the Multi-Pupil
Fiber Spectrograph (MPFS) on the 6-m Russian telescope. We observed
LBVs varA, var B, varC, var 2 and var 83. In three of them, var 2,
var 83, varB, largescale nebulae were found with sizes from 15 pc
and larger. The nebula shapes are complex, like one-side tails or
conical nebulae. They all are related to their LBV stars. In var 2
and var 83 stars we found radial velocity gradients 15-30 km/s across
their nebulae. The stars varA and varC do not show extended nebulae,
but nebular lines are certainty present in their spectra.
Title: European helio- and asteroseismology network HELAS
Authors: Roth, M.; Luhe, O. v. d.; Palle, P.; Thompson, M. J.;
Christensen-Dalsgaard, J.; Monteiro, M. J. P. F. G.; Gizon, L.;
Di Mauro, M. P.; Aerts, C.; Daszynska-Daszkiewicz, J.; Corbard, T.
Bibcode: 2006ESASP.624E.130R
Altcode: 2006soho...18E.130R
The Helio- and Asteroseismology Network (HELAS) is a Coordinated
Action funded by the FP6-Infrastructure-Programme of the European
Commission. Currently, HELAS consists of ten members. The objective
of HELAS is to co-ordinate European activities in helio- and
asteroseismology. HELAS will transfer knowledge and data analysis
techniques, and will prepare the European research community for
important missions in the immediate future.
Title: Asteroseismology of K giants
Authors: di Mauro, M. P.; Cardini, D.; D'Antona, F.; Weiss, A.;
Döllinger, M. P.; Pasquini, L.; Girardi, L.; Hatzes, A.; von der
Lühe, O.; de Medeiros, J. R.; Roth, M.; Setaiwan, J.; da Silva, L.
Bibcode: 2006ESASP.624E.118D
Altcode: 2006soho...18E.118D
No abstract at ADS
Title: Sensitivity kernels for helioseismic travel times in spherical
geometry preliminary results
Authors: Roth, M.; Gizon, L.; Birch, A. C.
Bibcode: 2006ESASP.624E..43R
Altcode: 2006soho...18E..43R
No abstract at ADS
Title: Computational Acoustics in Spherical Geometry: Steps toward
Validating Helioseismology
Authors: Hanasoge, S. M.; Larsen, R. M.; Duvall, T. L., Jr.; De Rosa,
M. L.; Hurlburt, N. E.; Schou, J.; Roth, M.; Christensen-Dalsgaard,
J.; Lele, S. K.
Bibcode: 2006ApJ...648.1268H
Altcode:
Throughout the past decade, detailed helioseismic analyses of
observations of solar surface oscillations have led to advances in our
knowledge of the structure and dynamics of the solar interior. Such
analyses involve the decomposition of time series of the observed
surface oscillation pattern into its constituent wave modes, followed
by inversion procedures that yield inferences of properties of the
solar interior. While this inverse problem has been a major focus in
recent years, the corresponding forward problem has received much less
attention. We aim to rectify this situation by taking the first steps
toward validating and determining the efficacy of the helioseismic
measurement procedure. The goal of this effort is to design a means
to perform differential studies of various effects such as flows and
thermal perturbations on helioseismic observables such as resonant
frequencies, travel-time shifts, etc. Here we describe our first
efforts to simulate wave propagation within a spherical shell,
which extends from 0.2 to about 1.0004 Rsolar (where
Rsolar is the radius of the Sun) and which possesses a
solar-like stratification. We consider a model containing no flows
that will serve as a reference model for later studies. We discuss the
computational procedure, some difficulties encountered in a simulation
of this kind, and the means to overcome them. We also present techniques
used to validate the simulation.
Title: Helas-European Helio- and Asteroseismology Network
Authors: Roth, M.; Lühe, O. v. d.; Pallé, P.; Thompson, M.;
Christensen-Dalsgaard, J.; Monteiro, M. J. P. F. G; Gizon, L.; Di
Mauro, M. P.; Aerts, C.; Daszynska-Daszkiewicz, J.; Corbard, T.
Bibcode: 2006ESASP.617E.157R
Altcode: 2006soho...17E.157R
No abstract at ADS
Title: Dynamics of the solar granulation. IX. A global approach
Authors: Nesis, A.; Hammer, R.; Roth, M.; Schleicher, H.
Bibcode: 2006A&A...451.1081N
Altcode:
Based on a series of spectrograms taken with the German Vacuum Tower
Telescope (VTT) at the Observatorio del Teide (Tenerife), we study the
temporal evolution of granular dynamics and energy transport in the
photospheric layers. We consider the ensemble of the granules cut by
the spectrograph slit, modulated by wave motion, as a complex system. We
describe this ensemble by the rms of the fluctuations of the observables
along the slit: continuum intensity I, gas velocity v measured from
line center Doppler shifts with respect to the mean profile, and line
width w. The history of the rms of the observables v and w reflects the
dynamical change of the system over the 20 min observation time. We find
a burst-like change for both observables. However, the cross-correlation
between I and v remains virtually constant, with the exception of two
gaps. Using six lines of different strength we measure the rms of v in
the deep photospheric layers. On the basis of this v variation we derive
an upper limit of the kinetic energy flux as a function of height in the
photosphere for different times during the observation. The shape of the
variation with height is constant over time. A limit for the convective
enthalpy flux is calculated using the temperature variations of our
earlier models. Its shape remains the same over time. Taken together,
these results quantify the different roles that the lower and higher
photospheric layers play in the energetics of convective overshoot.
Title: Probing unexplored territories with MUSE: a second generation
instrument for the VLT
Authors: Bacon, R.; Bauer, S.; Boehm, P.; Boudon, D.; Brau-Nogué, S.;
Caillier, P.; Capoani, L.; Carollo, C. M.; Champavert, N.; Contini,
T.; Daguisé, E.; Dallé, D.; Delabre, B.; Devriendt, J.; Dreizler,
S.; Dubois, J.; Dupieux, M.; Dupin, J. P.; Emsellem, E.; Ferruit, P.;
Franx, M.; Gallou, G.; Gerssen, J.; Guiderdoni, B.; Hahn, T.; Hofmann,
D.; Jarno, A.; Kelz, A.; Koehler, C.; Kollatschny, W.; Kosmalski,
J.; Laurent, F.; Lilly, S. J.; Lizon, J.; Loupias, M.; Lynn, S.;
Manescau, A.; McDermid, R. M.; Monstein, C.; Nicklas, H.; Parès, L.;
Pasquini, L.; Pécontal-Rousset, A.; Pécontal, E.; Pello, R.; Petit,
C.; Picat, J. -P.; Popow, E.; Quirrenbach, A.; Reiss, R.; Renault,
E.; Roth, M.; Schaye, J.; Soucail, G.; Steinmetz, M.; Stroebele, S.;
Stuik, R.; Weilbacher, P.; Wozniak, H.; de Zeeuw, P. T.
Bibcode: 2006SPIE.6269E..0JB
Altcode: 2006astro.ph..6329B; 2006SPIE.6269E..17B
The Multi Unit Spectroscopic Explorer (MUSE) is a second-generation
VLT panoramic integral-field spectrograph under preliminary design
study. MUSE has a field of 1x1 arcmin2 sampled at 0.2x0.2
arcsec2 and is assisted by the VLT ground layer adaptive
optics ESO facility using four laser guide stars. The simultaneous
spectral range is 0.465-0.93 μm, at a resolution of R~3000. MUSE
couples the discovery potential of a large imaging device to the
measuring capabilities of a high-quality spectrograph, while taking
advantage of the increased spatial resolution provided by adaptive
optics. This makes MUSE a unique and tremendously powerful instrument
for discovering and characterizing objects that lie beyond the reach
of even the deepest imaging surveys. MUSE has also a high spatial
resolution mode with 7.5x7.5 arcsec2 field of view sampled at
25 milli-arcsec. In this mode MUSE should be able to obtain diffraction
limited data-cubes in the 0.6-0.93 μm wavelength range. Although the
MUSE design has been optimized for the study of galaxy formation and
evolution, it has a wide range of possible applications; e.g. monitoring
of outer planets atmosphere, environment of young stellar objects,
super massive black holes and active nuclei in nearby galaxies or
massive spectroscopic surveys of stellar fields in the Milky Way and
nearby galaxies.
Title: Supernovae 2006bh and 2006bn
Authors: Morrell, N.; Folatelli, G.; Roth, M.; Gonzalez, S.
Bibcode: 2006CBET..492....1M
Altcode:
N. Morrell, G. Folatelli, M. Roth, and S. Gonzalez, on behalf of the
Carnegie Supernova Project, report that spectroscopic observations
(range 380-920 nm) of SN 2006bh (cf. IAUC 8697, CBET 457) obtained on
Apr. 24.40 UT and of SN 2006bn (cf. IAUC 8699, CBET 467) on Apr. 23.29
and 26.22, with the WFCCD spectrograph attached to the 2.5-m du Pont
telescope at Las Campanas Observatory, reveal that both are type-Ia
supernovae. A spectral-feature age (Riess et al. 1997, A.J. 114, 722)
of 14 days past maximum was derived for SN 2006bh. The spectrum of SN
2006bn resembles those of SN 1999bv (Matheson et al. 2001, A.J. 121,
1648) and SN 1996X at 57 days past maximum light, as determined by
means of the 'superfit' supernova-spectrum-comparison code (Howell et
al. 2005, Ap.J. 634, 1190). SN 2006bn is thus classified as a type-Ia
supernova, 2 or 3 months past maximum.
Title: Multi-periodic oscillations of HD 32887 and HD 81797.
Authors: Setiawan, J.; Roth, M.; Weise, P.; Dölinger, M. P.
Bibcode: 2006MmSAI..77..510S
Altcode: 2005astro.ph..5184S
In this paper we present two evolved stars, HD 32887 and HD 81797,
which show multi-periodic oscillations. We observed the oscillations by
means of the precise radial velocity technique with the simultaneous
calibration method. The high-resolution spectra of each star have
been obtained with FEROS at the 2.2 m-MPG/ESO telescope in La Silla
Observatory, Chile. We found variation in the stellar radial velocities
and spectral line profiles. The periods of the oscillations are from
several hours up to few days. The sources of the short-term oscillations
of HD 32887 and HD 81797 are obviously due to stellar pulsations, which
are similar to solar-like oscillations. In particular, in HD 81797 we
found a clear correlation between the variation in the asymmetry of
the spectral line profile, measured in the bisector velocity spans,
and the radial velocity. Both stars have bisector velocity spans which
also show oscillations. The periods of the bisector oscillations are
similar to those of the radial velocity variation. The detection of
the multi-periodic oscillations in HD 32887 and HD 81797 makes these
star to be amenable targets for asteroseismology, in particular,
of stars in the red giant branch.
Title: Solar wind pressure and the position of the magnetopause:
a Cluster perspective
Authors: de Keyser, Johan; Roth, M.; Dunlop, M. W.; Rème, H.; Owen,
C. J.; Paschmann, G.
Bibcode: 2006ESASP.598E..14D
Altcode: 2006cds..sympE..14D
No abstract at ADS
Title: Why are G and K Giants Radial Velocity Variables?
Authors: Doellinger, Michaela Petronilla; Pasquini, Luca; Hatzes,
Artie Peter; Setiawan, Johny; da Silva, Licio; Renan de Medeiros,
Jose; von der Luehe, Oskar; Girardi, Leo; di Mauro, Maria Pia; Weiss,
Achim; Roth, Markus
Bibcode: 2005Msngr.122...39D
Altcode:
During the past year ESO has coordinated a number of instrument concept
studies as a complement to the OWL Observatory Design Study. Eight teams
of scientists and engineers from different institutes in Europe and
ESO have identified a variety of science programmes at the frontier of
astrophysics and developed concepts of instruments at OWL which would
be able to carry them out. This exercise has provided a first view of
the unique astronomical observations at Blue to IR wavelengths which
will become possible with a future European Extremely Large Telescope.
Title: The afterglow of GRB 050709 and the nature of the short-hard
γ-ray bursts
Authors: Fox, D. B.; Frail, D. A.; Price, P. A.; Kulkarni, S. R.;
Berger, E.; Piran, T.; Soderberg, A. M.; Cenko, S. B.; Cameron, P. B.;
Gal-Yam, A.; Kasliwal, M. M.; Moon, D. -S.; Harrison, F. A.; Nakar,
E.; Schmidt, B. P.; Penprase, B.; Chevalier, R. A.; Kumar, P.; Roth,
K.; Watson, D.; Lee, B. L.; Shectman, S.; Phillips, M. M.; Roth, M.;
McCarthy, P. J.; Rauch, M.; Cowie, L.; Peterson, B. A.; Rich, J.;
Kawai, N.; Aoki, K.; Kosugi, G.; Totani, T.; Park, H. -S.; MacFadyen,
A.; Hurley, K. C.
Bibcode: 2005Natur.437..845F
Altcode: 2005astro.ph.10110F
The final chapter in the long-standing mystery of the γ-ray bursts
(GRBs) centres on the origin of the short-hard class of bursts, which
are suspected on theoretical grounds to result from the coalescence
of neutron-star or black-hole binary systems. Numerous searches for
the afterglows of short-hard bursts have been made, galvanized by the
revolution in our understanding of long-duration GRBs that followed
the discovery in 1997 of their broadband (X-ray, optical and radio)
afterglow emission. Here we present the discovery of the X-ray afterglow
of a short-hard burst, GRB 050709, whose accurate position allows us to
associate it unambiguously with a star-forming galaxy at redshift z =
0.160, and whose optical lightcurve definitively excludes a supernova
association. Together with results from three other recent short-hard
bursts, this suggests that short-hard bursts release much less energy
than the long-duration GRBs. Models requiring young stellar populations,
such as magnetars and collapsars, are ruled out, while coalescing
degenerate binaries remain the most promising progenitor candidates.
Title: The role of sounding rocket microgravity experiments within
the German Physical Sciences Programme
Authors: Kuhl, R.; Roth, M.; Binnenbruck, H.; Dreier, W.; Forke, R.;
Preu, P.
Bibcode: 2005ESASP.590..503K
Altcode: 2005erbp.conf..503K
The German Physical Sciences Programme, managed by the German
Space Agency DLR, deals with investigations of the effects of
weightlessness ("microgravity") on physical and chemical processes and
phenomena. The research priorities concern materials design from the
melt, fluid flow dynamics, basic mechanisms of combustion processes, and
fundamental particle interactions. In retrospect, using different flight
opportunities, in total more than 600 microgravity experiments involving
German principal investigators in the field of physical sciences were
performed till now. It turns out that more than a quarter of them
flew on sounding rockets. Among the different rocket types used the
TEXUS carrier proved to be the "workhorse" of the huge majority of the
German experiments during three decades. Some characteristic examples
of facility developments and experimental results are given to highlight
the pioneering gain of knowledge using sounding rocket flights.
Title: Crowded field 3D spectroscopy of LBV candidates in M 33
Authors: Fabrika, S.; Sholukhova, O.; Becker, T.; Afanasiev, V.;
Roth, M.; Sanchez, S. F.
Bibcode: 2005A&A...437..217F
Altcode: 2005astro.ph..3586F
We present integral field spectroscopy of the LBV candidate stars B
416 and v 532 in the local group galaxy M 33. B 416 is surrounded by
an elongated ring-like nebula, which has a projected radius of 20 ×
30 pc. From the datacube we create ionization and radial velocity maps
of the nebula. The excitation of the gas decreases towards the outer
part of the ring, while the inner part of the nebula is filled with a
more excited gas. In the EW direction the ring is seen to expand with a
maximum projected velocity amplitude of about 40 km s-1. The
eastern part approaches the observer. We estimate the nebula dynamical
lifetime ∼ 8 × 105 years. It could be a residual MS
bubble, which indicates a main-sequence or pre-LBV status of the
star. We classify B 416 as an "iron star" or B[e]-supergiant. In
v 532 an elongated nebula has been marginally detected. The total
projected size of the nebula along the main axis is 30 pc, and the
total radial velocity gradient is 44 ± 11 km s-1. v 532
exhibits both strong photometric and spectral variability. At the
time of our observations it was in an intermediate brightness state
with a rich nitrogen spectrum. We classify v 532 as an LBV, showing
LBV ≤ftrightarrow Ofpe/WN transitions. We stress the importance
of integral field spectroscopy as the optimal technique for studying
nebulae and the evolution of LBV-like stars in nearby galaxies.
Title: An HST Search for Supernovae Accompanying X-Ray Flashes
Authors: Soderberg, A. M.; Kulkarni, S. R.; Fox, D. B.; Berger, E.;
Price, P. A.; Cenko, S. B.; Howell, D. A.; Gal-Yam, A.; Leonard,
D. C.; Frail, D. A.; Moon, D.; Chevalier, R. A.; Hamuy, M.; Hurley,
K. C.; Kelson, D.; Koviak, K.; Krzeminski, W.; Kumar, P.; MacFadyen,
A.; McCarthy, P. J.; Park, H. S.; Peterson, B. A.; Phillips, M. M.;
Rauch, M.; Roth, M.; Schmidt, B. P.; Shectman, S.
Bibcode: 2005ApJ...627..877S
Altcode: 2005astro.ph..2553S
We present the results from a Hubble Space Telescope ACS search for
supernovae associated with X-ray flashes 020903, 040701, 040812,
and 040916. We find strong evidence that XRF 020903 (z=0.25) was
associated with a SN 1998bw-like supernova and confirm this using
optical spectroscopy at t~25 days. We find no evidence, however, for
SN 1998bw-like supernovae associated with the other three events. In
the case of XRF 040701 (z=0.21), we rule out even a faint supernova
similar to SN 2002ap, using template light curves for several local Type
Ic supernovae. For the two cases in which the redshift is not known,
XRFs 040812 and 040916, we derive robust redshift limits, assuming
that they were accompanied by supernovae similar to SN 1998bw, and
compare these limits with photometric redshift constraints provided
by their host galaxies. We supplement this analysis with results
for three additional events (XRFs 011030, 020427, and 030723) and
discuss the observed diversity of supernovae associated with X-ray
flashes and gamma-ray bursts. We conclude that XRF-SNe exist but can
be significantly fainter than SN 1998bw, possibly consistent with the
observed spread in local Type Ibc supernovae.
Title: Detection and imaging of atmospheric radio flashes from cosmic
ray air showers
Authors: Falcke, H.; Apel, W. D.; Badea, A. F.; Bähren, L.; Bekk, K.;
Bercuci, A.; Bertaina, M.; Biermann, P. L.; Blümer, J.; Bozdog, H.;
Brancus, I. M.; Buitink, S.; Brüggemann, M.; Buchholz, P.; Butcher,
H.; Chiavassa, A.; Daumiller, K.; de Bruyn, A. G.; de Vos, C. M.; di
Pierro, F.; Doll, P.; Engel, R.; Gemmeke, H.; Ghia, P. L.; Glasstetter,
R.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel, J. R.; Horneffer,
A.; Huege, T.; Kampert, K. -H.; Kant, G. W.; Klein, U.; Kolotaev, Y.;
Koopman, Y.; Krömer, O.; Kuijpers, J.; Lafebre, S.; Maier, G.; Mathes,
H. J.; Mayer, H. J.; Milke, J.; Mitrica, B.; Morello, C.; Navarra, G.;
Nehls, S.; Nigl, A.; Obenland, R.; Oehlschläger, J.; Ostapchenko,
S.; Over, S.; Pepping, H. J.; Petcu, M.; Petrovic, J.; Plewnia, S.;
Rebel, H.; Risse, A.; Roth, M.; Schieler, H.; Schoonderbeek, G.;
Sima, O.; Stümpert, M.; Toma, G.; Trinchero, G. C.; Ulrich, H.;
Valchierotti, S.; van Buren, J.; van Cappellen, W.; Walkowiak, W.;
Weindl, A.; Wijnholds, S.; Wochele, J.; Zabierowski, J.; Zensus,
J. A.; Zimmermann, D.
Bibcode: 2005Natur.435..313F
Altcode: 2005astro.ph..5383F
The nature of ultrahigh-energy cosmic rays (UHECRs) at energies
>1020eV remains a mystery. They are likely to be of
extragalactic origin, but should be absorbed within ~50Mpc through
interactions with the cosmic microwave background. As there are no
sufficiently powerful accelerators within this distance from the Galaxy,
explanations for UHECRs range from unusual astrophysical sources
to exotic string physics. Also unclear is whether UHECRs consist of
protons, heavy nuclei, neutrinos or γ-rays. To resolve these questions,
larger detectors with higher duty cycles and which combine multiple
detection techniques are needed. Radio emission from UHECRs, on the
other hand, is unaffected by attenuation, has a high duty cycle, gives
calorimetric measurements and provides high directional accuracy. Here
we report the detection of radio flashes from cosmic-ray air showers
using low-cost digital radio receivers. We show that the radiation can
be understood in terms of the geosynchrotron effect. Our results show
that it should be possible to determine the nature and composition of
UHECRs with combined radio and particle detectors, and to detect the
ultrahigh-energy neutrinos expected from flavour mixing.
Title: Supernova 2005aw in IC 4837A
Authors: Morrell, N.; Hamuy, M.; Folatelli, G.; Roth, M.
Bibcode: 2005IAUC.8507....3M
Altcode: 2005IAUC.8507C...1M
N. Morrell, M. Hamuy, G. Folatelli, and M. Roth, Carnegie Supernova
Project, report that a spectrogram (range 380-930 nm) of SN 2005aw
(cf. IAUC 8499), obtained on Apr. 3.33 UT with the Las Campanas 2.5-m
du Pont Telescope (+ WFCCD spectrograph), reveals this to be a type-Ic
supernova, several days past maximum. The spectrum, dominated by
strong Ca II 857.9-nm, along with O I 777.3-nm, Si II 635.5-nm, Na I
589.2-nm, Fe II 508.3-nm, and Mg II 448.1-nm, is very similar to those
of supernovae 1994I and 1987M at 10-11 days after maximum light. An
equivalent width of 0.13 nm was measured for the interstellar Na I D
line arising in the host galaxy.
Title: Integral field spectroscopy of the ultraluminous X-ray source
Holmberg II X-1
Authors: Lehmann, I.; Becker, T.; Fabrika, S.; Roth, M.; Miyaji, T.;
Afanasiev, V.; Sholukhova, O.; Sánchez, S. F.; Greiner, J.; Hasinger,
G.; Costantini, E.; Surkov, A.; Burenkov, A.
Bibcode: 2005A&A...431..847L
Altcode: 2004astro.ph.10458L
We present optical integral field observations of the H II region
containing the ultraluminous X-ray source Holmberg II X-1. We confirm
the existence of an X-ray ionized nebula as the counterpart of the
source owing to the detection of an extended He II λ4686 region
(21× 47 pc) at the Chandra ACIS-S position. An extended blue
object with a size of 11× 14 pc is coincident with the X-ray/He
II λ4686 region, which could indicate that it is either a young
stellar complex or a cluster. We have derived an X-ray to optical
luminosity ratio of L_X/LB≥170, and presumable it is
L_X/LB∼300{-}400 using the recent HST ACS data. We find
a complex velocity dispersion at the position of the ULX. In addition,
there is a radial velocity variation in the X-ray ionized region found
in the He II emission of ±50 km s-1 on spatial scales of
2 3primeprime. We believe that the putative black hole not
only ionizes the surrounding HII gas, but also perturbs it dynamically
(via jets or the accretion disk wind). The spatial analysis of the
public Chandra ACIS-S data reveals a point-like X-ray source and
gives marginal indication of an extended component (ll15% of the total
flux). The XMM-Newton EPIC-PN spectrum of HoII X-1 is best fitted with
an absorbed power law in addition to either a thermal thick plasma
or a thermal thin plasma or a multi-colour disk black body (MCD). In
all cases, the thermal component shows a relatively low temperature
(kT∼0.14{-}0.22 keV). Finally we discuss the optical/X-ray properties
of HoII X-1 with regards to the possible nature of the source. The
existence of an X-ray ionized nebula coincident with the ULX and
the soft X-ray component with a cool accretion disk favours the
interpretation as an intermediate-mass black hole (IMBH). However,
the complex velocity behaviour at the position of the ULX indicates
a dynamical influence of the black hole on the local HII gas.
Title: Comparison of Laser Ion Acceleration from the Front and Rear
Surfaces of Thin Foils
Authors: Fuchs, J.; Sentoku, Y.; Karsch, S.; Cobble, J.; Audebert,
P.; Kemp, A.; Nikroo, A.; Antici, P.; Brambrink, E.; Blazevic, A.;
Campbell, E. M.; Fernández, J. C.; Gauthier, J. -C.; Geissel, M.;
Hegelich, M.; Pépin, H.; Popescu, H.; Renard-Legalloudec, N.; Roth,
M.; Schreiber, J.; Stephens, R.; Cowan, T. E.
Bibcode: 2005PhRvL..94d5004F
Altcode:
The comparative efficiency and beam characteristics of high-energy ions
generated by high-intensity short-pulse lasers (∼1 6×1019
W/cm2) from both the front and rear surfaces of thin metal
foils have been measured under identical conditions. Using direct
beam measurements and nuclear activation techniques, we find that
rear-surface acceleration produces higher energy particles with smaller
divergence and a higher efficiency than front-surface acceleration. Our
observations are well reproduced by realistic particle-in-cell
simulations, and we predict optimal criteria for future applications.
Title: Critical Issues on Magnetic Reconnection in Space Plasmas
Authors: Lui, A. T. Y.; Jacquey, C.; Lakhina, G. S.; Lundin, R.;
Nagai, T.; Phan, T. -D.; Pu, Z. Y.; Roth, M.; Song, Y.; Treumann,
R. A.; Yamauchi, M.; Zelenyi, L. M.
Bibcode: 2005SSRv..116..497L
Altcode:
The idea of expedient energy transformation by magnetic reconnection
(MR) has generated much enthusiasm in the space plasma community. The
early concept of MR, which was envisioned for the solar flare
phenomenon in a simple two-dimensional (2D) steady-state situation,
is in dire need for extension to encompass three-dimensional (3D)
non-steady-state phenomena prevalent in space plasmas in nature like
in the magnetosphere. A workshop was organized to address this and
related critical issues on MR. The essential outcome of this workshop
is summarized in this review. After a brief evaluation on the pros and
cons of existing definitions of MR, we propose essentially a working
definition that can be used to identify MR in transient and spatially
localized phenomena. The word “essentially” reflects a slight
diversity in the opinion on how transient and localized 3D MR process
might be defined. MR is defined here as a process with the following
characteristics: (1) there is a plasma bulk flow across a boundary
separating regions with topologically different magnetic field lines
if projected on the plane of MR, thereby converting magnetic energy
into kinetic particle energy, (2) there can be an out-of-the-plane
magnetic field component (the so-called guide field) present such that
the reconnected magnetic flux tubes are twisted to form flux ropes, and
(3) the region exhibiting non-ideal MHD conditions should be localized
to a scale comparable to the ion inertial length in the direction of
the plasma inflow velocity. This definition captures the most important
3D aspects and preserves many essential characteristics of the 2D
case. It may be considered as the first step in the generalization of
the traditional 2D concept. As a demonstration on the utility of this
definition, we apply it to identify MR associated with plasma phenomena
in the dayside magnetopause and nightside magnetotail of the Earth’s
magnetosphere. How MR may be distinguished from other competing
mechanisms for these magnetospheric phenomena are then discussed.
Title: Event - by - event studies of the discriminative features
of the LDF of charged EAS particles: observable correlations and
nonparametric analyses of multivariate distributions
Authors: Brancus, I. M.; Antoni, T.; Apel, W. D.; Badea, F.; Bekk,
K.; Bercuci, A.; Bertaina, M.; Blümer, J.; Bozdog, H.; Brüggemann,
M.; Buchholz, P.; Chiavassa, A.; Daumiller, K.; Di Pierro, F.; Doll,
P.; Engel, R.; Engler, J.; Feßler, F.; Ghia, P. L.; Gils, H. J.;
Glassteller, R.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel, J. R.;
Kampert, K. -H.; Klages, H. O.; Kolotaev, Y.; Maier, G.; Mathes,
H. J.; Mayer, H. J.; Milke, J.; Mitrica, B.; Morello, C.; Müller,
M.; Navarra, G.; Obenland, R.; Oehlschläger, J.; Ostapchenko, S.;
Over, S.; Petcu, M.; Pierog, T.; Plewnia, S.; Rebel, H.; Risse, A.;
Roth, M.; Schieler, H.; Scholz, J.; Sima, O.; Stümpert, M.; Toma,
G.; Trinchero, G. C.; Ulrich, H.; Valchierotti, S.; van Buren, J.;
Walkowiak, W.; Weindl, A.; Wochele, J.; Zabierowski, J.; Sagromski,
S.; Zimmermann, D.
Bibcode: 2005ICRC....6..361B
Altcode: 2005ICRC...29f.361B
No abstract at ADS
Title: Radio emission of highly inclined cosmic ray air showers
measured with LOPES
Authors: Petrovic, J.; Apel, W. D.; Badea, F.; Bähren, L.; Bekk, K.;
Bercuci, A.; Bertaina, M.; Biermann, P. L.; Blümer, J.; Bozdog, H.;
Brancus, I. M.; Buitink, S.; Brüggemann, M.; Buchholz, P.; Butcher,
H.; Chiavassa, A.; Daumiller, K.; de Bruyn, A. G.; de Vos, C. M.;
Di Pierro, F.; Doll, P.; Engel, R.; Falcke, H.; Gemmeke, H.; Ghia,
P. L.; Glasstetter, R.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel,
J. R.; Horneffer, A.; Huege, T.; Kampert, K. -H.; Kant, G. W.; Klein,
U.; Kolotaev, Y.; Koopman, Y.; Krömer, B.; Kuijpers, J.; Lafebre,
S.; Maier, G.; Mathes, H. J.; Mayer, H. J.; Milke, J.; Mitrica,
B.; Morello, C.; Navarra, G.; Nehls, S.; Nigl, A.; Obenland, R.;
Oehlschläger, J.; Ostapchenko, S.; Over, S.; Pepping, H. J.; Petcu,
M.; Pierog, T.; Plewnia, S.; Rebel, H.; Risse, A.; Roth, M.; Schieler,
H.; Schoonderbeek, G.; Sima, O.; Stümpert, M.; Toma, G.; Trinchero,
G. C.; Ulrich, H.; Valchierotti, S.; van Buren, J.; van Capellen, W.;
Walkowiak, W.; Weindl, A.; Winjnholds, S.; Wochele, J.; Zabierowski,
J.; Zensus, J. A.; Zimmermann, D.
Bibcode: 2005ICRC....6..337P
Altcode: 2005ICRC...29f.337P
No abstract at ADS
Title: High mass Star formation in the giant molecular cloud NGC 6334:
an infrared view
Authors: Persi, P.; Tapia, M.; Roth, M.; Gómez, M.; Marenzi, A. R.
Bibcode: 2005IAUS..227..291P
Altcode:
Sub-Arcsec images in the JHK_s, H_2 and Br_γ of three areas (I(N),
F and NGC 6334 IV (MM3)) of the giant molecular cloud NGC 6334 are
presented. The preliminary results indicate the presence of a deeply
embedded young stellar cluster in the northermost part of the cloud
(I(N)). We have identified the exciting source of the cometary UCHII
NGC 6334 F. This source has an infrared luminosity L_{IRacute;{=}
3 10^3 L_{⊙} and a very steep infrared spectral index. Finally,
a new center of massive star formation associated with the millimeter
peak MM3 has been found east of the bipolar HII region NGC 6334 a.
Title: LOPES30: A digital antenna array for measuring high-energy
cosmic ray air showers
Authors: Nehls, S.; Apel, W. D.; Badea, F.; Bähren, L.; Bekk, K.;
Bercuci, A.; Bertaina, M.; Biermann, P. L.; Blümer, J.; Bozdog, H.;
Brancus, I. M.; Buitink, S.; Brüggemann, M.; Buchholz, P.; Butcher,
H.; Chiavassa, A.; Daumiller, K.; de Bruyn, A. G.; de Vos, C. M.;
Di Pierro, F.; Doll, P.; Engel, R.; Falcke, H.; Gemmeke, H.; Ghia,
P. L.; Glasstetter, R.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel,
J. R.; Horneffer, A.; Huege, T.; Kampert, K. -H.; Kant, G. W.; Klein,
U.; Kolotaev, Y.; Koopman, Y.; Krömer, O.; Kuijpers, J.; Lafebre,
S.; Maier, G.; Mathes, H. J.; Mayer, H. J.; Milke, J.; Mitrica, B.;
Morello, C.; Navarra, G.; Nigl, A.; Obenland, R.; Oehlschläger, J.;
Ostapchenko, S.; Over, S.; Pepping, H. J.; Petcu, M.; Petrovic, J.;
Pierog, T.; Plewnia, S.; Rebel, H.; Risse, A.; Roth, M.; Schieler,
H.; Schoonderbeek, G.; Sima, O.; Stümpert, M.; Toma, G.; Trinchero,
G. C.; Ulrich, H.; Valchierotti, S.; van Buren, J.; van Capellen, W.;
Walkowiak, W.; Weindl, A.; Wijnholds, S.; Wochele, J.; Zabierowski,
J.; Zensus, J. A.; Zimmermann, D.
Bibcode: 2005ICRC....8...45N
Altcode: 2005ICRC...29h..45N
No abstract at ADS
Title: GRB 051016: LCO optical and near-IR imaging.
Authors: Berger, E.; Roth, M.; Gonzalez, S.
Bibcode: 2005GCN..4098....1B
Altcode:
No abstract at ADS
Title: Hadronic multiparticle production in extensive air showers
and accelerator experiments
Authors: Meurer, C.; Blümer, J.; Engel, R.; Haungs, A.; Roth, M.
Bibcode: 2005ICRC....9...17M
Altcode: 2005astro.ph..6755M; 2005ICRC...29i..17M
Using CORSIKA for simulating extensive air showers, we study
the relation between the shower characteristics and features
of hadronic multiparticle production at low energies. We report
about investigations of typical energies and phase space regions
of secondary particles which are important for muon production in
extensive air showers. Possibilities to measure relevant quantities
of hadron production in existing and planned accelerator experiments
are discussed.
Title: GRB 050813: magellan detection of a high redshift galaxy
cluster.
Authors: Gladders, M.; Berger, E.; Morrell, N.; Roth, M.
Bibcode: 2005GCN..3798....1G
Altcode:
No abstract at ADS
Title: A Cosmic Ray Trigger for LOFAR
Authors: Lafebre, S.; Nigl, A.; Apel, W. D.; Badea, F.; Bähren, L.;
Bekk, K.; Bercuci, A.; Bertaina, M.; Biermann, P. L.; Blümer, J.;
Bozdog, H.; Brancus, I. M.; Buitink, S.; Brüggemann, M.; Buchholz,
P.; Butcher, H.; Chiavassa, A.; Daumiller, K.; de Bruyn, A. G.; de
Vos, C. M.; Di Pierro, F.; Doll, P.; Engel, R.; Falcke, H.; Gemmeke,
H.; Ghia, P. L.; Glasstetter, R.; Grupen, C.; Haungs, A.; Heck, D.;
Hörandel, J. R.; Horneffer, A.; Huege, T.; Kampert, K. -H.; Kant,
G. W.; Klein, U.; Kolotaev, Y.; Koopman, Y.; Krömer, O.; Kuijpers,
J.; Maier, G.; Mathes, H. J.; Mayer, H. J.; Milke, J.; Mitrica, B.;
Morello, C.; Navarra, G.; Nehls, S.; Obenland, R.; Oehlschläger, J.;
Ostapchenko, S.; Over, S.; Pepping, H. J.; Petcu, M.; Petrovic, J.;
Pierog, T.; Plewnia, S.; Rebel, H.; Risse, A.; Roth, M.; Schieler,
H.; Schoonderbeek, G.; Sima, O.; Stümpert, M.; Toma, G.; Trinchero,
G. C.; Ulrich, H.; Valchierotti, S.; van Buren, J.; van Capellen, W.;
Walkowiak, W.; Weindl, A.; Wijnholds, S.; Wochele, J.; Zabierowski,
J.; Zensus, J. A.; Zimmermann, D.
Bibcode: 2005ICRC....8..245N
Altcode: 2005ICRC...29h.245N
No abstract at ADS
Title: Cosmic Ray Trigger for LOFAR: First results
Authors: Lafebre, S.; Nigl, A.; Apel, W. D.; Badea, F.; Bähren, L.;
Bekk, K.; Bercuci, A.; Bertaina, M.; Biermann, P. L.; Blümer, J.;
Bozdog, H.; Brancus, I. M.; Buitink, S.; Brüggemann, M.; Buchholz,
P.; Butcher, H.; Chiavassa, A.; Daumiller, K.; de Bruyn, A. G.; de
Vos, C. M.; Di Pierro, F.; Doll, P.; Engel, R.; Falcke, H.; Gemmeke,
H.; Ghia, P. L.; Glasstetter, R.; Grupen, C.; Haungs, A.; Heck, D.;
Hörandel, J. R.; Horneffer, A.; Huege, T.; Kampert, K. -H.; Kant,
G. W.; Klein, U.; Kolotaev, Y.; Koopman, Y.; Krömer, O.; Kuijpers,
J.; Maier, G.; Mathes, H. J.; Mayer, H. J.; Milke, J.; Mitrica, B.;
Morello, C.; Navarra, G.; Nehls, S.; Obenland, R.; Oehlschläger, J.;
Ostapchenko, S.; Over, S.; Pepping, H. J.; Petcu, M.; Petrovic, J.;
Pierog, T.; Plewnia, S.; Rebel, H.; Risse, A.; Roth, M.; Schieler,
H.; Schoonderbeek, G.; Sima, O.; Stümpert, M.; Toma, G.; Trinchero,
G. C.; Ulrich, H.; Valchierotti, S.; van Buren, J.; van Capellen, W.;
Walkowiak, W.; Weindl, A.; Wijnholds, S.; Wochele, J.; Zabierowski,
J.; Zensus, J. A.; Zimmermann, D.
Bibcode: 2005ICRC....8..249L
Altcode: 2005ICRC...29h.249L
No abstract at ADS
Title: The influence of properties of individual hadronic interactions
on the development of extensive air showers
Authors: Hörandel, J. R.; Antoni, T.; Apel, W. D.; Badea, F.; Bekk,
K.; Bercuci, A.; Bertaina, M.; Blümer, J.; Bozdog, H.; Brancus,
I. M.; Brüggemann, M.; Buchholz, P.; Chivassa, A.; Daumiller, K.;
Di Pierro, F.; Doll, P.; Engel, R.; Engler, J.; Feßler, F.; Ghia,
P. L.; Gils, H. J.; Glasstetter, R.; Grupen, C.; Haungs, A.; Heck,
D.; Kampert, K. -H.; Klages, H. O.; Kolotaev, Y.; Maier, G.; Mathes,
H. J.; Mayer, H. J.; Mitrica, B.; Morello, C.; Müller, M.; Navarra,
G.; Obenland, R.; Oehlschläger, J.; Ostapchenko, S.; Over, S.; Petcu,
M.; Pierog, T.; Plewnia, S.; Rebel, H.; Risse, A.; Roth, M.; Schieler,
H.; Scholz, J.; Sima, O.; Stümpert, M.; Toma, G.; Trinchero, G. C.;
Ulrich, H.; Valchierotti, S.; van Buren, J.; Walkowiak, W.; Weindl,
A.; Wochele, J.; Zabierowski, J.; Zagromski, S.; Zimmermann, D.
Bibcode: 2005ICRC....6..121H
Altcode: 2005ICRC...29f.121H
No abstract at ADS
Title: Electric field influence on the radio emission of air showers
Authors: Buitink, S.; Apel, W. D.; Badea, F.; Bähren, L.; Bekk, K.;
Bercuci, A.; Bertaina, M.; Biermann, P. L.; Blümer, J.; Bozdog, H.;
Brancus, I. M.; Brüggemann, M.; Buchholz, P.; Butcher, H.; Chiavassa,
A.; Daumiller, K.; de Bruyn, A. G.; de Vos, C. M.; Di Pierro, F.; Doll,
P.; Engel, R.; Falcke, H.; Gemmeke, H.; Ghia, P. L.; Glasstetter,
R.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel, J. R.; Horneffer,
A.; Huege, T.; Kampert, K. -H.; Kant, G. W.; Klein, U.; Kolotaev,
Y.; Koopman, Y.; Krömer, B.; Kuijpers, J.; Lafebre, S.; Maier, G.;
Mathes, H. J.; Mayer, H. J.; Milke, J.; Mitrica, B.; Morello, C.;
Navarra, G.; Nehls, S.; Nigl, A.; Obenland, R.; Oehlschläger, J.;
Ostapchenko, S.; Over, S.; Pepping, H. J.; Petcu, M.; Petrovic, J.;
Pierog, T.; Plewnia, S.; Rebel, H.; Risse, A.; Roth, M.; Schieler,
H.; Schoonderbeek, G.; Sima, O.; Stümpert, M.; Toma, G.; Trinchero,
G. C.; Ulrich, H.; Valchierotti, S.; van Buren, J.; van Capellen, W.;
Walkowiak, W.; Weindl, A.; Winjnholds, S.; Wochele, J.; Zabierowski,
J.; Zensus, J. A.; Zimmermann, D
Bibcode: 2005ICRC....6..333B
Altcode: 2005ICRC...29f.333B
No abstract at ADS
Title: Comparing active and non-active galaxies
Authors: Márquez, I.; González Delgado, R. M.; Masegosa, J.; Maza,
J.; Moles, M.; Pérez, E.; Roth, M.; RENOIR Consortium; Boisson, C.;
Durret, F.; Joly, M.; Masegosa, J.; Moles, M.
Bibcode: 2005MmSAI..76..158M
Altcode:
In order to understand the fueling mechanism that powers low level AGNs,
a large effort was made by the DEGAS consortium to collect the necessary
observational material for a sample of isolated Seyferts and a well
matched control sample of normal spirals. Based on the analysis of their
NIR images, on long slit spectroscopy at various slit position angles
in the Halpha emission and Calcium triplet absorption lines we conclude
that: (a) the morphology and large scale kinematics of Seyfert hosts and
normal spirals are equivalent; (b) the differences claimed to be related
to the mechanisms driving AGN activity may only be found in details
related to circumnuclear regions still unresolved by our observations;
(c) the presence of drops in the stellar velocity dispersions seems
related to the existence of a central elongated structure, probably an
inner disk, where the CaT equivalent width also reaches a maximum. We
have started a project to study a much larger sample of AGN and normal
host spirals with better spatial and spectral resolutions to see whether
inner disks, velocity drops and young stellar populations are related
phenomena, as suggested by present day numerical simulations. Optical
and NIR HST images of all these galaxies have already been analyzed,
and the spectroscopic data is being collected.
Title: Remote event analyses of LOPES-10
Authors: Badea, A. F.; Apel, W. D.; Bähren, L.; Bekk, K.; Bercuci, A.;
Bertaina, M.; Biermann, P. L.; Blümer, J.; Bozdog, H.; Brancus, I. M.;
Buitink, S.; Brüggemann, M.; Buchholz, P.; Butcher, H.; Chiavassa, A.;
Daumiller, K.; de Bruyn, A. G.; de Vos, C. M.; Di Pierro, F.; Doll,
P.; Engel, R.; Falcke, H.; Gemmeke, H.; Ghia, P. L.; Glasstetter,
R.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel, J. R.; Horneffer,
A.; Huege, T.; Kampert, K. -H.; Kant, G. W.; Klein, U.; Kolotaev,
Y.; Koopman, Y.; Krömer, O.; Kuijpers, J.; Lafebre, S.; Maier, G.;
Mathes, H. J.; Mayer, H. J.; Milke, J.; Mitrica, B.; Morello, C.;
Navarra, G.; Nehls, S.; Nigl, A.; Obenland, R.; Oehlschläger, J.;
Ostapchenko, S.; Over, S.; Pepping, H. J.; Petcu, M.; Petrovic, J.;
Pierog, T.; Plenia, S.; Rebel, H.; Risse, A.; Roth, M.; Schieler,
H.; Schoonderbeek, G.; Sima, O.; Stüpert, M.; Toma, G.; Trinchero,
G. C.; Ulrich, H.; Valchierotti, S.; van Buren, J.; van Capellen, W.;
Walkowiak, W.; Weindl, A.; Wiknholds, S.; Wochele, J.; Zabierowski,
J.; Zensuz, J. A.; Zimmermann, D.
Bibcode: 2005ICRC....6..277B
Altcode: 2005ICRC...29f.277B
No abstract at ADS
Title: Hadrons in a calorimeter measured in air showers and at
an accelerator
Authors: Plewnia, S.; Antoni, T.; Apel, W. D.; Badea, F.; Bekk, K.;
Bercuci, A.; Bertaina, M.; Blümer, J.; Bozdog, H.; Brancus, I. M.;
Brüggemann, M.; Buchholz, P.; Chiavassa, A.; Daumiller, K.; Di Pierro,
F.; Doll, P.; Engel, R.; Engler, J.; Feßler, F.; Ghia, P. L.; Gils,
H. J.; Glasstetter, R.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel,
J. R.; Kampert, K. -H.; Klages, H. O.; Kolotaev, Y.; Maier, G.; Mathes,
H. J.; Mayer, H. J.; Milke, J.; Mitrica, B.; Morello, C.; Müller,
M.; Navarra, G.; Obenland, R.; Oehlschläger, J.; Ostapchenko, S.;
Over, S.; Petcu, M.; Pierog, T.; Rebel, H.; Risse, A.; Roth, M.;
Valchierotti, S.; van Buren, J.; Walkowiak, W.; Weindl, A.; Wochele,
J.; Zabierowski, J.; Zagromski, S.; Zimmermann, D.
Bibcode: 2005ICRC....6...17P
Altcode: 2005ICRC...29f..17P
No abstract at ADS
Title: First determination of the reconstruction resolution of an
EAS radio detector
Authors: Badea, A. F.; Apel, W. D.; Bähren, L.; Bekk, K.; Bercuci, A.;
Bertaina, M.; Biermann, P. L.; Blümer, J.; Bozdog, H.; Brancus, I. M.;
Buitink, S.; Brüggemann, M.; Buchholz, P.; Butcher, H.; Chiavassa, A.;
Daumiller, K.; de Bruyn, A. G.; de Vos, C. M.; Di Pierro, F.; Doll,
P.; Engel, R.; Falcke, H.; Gemmeke, H.; Ghia, P. L.; Glasstetter,
R.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel, J. R.; Horneffer,
A.; Huege, T.; Kampert, K. -H.; Kant, G. W.; Klein, U.; Kolotaev,
Y.; Koopman, Y.; Krömer, O.; Kuijpers, J.; Lafebre, S.; Maier, G.;
Mathes, H. J.; Mayer, H. J.; Milke, J.; Mitrica, B.; Morello, C.;
Navarra, G.; Nehls, S.; Nigl, A.; Obenland, R.; Oehlschläger, J.;
Ostapchenko, S.; Over, S.; Pepping, H. J.; Petcu, M.; Petrovic, J.;
Pierog, T.; Plewnia, S.; Rebel, H.; Risse, A.; Roth, M.; Schieler,
H.; Schoonderbeek, G.; Sima, O.; Stümpert, M.; Toma, G.; Trinchero,
G. C.; Ulrich, H.; Valchierotti, S.; van Buren, J.; van Capellen, W.;
Walkowiak, W.; Weindl, A.; Wijnholds, S.; Wochele, J.; Zabierowski,
J.; Zensus, J. A.; Zimmermann, D.
Bibcode: 2005ICRC....6..273B
Altcode: 2005ICRC...29f.273B
No abstract at ADS
Title: Detection of radio pulses from extensive air showers
Authors: Horneffer, A.; Apel, W. D.; Badea, F.; Bähren, L.; Bekk, K.;
Bercuci, A.; Bertaina, M.; Biermann, P. L.; Blümer, J.; Bozdog, H.;
Brancus, I. M.; Buitink, S.; Brüggemann, M.; Buchholz, P.; Butcher,
H.; Chiavassa, A.; Daumiller, K.; de Bruyn, A. G.; de Vos, C. M.; Di
Pierro, F.; Doll, P.; Engel, R.; Falcke, H.; Koopman, Y.; Krömer,
O.; Kuijpers, J.; Lafebre, S.; Maier, G.; Mathes, H. J.; Mayer,
H. J.; Milke, J.; Mitrica, B.; Morello, C.; Navarra, G.; Nehls, S.;
Nigl, A.; Obenland, R.; Oehlschläger, J.; Ostapchenko, S.; Over,
S.; Pepping, H. J.; Petcu, M.; Petrovic, J.; Pierog, T.; Plewnia,
S.; Rebel, H.; Risse, A.; Roth, M.; Schieler, H.; Schoonderbeek,
G.; Sima, O.; Stümpert, M.; Toma, G.; Trinchero, G. C.; Ulrich,
H.; Valchierotti, S.; van Buren, J.; van Capellen, W.; Walkowiak,
W.; Weindl, A.; Wijnholds, S.; Wochele, J.; Zabierowski, J.; Zensus,
J. A.; Zimmermann, D.
Bibcode: 2005ICRC....6..285H
Altcode: 2005ICRC...29f.285H
No abstract at ADS
Title: Supernova 2004gu
Authors: Morrell, N.; Folatelli, G.; Hamuy, M.; Roth, M.
Bibcode: 2004IAUC.8457....3M
Altcode: 2004IAUC.8457C...1M
N. Morrell, G. Folatelli, M. Hamuy, and M. Roth, Carnegie Supernova
Project, report that a CCD spectrogram of SN 2004gu (IAUC
8454), obtained on Dec. 19.33 UT with the 6.5-m Magellan II
Clay Telescope (+ LDSS2) at Las Campanas, confirms this to be
a type-Ia supernova. The spectrum strongly resembles that of SN
1999aa near maximum light except for the Ca II H and K absorption
which is stronger in SN 2004gu. The expansion velocity inferred
from the minimum of the Si II 635.5-nm absorption is 11600 km/s,
assuming for the host galaxy a recession velocity of 13600 km/s
(derived from the absorption lines present). The Si II 597.2-nm line is apparently absent, indicating a high-luminosity event.
Title: Supernovae 2004gg, 2004gh, 2004gi
Authors: Folatelli, G.; Hamuy, M.; Morrell, N.; Phillips, M.; Roth,
M.; Carnegie Supernova Project
Bibcode: 2004IAUC.8447....3F
Altcode:
G. Folatelli, M. Hamuy, N. Morrell, and M. Phillips, Carnegie Supernova
Project, report that CCD spectra (range 360-900 nm) of SN 2004gg,
SN 2004gh, and SN 2004gi (IAUC 8444) were obtained by M. Roth
on Nov. 25 and 26 UT, using the Magellan II (Clay) telescope (+
LDSS-2 spectrograph) at Las Campanas Observatory. The spectrum of
2004gg closely resembles that of the peculiar type-II SN 1987K,
approximately 1 week after maximum light. SN 2004gh is a type-II
supernova, about 1 month after explosion, showing a prominent
H_alpha P-Cyg profile and an expansion velocity of 4000 km/s, as
inferred from the absorption minimum of H_beta and assuming the
recession velocity of the host galaxy to be 3662 km/s, as given in the NED database. The spectrum of SN 2004gi is that of a type-Ia supernova, about 25 days after maximum light.
Title: The Low-Redshift Carnegie Supernova Program
Authors: Phillips, M. M.; Hamuy, M.; Freedman, W. L.; Persson, S. E.;
Suntzeff, N. B.; Folatelli, G.; Gonzalez, S.; Krzeminski, W.; Morrell,
N.; Murphy, D.; Roth, M.; Li, W.; Filippenko, A.; Carlberg, R.; Maza,
J.; Pinto, P.
Bibcode: 2004AAS...205.7110P
Altcode: 2004BAAS...36.1465P
The Carnegie Supernova Program (CSP) is a 5-year program designed
to 1) provide a precise calibration of Type Ia supernova luminosity
distances based on observations of nearby Type Ia and II supernovae,
and 2) use this calibration to set constraints on the nature of the
dark energy from restframe I-band photometry of high-redshift Type
Ia supernovae. In this paper, we describe the low-redshift portion of
the CSP, the major goal of which is to generate a fundamental dataset
of precise u'BVg'r'i'YJHK light curves and optical spectrophotometry
for 100 Type Ia supernovae (z < 0.07) and 100 Type II supernovae
(z < 0.05). These data will be used to refine techniques for
obtaining distances and reddenings to both types of supernovae, and
to study possible evolutionary effects in Type Ia events. An important
component of the low-z CSP is the near-IR photometry, which offers the
promise of improving the precision of distance determinations due to
the reduced effects of dust extinction and (for Type Ia supernovae)
the smaller intrinsic variation in the peak luminosities at these
wavelengths. The combination of optical and near-IR photometry should
also yield much more reliable dust extinction corrections than can be
obtained from optical data alone. The low-z CSP began taking data
in Sept. 2004, and is projected to run through May 2009. Preliminary
light curves and spectra for the first few supernovae observed are
presented, as is a brief description of the various data reduction
pipelines. This project is supported by NSF grant AST-0306969.
Title: Young and very young stars in NGC 3372, the Carina Nebula
Authors: Tapia, M.; Roth, M.; Vázquez, R. A.; Persi, P.
Bibcode: 2004RMxAC..22...73T
Altcode:
Results are presented of a large-scale imaging photometric study of the
stellar population in the northern part of NGC 3372 with a wavelength
coverage from 0.33 to 2.5 μ m. All observations were made at Las
Campanas Observatory. The sizes of the three stellar clusters, Tr 14,
Tr 15 and Tr 16, were determined by means of star counts. Two-colour and
colour-magnitude diagrams are presented and analyzed for each individual
cluster. The three clusters were found to be at a similar distance from
the Sun, < d > = 2.7 kpc, but with very large scatter in both A[V]
and d. suggesting drastic variations in intracluster dust density. Dust
particle size distribution variations are evident resulting in wide
variations in extinction law. We determined ages between 3 and 60
million years for Tr 15 and between less than 1 and 6 million years
for Tr 14 and Tr 16. The Tr 14 cluster is partially embedded in a dense
molecular cloud that extends towards the southwest reaching its highest
density some three arcmin from the cluster nucleus. The rich UV field
created by the Tr14 stars ionizes most of the visible HII region in its
vicinity and most of the radio HII region Car I. Deep JHK images of the
Car I region reveal the presence of a young, embedded stellar population
that includes several O9-B0 stars and an ultracompact HII region.
Title: New Cepheid Period-Luminosity Relations for the Large
Magellanic Cloud: 92 Near-Infrared Light Curves
Authors: Persson, S. E.; Madore, Barry F.; Krzemiński, W.; Freedman,
Wendy L.; Roth, M.; Murphy, D. C.
Bibcode: 2004AJ....128.2239P
Altcode:
Near-infrared J, H, and Ks photometric measurements of 92
Cepheids in the Large Magellanic Cloud are presented. The stars are
spread over the face of the Cloud, their periods range from 3 to 100
days, and their light curves are sampled at an average of 22 phase
points per star. The intensity-weighted mean magnitudes and colors
define period-luminosity-color (PL or PLC) relations whose uncertainties
due to differential metal abundance and reddening/extinction effects are
minimal. The dispersions in the infrared PL, PLC, and extinction-free
period-Wesenheit relations are extremely small, amounting to less
than 0.10 mag (or 5% in distance). The orientation of the disk plane
of the sample (inclination angle and line of nodes) agrees well with
the 2001 results of van der Marel & Cioni. The PL and PLC fits
are the best-determined such relationships yet found for any sample
of Cepheids and establish a calibration that can be used to precisely
anchor ground- and space-based near-infrared Cepheid data to external
galaxies, as well as back to Cepheid calibrators in the Galaxy. As
an example, we use the 1998 Galactic Cepheid calibration of Gieren
and coworkers to obtain the distance modulus to the centroid of our
LMC sample. The true modulus of the LMC is thus determined to be
18.50+/-0.05 mag. Currently, the dominant source of uncertainty in
this number is the scatter in the Galactic calibrator sample. The PLC
fits and dispersions and the dependence of the PLC on metal abundance
are compared with theoretical versions computed from the 1999 work of
Alibert and coworkers. Overall, the agreement is excellent, indicating
that at near-infrared wavelengths the slope and dispersion of the
PLC depend very weakly on metal abundance. The shift in the JHK PLC
relations is ~0.02 mag for a change in metal abundance from solar to
one-half solar.
Title: Neue Blicke in das Innere der Sonne
Authors: Roth, Markus
Bibcode: 2004S&W....43h..24R
Altcode:
No abstract at ADS
Title: Interaction of Planetary Nebulae with the Interstellar Medium:
A Progress Report
Authors: Kerber, F.; Rauch, T.; Pauli, E. M.; Furlan, E.; Müller,
H. R.; Roth, M.
Bibcode: 2004ASPC..313..272K
Altcode: 2004apnw.conf..272K
We report on the status of our project to study the properties of
Planetary Nebulae (PNe) which are interacting with their ambient
interstellar medium (ISM). In particular, we have discovered proper
motions (PM) for a significant number of interacting PNe. These measured
parameters enable us to derive the space velocity of the central star
(CS) and its PN, which is fundamental to the PN-ISM interaction. The PM
vector and the shape of the PN also directly show that motion of the
CS is the root cause of the asymmetry of the PN and confirm that this
motion is responsible for the PN-ISM interaction. For the first time
Galactic orbits of PNe have been calculated and we have analyzed the
membership of the CSs to specific Galactic stellar populations based
on their kinematics. The knowledge of the space velocity of the CS is
an important stepping stone towards a more quantitative understanding
of PN-ISM interaction.
Title: Reconstruction of the magnetopause and low-latitude boundary
layer topology using Cluster multi-point measurements
Authors: de Keyser, J.; Gustafsson, G.; Roth, M.; Darrouzet,
F.; Dunlop, M.; Rème, H.; Fazakerley, A.; Décréau, P.;
Cornilleau-Wehrlin, N.
Bibcode: 2004AnGeo..22.2381D
Altcode:
Available from http://www.copernicus.org/site/EGU/annales/22/7/2381.htm?FrameEngine=false;
Title: Long slit spectroscopy of a sample of isolated spirals with
and without an AGN
Authors: Márquez, I.; Durret, F.; Masegosa, J.; Moles, M.; Varela,
J.; González Delgado, R. M.; Maza, J.; Pérez, E.; Roth, M.
Bibcode: 2004A&A...416..475M
Altcode: 2003astro.ph.11616M
We present the kinematical data obtained for a sample of active
(Seyfert) and non active isolated spiral galaxies, based on long slit
spectra along several position angles in the Hα line region and, in
some cases, in the Ca triplet region as well. Gas velocity distributions
are presented, together with a simple circular rotation model that
allows us to determine the kinematical major axes. Stellar velocity
distributions are also shown. The main result is that active and
control galaxies seem to be equivalent in all kinematical aspects. For
both subsamples, the departure from pure circular rotation in some
galaxies can be explained by the presence of a bar and/or of a spiral
arm. They also present the same kind of peculiarities, in particular,
S-shape structures are quite common near the nuclear regions. They
define very similar Tully-Fisher relations. Emission line ratios are
given for all the detected HII regions; the analysis of the [NII]/Hα
metallicity indicator shows that active and non-active galaxies have
indistinguishable disk metallicities. These results argue in favour
of active and non-active isolated spiral galaxies having essentially
the same properties, in agreement with our previous results based
on the analysis of near infrared images. It appears now necessary to
confirm these results on a larger sample. Based on observations
made with WHT operated on the island of La Palma by ING in the
Spanish Observatorio del Roque de Los Muchachos of the Instituto
de Astrofísica de Canarias, the European Southern Observatory (La
Silla), Calar Alto Observatory (Almería, Spain) and Las Campanas
Observatories (Chile). Table 3 and Figs. \ref{res_cen_u1395},
5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 28, 30, 32, 34, 36, 38, 40,
42, 44, 46, 48, 50 and 52 are only available in electronic form at
http://www.edpsciences.org Table 5 is only available in electronic
form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)
or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/416/475
Title: Astrophysics of the Knee in the Cosmic Ray Energy Spectrum
Authors: Haungs, A.; Antoni, T.; Apel, W. D.; Badea, F.; Bekk, K.;
Bercuci, A.; Bluemer, H.; Bozdog, H.; Brancus, I. M.; Buettner, C.;
Chilingarian, A.; Daumiller, K.; Doll, P.; Engel, R.; Engler, J.;
Fessler, F.; Gils, H. J.; Glasstetter, R.; Heck, D.; Hoerandel,
J. R.; Kampert, K. -H.; Klages, H. O.; Maier, G.; Mathes, H. J.;
Mayer, H. J.; Milke, J.; Mueller, M.; Obenland, R.; Oehlschlaeger,
J.; Ostapchenko, S.; Petcu, M.; Plewnia, S.; Rebel, H.; Risse, A.;
Risse, M.; Roth, M.; Schatz, G.; Schieler, H.; Scholz, J.; Thouw,
T.; Ulrich, H.; van Buren, J.; Vardanyan, A.; Weindl, A.; Wochele,
J.; Zabierowski, J.; Zagromski, S.
Bibcode: 2004AcPPB..35..331H
Altcode: 2003astro.ph.12295H; 2003astro.ph.12295A
A brief review is given on the astrophysics of cosmic rays in the PeV
primary energy range, i.e. the region of the knee.
Title: B 416 -- a B[e]-SUPERGIANT in Interacting Binary?
Authors: Sholukhova, O.; Fabrika, S.; Roth, M.; Becker, T.
Bibcode: 2004BaltA..13..156S
Altcode: 2004OAst...13..156S
A study of the LBV-like star B 416 in M 33 is presented. Spectrum,
luminosity and variability indicate that this star is a
B[e]-supergiant. We analyze the results of integral field and long slit
spectroscopic observations of 1998--2002. The expansion velocity of a
ring-like nebula surrounding the star is found to be 20 km/s. Ionization
maps and line intensities show that the excitation of gas in the nebula
is very similar to that in H II regions. We discuss spectral variability
of B416 and compare our results with photometric data by Shemmer et
al. (2000). We find its radial velocity variability and argue that the
photometric 8.26 day period is actually a half of the orbital period
16.13±0.07 d. The data indicate that the star is a close interactive
binary with a mass ratio of ∼0.4. The ring-like nebula could be
formed by mass-loss in the equatorial plane. We suggest a possible
connection between B[e]-supergiants and interacting binaries in general.
Title: Energy Spectra and Chemical Composition of Cosmic Rays in
the PEV Region
Authors: Kampert, K. -H.; Antoni, T.; Apel, W. D.; Badea, F.; Bekk,
K.; Bercuci, A.; Bertaina, M.; Blümer, H.; Bozdog, H.; Brancus,
I. M.; Brüggemann, M.; Buchholz, P.; Büttner, C.; Chiavassa, A.;
Chilingarian, A.; Daumiller, K.; Doll, P.; Engel, R.; Engler, J.;
Fessler, F.; Ghia, P. L.; Gils, H. J.; Glasstetter, R.; Haungs, A.;
Heck, D.; Hörandel, J. R.; Klages, H. O.; Kolotaev, Y.; Maier, G.;
Mathes, H. J.; Mayer, H. J.; Milke, J.; Morello, C.; Müller, M.;
Navarra, G.; Obenland, R.; Oehlschläger, J.; Ostapchenko, S.; Petcu,
M.; Plewnia, S.; Rebel, H.; Risse, A.; Risse, M.; Roth, M.; Schatz,
G.; Schieler, H.; Scholz, J.; Thouw, T.; Trinchero, G. C.; Ulrich,
H.; Valchierotti, S.; van Buren, J.; Vardanyan, A.; Walkowiak, W.;
Weindl, A.; Wochele, J.; Zabierowski, J.; Zagromski, S.
Bibcode: 2004otmu.conf..209K
Altcode:
No abstract at ADS
Title: Supernova 2003id in NGC 895
Authors: Hamuy, M.; Roth, M.
Bibcode: 2003IAUC.8228....2H
Altcode: 2003IAUC.8228B...1H
M. Hamuy and M. Roth, Carnegie Observatories, report that a
spectrogram (range 380-930 nm) of SN 2003id (cf. IAUC 8201, 8203),
obtained on Oct. 16.27 UT with the Dupont 2.5-m telescope (+ WFCCD)
at Las Campanas, reveals unusual features. While the spectrum is
characterized by strong absorptions between 466 and 536 nm (presumably
due to Fe II blends) that are seen in other type-Ic events, a strong
unidentified absorption centered at 562 nm distinguishes it from other
type-Ic or type-Ib supernovae. This feature is blended with another
strong absorption centered at 579 nm. The spectrum shows a strong Ca
II triplet line exhibiting a broad P-Cyg profile; adopting the NED
host-galaxy recession velocity of 2288 km/s, the minimum of the Ca
II triplet at 826 nm implies an expansion velocity of -13000 km/s,
which is very high for a supernova that is at least one month old. The
optical lightcurves are also unusual: the V-band flux decreased by
about 0.25 mag between Sept. 19 and 25; a plateau phase (V = 17.25)
ensued through Oct. 3; and the flux has been dropping afterwards,
reaching V = 18.6 on Oct. 16. Further observations at optical and
other wavelengths would be useful.
Title: The detection of stellar velocity dispersion drops in the
central regions of five isolated Seyfert spirals
Authors: Márquez, I.; Masegosa, J.; Durret, F.; González Delgado,
R. M.; Moles, M.; Maza, J.; Pérez, E.; Roth, M.
Bibcode: 2003A&A...409..459M
Altcode: 2003astro.ph..6497M
We analyze the kinematics of the central regions of five isolated
Seyfert spiral galaxies from the DEGAS sample (four with new data
presented in this paper, IC 184, UGC 3223, NGC 2639, NGC 6814, and NGC
6951 from our previous data), by using long slit spectroscopy in the
CaII triplet range (at ~8600 Å) obtained with a 4 m-class telescope. A
drop of the velocity dispersions in the innermost +/-(1-3) arcsec is
observed in four of them, and hinted at in the remaining galaxy (NGC
6814). The available HST images for our sample together with another
nine galaxies with reported velocity dispersion drops are also used
to investigate the presence of morphological inner structures at the
scales of the kinematical drops. Evidence for disk-like shapes is
found in 12 out of the 14 cases. The only exceptions are NGC 6814
and NGC 6951. Existing N-body simulations including stars, gas and
star formation predict that such a drop is most probably due to a
young stellar population born from dynamically cold gas accreted in a
circumnuclear disk formed during an episode of central gas accretion
driven by a bar. The equivalent widths of the calcium triplet lines
for our 5 galaxies have been measured. Even if the profiles could
be formally consistent with constant EW(CaT) values, they seem to
indicate the presence of a local maximum in the regions corresponding
spatially to the drops; if confirmed, this would imply the presence of
a different stellar population, whose properties could help constrain
the models. Based on observations made with the WHT operated on
the island of La Palma by ING in the Spanish Observatorio del Roque
de Los Muchachos of the Instituto de Astrofísica de Canarias.
Title: Structural analysis of periodic surface waves on the
magnetospheric boundary
Authors: De Keyser, J.; Roth, M.
Bibcode: 2003P&SS...51..757D
Altcode:
In situ observations of the flanks of the magnetospheric boundary
(magnetopause and boundary layer) sometimes show periodic surface
waves to be present. We propose a straightforward but powerful
technique for analyzing such periodic boundary waves. The result of
this analysis is a two-dimensional picture of the structure of the
wave in a reference frame that travels tailward with the wave. We give
a few examples of wave patterns that can be recovered from AMPTE/IRM
data. We demonstrate that the proposed method is a valuable tool that
can shed a new light on issues such as the value of the wave speed,
the location of flow vortices in the boundary layer, the identification
of the unstable surface in the case of a Kelvin-Helmholtz instability,
and the non-sinusoidal form of surface waves.
Title: Supernova 2003ho in ESO 235-G58
Authors: Hamuy, M.; Roth, M.
Bibcode: 2003IAUC.8198....3H
Altcode: 2003IAUC.8198C...1H
M. Hamuy and M. Roth, Carnegie Observatories, report that a spectrum
(range 360-900 nm) of SN 2003ho (cf. IAUC 8186), obtained on Sept. 7.04
UT with the Clay 6.5-m telescope (+ LDSS-2) at Las Campanas, shows
that this is a normal type-II supernova with a red continuum and broad
Balmer P-Cyg lines. The minimum of the H_beta absorption yields an
expansion velocity of -5420 km/s (assuming the NED recession velocity
of 4265 km/s for the host galaxy), which suggests that the supernova
is probably one month old.
Title: Open Clusters and Star Formation in the Northern Carina Nebula
Authors: Tapia, M.; Roth, M.; Vázquez, R. A.; Feinstein, A.
Bibcode: 2003RMxAC..18..148T
Altcode: 2003RMxAC..18T.148T
No abstract at ADS
Title: Time-dependent coupling of solar oscillations
Authors: Roth, M.; Stix, M.
Bibcode: 2003A&A...405..779R
Altcode:
We investigate the effects of a large-scale time-dependent flow in the
solar convection zone on the solar p-mode oscillations. The theory of
time-dependent perturbations is applied, and we concentrate on flow
fields that can be described by a single harmonic in space and time. An
iterative method of obtaining approximate analytical solutions to the
equations of the coupled oscillator is outlined. Example calculations
are presented for the special case of two coupling partners. Special
attention is paid to the resonance that occurs when the time dependence
of the flow meets the beat frequency of two p modes.\ We conclude that
time-dependent flow fields in the solar convection zone may diminish
the height of the peaks in the oscillation power spectrum, and may
contribute to their asymmetry, broadening, and effective shift.
Title: Time Structure of the Shower Front as Measured at Haverah
Park above 1019 eV
Authors: Ave Pernas, M. D.; Ave, M.; Knapp, J.; Marchesini, M.; Roth,
M.; Watson, A. A.
Bibcode: 2003ICRC....1..349A
Altcode: 2003ICRC...28..349A
The time structure of the air shower front observed with any particle
detector is largely defined by the development of the shower in the
atmosphere. Shower front structure can thus be correlated with the mass
of the initiating primary particle. We have extended previous work on
this topic, using the Haverah Park array, to explore these features in
events of mean energy 2 × 1019 eV. We compare the measurements with
Monte Carlo calculations made using the CORSIKA/QGSGET model. Data and
simulations show clear azimuthal asymmetries in the time structure,
which relate to the cosmic ray mass composition. The observed time
structure can be best understood if iron primaries are dominant at
these energies, but this conclusion is model dependent.
Title: The Role of Measurements of Muon Arrival Time Distributions
for the Mass Discrimination of High Energy EAS
Authors: Brancus, I. M.; Antoni, T.; Apel, W. D.; Badea, F.; Bekk,
K.; Bercuci, A.; Bertaina, M.; Blümer, H.; Bozdog, H.; Brüggemann,
M.; Buchlolz, P.; Büttner, C.; Chiavassa, A.; Doll, P.; Engel, R.;
Engler, J.; Feßler, F.; Ghia, P. L.; Gils, H. J.; Glasstetter, R.;
Haungs, A.; Heck, D.; Hörandel, J. R.; Iwan, A.; Kampert, K. -H.;
Klages, H. O.; Kolotaev, Y.; Maier, G.; Mathes, H. J.; Mayer, H. J.;
Milke, J.; Morello, C.; Müller, M.; Navarra, G.; Obenland, R.;
Oehlschläger, J.; Ostapchenko, S.; Petcu, M.; Plewnia, S.; Rebel,
H.; Roth, M.; Schieler, H.; Scholz, J.; Thouw, T.; Trinchero, G. C.;
Ulrich, H.; Valchierotti, S.; van Buren, J.; Walkowiak, W.; Weindl,
A.; Wochele, J.; Zabierowski, J.; Zagromski, S.
Bibcode: 2003ICRC....1...41B
Altcode: 2003ICRC...28...41B; 2003ICRC....1...41M
No abstract at ADS
Title: Supernovae 2003bj, 2003bk, 2003bl, and 2003bm
Authors: Phillips, M.; Hamuy, M.; Roth, M.; Morrell, N.
Bibcode: 2003IAUC.8086....2P
Altcode:
M. Phillips and M. Hamuy, Carnegie Observatories, report that a spectrum
(range 380-930 nm) of SN 2003bk, obtained on Mar. 3.28 UT with the
Las Campanas Dupont 2.5-m telescope (+ WFCCD), shows it to be a highly
reddened type-II supernova having a red continuum with a strong H_alpha
line exhibiting a P-Cyg profile. The minimum of the H_alpha absorption
yields an expansion velocity of 7600 km/s, assuming the NED recession
velocity of 1252 km/s for the host galaxy. A spectrum of SN 2003bl,
taken on Mar. 3.35, shows it to be a young type-II supernova with
a blue continuum, weak P-Cyg Balmer lines, and He I at 587.6 nm;
the minimum of the H_beta absorption yields an expansion velocty of
6300 km/s, assuming the NED recession velocity of 4295 km/s for the
host galaxy. Hamuy adds that a spectrum of SN 2003bj (cf. IAUC 8085),
obtained as above on Mar. 2.30 by M. Roth and N. Morrell, shows it to
be a young type-II supernova having a blue continuum with weak H_alpha
and H_beta P-Cyg lines and a well-defined He I 587.6-nm line.
Title: First results obtained by the Cluster STAFF experiment
Authors: Cornilleau-Wehrlin, N.; Chanteur, G.; Perraut, S.; Rezeau, L.;
Robert, P.; Roux, A.; de Villedary, C.; Canu, P.; Maksimovic, M.; de
Conchy, Y.; Lacombe, D. Hubert C.; Lefeuvre, F.; Parrot, M.; Pinçon,
J. L.; Décréau, P. M. E.; Harvey, C. C.; Louarn, Ph.; Santolik,
O.; Alleyne, H. St. C.; Roth, M.; Chust, T.; Le Contel, O.; Staff Team
Bibcode: 2003AnGeo..21..437C
Altcode:
The Spatio Temporal Analysis of Field Fluctuations (STAFF) experiment
is one of the five experiments, which constitute the Cluster Wave
Experiment Consortium (WEC). STAFF consists of a three-axis search coil
magnetometer to measure magnetic fluctuations at frequencies up to
4 kHz, a waveform unit (up to either 10 Hz or 180 Hz) and a Spectrum
Analyser (up to 4 kHz). The Spectrum Analyser combines the 3 magnetic
components of the waves with the two electric components measured by
the Electric Fields and Waves experiment (EFW) to calculate in real
time the 5 × 5 Hermitian cross-spectral matrix at 27 frequencies
distributed logarithmically in the frequency range 8 Hz to 4 kHz. The
time resolution varies between 0.125 s and 4 s. The first results show
the capabilities of the experiment, with examples in different regions
of the magnetosphere-solar wind system that were encountered by Cluster
at the beginning of its operational phase. First results obtained by
the use of some of the tools that have been prepared specifically for
the Cluster mission are described. The characterisation of the motion
of the bow shock between successive crossings, using the reciprocal
vector method, is given. The full characterisation of the waves
analysed by the Spectrum Analyser, thanks to a dedicated program
called PRASSADCO, is applied to some events; in particular a case of
very confined electromagnetic waves in the vicinity of the equatorial
region is presented and discussed.
Title: Sh2-68 - A Planetary Nebula Leaving it's Mark on the
Interstellar Medium
Authors: Kerber, F.; Guglielmetti, F.; Mignani, R.; Roth, M.
Bibcode: 2003IAUS..209..525K
Altcode:
No abstract at ADS
Title: Near and Mid-Infrared Images of the Massive Star-Forming
Complex G 9.62+0.19
Authors: Tapia, M.; Persi, P.; Roth, M.; Marenzi, A. R.; Testi, L.;
Vanzi, L.
Bibcode: 2003RMxAC..15..207T
Altcode:
A near- and mid-infrared study of the star-formation complex G
9.62+0.19 is presented. dIt includes photometrically calibrated images
through wide-band JHK and narrow-band Br gamma , H[2], and 12.5 mu m
filters. The observations were made at Las Campanas, La Silla and the
Observatorio Astronómico Nacional-San Pedro Mártir observatories.
Title: Detectability of large-scale flows in global helioseismic
data - A numerical experiment
Authors: Roth, M.; Howe, R.; Komm, R.
Bibcode: 2002A&A...396..243R
Altcode:
Convective motions affect the solar p-modes by shifting their
frequencies. In comparison to the frequency splitting caused by the
differential rotation, this is only a small additional effect. As the
spatial resolution of the inversions for the differential rotation
becomes better, it is important to know how these additional frequency
shifts modify the splitting coefficients and how these two effects might
be disentangled. Therefore we carry out a numerical experiment. We use
quasi-degenerate perturbation theory to create frequencies of p-modes
that are affected by differential rotation and by large-scale flows. The
simulated frequency sets are analyzed and inverted for differential
rotation. We use changes in the (l, nu ) coverage, the multiplets,
and the inversion results as diagnostics to draw conclusions about the
detectability of large-scale flows in global helioseismic data. The
result is a detectability limit of the order of 10 m s-1
for large-scale flows in the convection zone. A sectoral poloidal
flow with greater amplitude will lead to a noticeable distortion of
the rotation rate, while a zonal poloidal flow with greater amplitude
will lead to distorted even-a coefficients and disrupted multiplets.
Title: Dynamics of the solar granulation. VIII. Time and space
development
Authors: Nesis, A.; Hammer, R.; Roth, M.; Schleicher, H.
Bibcode: 2002A&A...396.1003N
Altcode:
We study the evolution of the granulation dynamics from
the observational point of view. Based on series of excellent
spectrograms taken at the VTT, Observatorio del Teide (Tenerife), in
1999, we calculated temporal - spatial maps of the Doppler velocity,
line width, and intensity in order to track the dynamical behavior
of these observables at different positions along the spectrograph
slit. The Doppler velocity map reveals a granular dynamical time - the
characteristic time associated with the decay of the Doppler velocity
- of approximately 2 min, while the line width map does not show
any characteristic time scale but rather a strong intermittence. The
intensity map reveals the life time of the granulation as it is given
in the literature. The granular dynamical time is practically equal
to the value determined from spectrograms taken at the solar minimum
1994; so the dynamical time does not show any change over the solar
cycle. The stochastic properties of the Doppler velocity and intensity
data samples are studied (i) by means of their statistical moments and
(ii) theoretically using presupposed model distributions. For the latter
we estimated the distributions' parameters by means of the maximum
likelihood method. The histograms of the Doppler velocity variations
point to an asymmetric model distribution, while the histograms of the
intensity variations infer a symmetric one. The intensity variations
can be described well by a Gaussian probability density function, while
the Doppler velocity variations are described by the double exponential
(Gumbel) distribution, an asymmetric probability function. A remarkable
result of the statistical analysis based on both series of observations
in 1994 and 1999 is the unambiguous lack of flows with large velocity
amplitudes within the intergranular space.
Title: Supernova 2002jz in UGC 2984
Authors: Hamuy, M.; Roth, M.; Morrell, N.
Bibcode: 2002IAUC.8037....2H
Altcode: 2002IAUC.8037B...1H
M. Hamuy, Carnegie Observatories, reports spectroscopic observations
(range 380-725 nm) of SN 2002jz made by M. Roth and N. Morrell on
Dec. 27.22 UT with the Las Campanas Observatory Dupont 2.5-m telescope
(+ Modular Spectrograph). The spectrum bears some resemblance to
that of the type-Ic SN 1994I taken 10 days past maximum (Filippenko et
al. 1995, Ap.J. 450, L11). Both supernovae show a strong Na I D 589.2-nm
line exhibiting a P-Cyg profile and prominent blends of Fe II lines
between 400 and 470 nm. However, SN 2002jz shows an evident absorption
(possibly H-alpha) at 644 nm (rest wavelength) that is not present in
SN 1994I, suggesting perhaps an intermediate IIb-type supernova. Na I D
interstellar lines at the redshift of the host galaxy can be seen with
an equivalent width of 0.1 nm, which suggests significant reddening
by dust.
Title: Resonant phenomena of hydromagnetic waves in non-uniform
space plasmas
Authors: Cadez, V. M.; DeKeyser, J.; Roth, M.
Bibcode: 2002PSST...11A..69C
Altcode:
In non-uniform plasmas, linear magnetohydrodynamic waves can get
into resonant interaction with the background plasma at locations
where propagating waves and local modes, existing in regions of
pronounced non-uniformity, satisfy the resonant condition of phase
synchronism. This leads to a resonant excitation of local modes and
growth of their amplitudes. Consequently, the effect of dissipation
becomes important which eventually limits the amplitudes to finite
values in domains of around resonances. The incident wave then loses its
energy and a process known as the resonant wave absorption occurs. In
a non-static background plasma, a non-uniform macroscopic mass flow can
act as a free energy source, causing phenomena of resonant instability
of local modes and over-reflection of incident waves when reflected
waves gain energy from the flow. Such resonant processes may appear
in magnetic structures in the solar corona, in sunspots, in planetary
magnetopauses, bowshocks and magnetotails contributing to energy
transfer and transports of other physical quantities. Some of these
phenomena can be related to locally enhanced physical quantities
as detected by satellites. In this paper, we present a number of
analytical and computational approaches in treating the resonant wave
behaviour in non-uniform plasma configurations relevant to solar and
terrestrial conditions.
Title: Trying to bring the magnetopause to a standstill
Authors: De Keyser, J.; Darrouzet, F.; Roth, M.
Bibcode: 2002GeoRL..29.1453D
Altcode: 2002GeoRL..29j..93D
Satellite observations of the magnetospheric boundary (magnetopause
and boundary layer) show it to be a very dynamic place, in part due to
boundary motion. We present a straightforward technique for identifying
boundary motion and for recovering magnetopause and boundary layer
structure in a reference frame that comoves with the boundary, that is,
a frame in which it is at a standstill.
Title: Intense ion beams accelerated by ultra-intense laser pulses
Authors: Roth, Markus; Cowan, T. E.; Gauthier, J. C.; Vehn,
J. Meyer-Ter; Allen, M.; Audebert, P.; Blazevic, A.; Fuchs, J.;
Geissel, M.; Hegelich, M.; Karsch, S.; Pukhov, A.; Schlegel, T.
Bibcode: 2002AIPC..611..199R
Altcode: 2002sfp..conf..199R
The discovery of intense ion beams off solid targets irradiated
by ultra-intense laser pulses has become the subject of extensive
international interest. These highly collimated, energetic beams of
protons and heavy ions are strongly depending on the laser parameters as
well as on the properties of the irradiated targets. Therefore we have
studied the influence of the target conditions on laser-accelerated ion
beams generated by multi-terawatt lasers. The experiments were performed
using the 100 TW laser facility at Laboratoire pour l'Utilisation
des Laser Intense (LULI). The targets were irradiated by pulses up to
5×1019 W/cm2 (~300 fs,λ=1.05 μm) at normal
incidence. A strong dependence on the surface conditions, conductivity,
shape and purity was observed. The plasma density on the front and
rear surface was determined by laser interferometry. We characterized
the ion beam by means of magnetic spectrometers, radiochromic film,
nuclear activation and Thompson parabolas. The strong dependence of
the ion beam acceleration on the conditions on the target back surface
was confirmed in agreement with predictions based on the target normal
sheath acceleration (TNSA) mechanism. Finally shaping of the ion beam
has been demonstrated by the appropriate tailoring of the target. .
Title: Kopplung globaler Eigenschwingungen der Sonne durch
Konvektion Title: Kopplung globaler Eigenschwingungen der Sonne
durch Konvektion Title: Coupling of global natural oscillations of
the sun by convection;
Authors: Roth, Markus
Bibcode: 2002PhDT.......168R
Altcode:
No abstract at ADS
Title: Well Sampled Light Curves of the Nearby Type Ia Supernova
1999ac
Authors: Labbe, E.; Galaz, G.; Krisciunas, K.; Suntzeff, N.; Espinoza,
J.; Gonzalez, D.; Phillips, M. M.; Roth, M.; Germany, L.
Bibcode: 2001AAS...199.4702L
Altcode: 2001BAAS...33.1370L
We present the most complete infrared (JHK) and optical (BVRI) light
curves ever obtained of a Type Ia Supernova: SN 1999ac. The SN ocurred
in the outer part of the Sc galaxy NGC 6063. It was discovered two weeks
before maximum light, and observations were begun shortly thereafter. We
present 39 nights of optical photometry spanning 144 days, plus 33
nights of infrared photometry spanning 93 days. Spectroscopically, SN
1999ac closely resembled SN 1991T in displaying a spectrum dominated
by strong Fe III absorption ~ 2 weeks before maximum light. However,
by maximum the spectrum of SN 1999ac was essentially ``normal'', and
in this sense resembled more the ``peculiar''SN 1999aa. Following
the methods of Phillips et al. (1999) and Krisciunas et al. (2000)
we derive a total extinction towards this object of AV =
0.51 mag, although it is not clear that these methods can be applied
to 91T/99aa-like events. From the measured radial velocity of the
host galaxy, corrected for our motion with respect to the Local Group
and the microwave background, we obtain MV ~ -19.7 assuming
H0 = 65 km/sec/Mpc. Combining the optical and IR photometry,
we produce the best bolometric light curve to date of a 91T/99aa-like
event. This research is supported in part by the CTIO REU/PIA Program,
which is funded by the National Science Foundation.
Title: First Results of the Spatio-Temporal Analysis of Field
Fluctuations Experiment (STAFF) of Cluster
Authors: Cornilleau-Wehrlin, N.; Chanteur, G.; Perraut, S.; Rezeau, L.;
Robert, P.; Roux, A.; Sahraoui, F.; Belmont, G.; Chust, T.; Le Contel,
O.; Maksimovic, M.; Hubert, D.; Lacombe, C.; Lefeuvre, F.; Parrot,
M.; Pincon, J.; Décréau, P. M.; Harvey, C. C.; Louarn, P.; Kofman,
W.; Santolik, O.; Gurnett, D. A.; Alleyne, H. S.; Gough, M. P.; Andre,
M.; Gustafsson, G.; Pedersen, A.; Roth, M.; Pellinen, R.; Balogh, A.
Bibcode: 2001AGUFMSM12C..03C
Altcode:
STAFF experiment is one of the five experiments which constitute
the Cluster Wave Experiment Consortium (WEC). STAFF consists of a
three-axis search coil magnetometer to measure magnetic fluctuations at
frequencies up to 4 kHz, a wave form unit (up to either 10 Hz or 180
Hz) and a spectrum analyzer (up to 4 kHz) (Cornilleau-Wehrlin et al,
1997). The spectrum analyzer combines the 3 magnetic components of the
waves with the two electric components measured by EFW to calculate
in real time the 5  5 Hermitian cross-spectral matrix at 27
frequencies distributed logarithmically in the frequency range 8 Hz to 4
kHz. The time resolution varies between 0.125s and 4s. Different tools
have been prepared (Cornilleau et al., 2000), specific to the Cluster
related studies. The first results presented will show the capabilities
of the experiment in different key regions of the magnetosphere-solar
wind system encountered by Cluster, using different specific tools.
Title: Transients at the dusk side magnetospheric boundary: Surface
waves or isolated plasma blobs?
Authors: De Keyser, J.; Darrouzet, F.; Roth, M.; Vaisberg, O. L.;
Rybjeva, N.; Smirnov, V.; Avanov, L.; Nemecek, Z.; Safrankova, J.
Bibcode: 2001JGR...10625503D
Altcode:
We revisit Interball-Tail and Magion-4 observations of the dusk side
magnetospheric boundary on February 15-16, 1996. The observed transient
behavior of the boundary can be interpreted in terms of surface waves
or as the manifestation of isolated magnetosheath plasma entities
embedded in the magnetosphere. We examine the arguments for each
of these interpretations with high time resolution magnetic field
and plasma data and by exploiting the dual-satellite nature of the
observations. We find strong evidence for magnetic field and flow
vortices near the magnetospheric boundary and hence for the existence
of flux tubes with helicoidal field lines; such structures can be
associated with both interpretations. The cross-correlation between
the dual satellite observations and the apparent periodicity strongly
suggest a Kelvin-Helmholtz surface wave, although other interpretations
are not impossible. In any case, the observations for this particular
event allow us to derive constraints on surface wave generation
mechanisms and on scenarios that could account for the presence of
isolated plasma elements in the magnetosphere.
Title: Anticorrelated Coupling p-Modes
Authors: Roth, M.
Bibcode: 2001ApJ...559.1165R
Altcode:
Using data from the Michelson Doppler Imager and the Global Oscillation
Network Group project, we demonstrate that there exists an excess of
anticorrelated power variations of pairs of solar p-modes. We find a
possible explanation for this behavior in the influence of poloidal
velocity fields, which may lead to coupling of p-modes that results
in an energy redistribution among the solar oscillations.
Title: Dynamics of the solar granulation. VII. A nonlinear approach
Authors: Nesis, A.; Hammer, R.; Roth, M.; Schleicher, H.
Bibcode: 2001A&A...373..307N
Altcode:
We investigate the attractor underlying the granular phenomenon by
applying nonlinear methods to series of spectrograms from 1994 and
1999. In the three-dimensional phase space spanned by intensity, Doppler
velocity, and turbulence (line broadening), the granulation attractor
does not fill the entire phase space, as expected from the high
Reynolds and Rayleigh numbers of the photospheric plasma, but rather
shows a highly structured form. This could be due to the correlations
between intensity, turbulence, and velocity, which represent also
the Reynolds stress. To obtain insight into the dimensionality of the
attractor, we use the time lag method, a nonlinear method that enables
us to get information about the underlying attractor of a dynamical
system (granulation) from the measurement of one physical quantity
only. By applying this method to the observed Doppler velocities,
we show that the granulation attractor can be described by three
independent variables. The dimension of the granulation attractor
seems to be independent of the appearance of big granules and shear
flow. Furthermore, the power analysis of the Doppler velocity shows
power down to the spatial resolution of the instrument (0.3 arcsec). In
order to decide whether the power at the smallest scales is real or
noise, we use again the time lag method in combination with either a
high pass digital or wavelet filter, which filters out the large wave
numbers. It appears that the power at the smallest scales represents
a real signal.
Title: Detectability of Large-Scale Convection in Global Helioseismic
Data
Authors: Roth, M.; Howe, R.; Komm, R. W.
Bibcode: 2001AGUSM..SP31A08R
Altcode:
Convection affects the solar p-modes by additonally shifting the
frequencies. This effect is small in comparison to the frequency
splitting caused by the differential rotation. But, as the spatial
resolution of the inversions for the differential rotation becomes
better, it is important to know how these additional frequency shifts
are blended into the splitting coefficients and how both might be
disentangled. Therefore we carry out a numerical experiment. We
calculate with quasi-degenerate perturbation theory the frequencies
of p-modes that are affected by differential rotation and large-scale
convection cells. This simulated data are inverted for differential
rotation, and on that basis upper limits for the detectability of
large-scale convection in global helioseismic data are derived.
Title: Dynamics of the solar granulation - On the Time Variation of
the Granular Flow
Authors: Nesis, A.; Hammer, R.; Roth, M.; Schleicher, H.; Soltau,
D.; Staiger, J.
Bibcode: 2001SoPh..200...11N
Altcode:
The emergence and evolution of large granules shows thegranular dynamics
particularly well. We therefore investigate the time dependence of
the convective flows within a regular and an exploding granule. The
observational material for this study was taken at the center of the
solar disk with the German VTT in Izaña (Tenerife, Spain) during
an observing campaign in the year 1994. It consists of series of
spectrograms of high spatial resolution, which were digitized and
processed with wavelet techniques. Among other features, our data show
the dynamical portrait of a regular and an exploding granule. We can
follow their temporal evolution over more than 12 min. Using absorption
lines of different strength we are able to see the dynamical change
of both granules at several heights within the first 200 km above
τ5000=1. The observations reveal significant changes of
the convective flow of both granules over time as well as over height,
which are discussed in detail.
Title: Anti-correlated Coupling p-Modes
Authors: Roth, M.
Bibcode: 2001AGUSM..SP31A09R
Altcode:
Using data from the MDI instrument and the GONG project we demonstrate
that there exists an excess of anti-correlated power variations
of pairs of solar p-modes. We find a possible explanation for this
behavior in the influence of poloidal velocity fields, which may lead
to coupling of p-modes that results in an energy redistribution among
the solar oscillations.
Title: Development of the Dynamics of Solar Granulation in Space
and Time
Authors: Nesis, A.; Hammer, R.; Roth, M.; Schleicher, H.
Bibcode: 2001AGUSM..SP41B03N
Altcode:
We address the evolutionary behavior of the granulation dynamics from
an observational point of view by analyzing a series of excellent
spectrograms taken at the VTT in Izaña/Tenerife (Spain) in 1999. We
present temporal-spatial maps of the Doppler velocity, turbulent
line broadening, and intensity variations, which allow us to study
the dynamical behavior of these observables at different positions
on the solar surface. The Doppler velocity maps reveal a granular
dynamical time -- the time associated with the Doppler velocity decay
-- of approximately 2 min, while the turbulence map does not show
any characteristic time but a strong intermittency. The intensity
map reveals the life time of the granulation as it is given in the
literature. The granular dynamical time is practically equal to the
value determined from spectrograms taken during the solar minimum in
1994; so the dynamical time does not show any change over half a solar
cycle. The stochastical properties of the Doppler velocity and intensity
data samples were studied (i) by means of their statistical moments
and (ii) by using theoretically model distributions. For the latter
we estimated the distributions' parameters by means of the maximum
likelihood method. The histograms of the Doppler velocity variations
point to an asymmetrical model distribution, while the histograms of
the intensity variations infer a symmetrical one. Thus the intensity
variations can be described well by a Gaussian probability density
function, while the Doppler velocity variations can be described by a
Gumbel distribution an asymmetrical probability function. A remarkable
result of the statistical analysis of both the observations from 94
and 99 is the unambiguous lack of flows with large velocity amplitudes
within the intergranular space.
Title: Physical Conditions and Current Massive Star Formation in
NGC 3603
Authors: Tapia, M.; Bohigas, J.; Pérez, B.; Roth, M.; Ruiz, Ma. T.
Bibcode: 2001RMxAA..37...39T
Altcode:
New optical and near-infrared observations of the Galactic H II region
NGC 3603 have been obtained in order to explore the interaction of the
central starburst cluster HD 97950 with the remains of the molecular
cloud and the formation of new generations of OB-type stars. Ample
evidence for continuous stellar formation activity proceeding from north
to south over the past three to six million years is presented. K-band
excesses are found in 50 objects which are the youngest OB-type stars
in the region. Nearly 80% is clustered or associated to signposts
of recent star formation. Several sources are found near the tips of
the ionization fronts produced by HD 97950. Some of these are young OB
stars with water masers in their vicinity and/or associated to isolated
radio-continuum emission peaks. Near the centre of the active star
formation region that is further away from HD 97950, the Irs 9 cluster,
12 OB-type stars (out of 16) with large excess emission beyond 2 μm
are found within a 15 arcsec radius. The most massive star of this
new stellar generation in NGC 3603 is an O5--O6 star.
Title: Book Review: Aéronomie - physique et chimie de l'atmosphère
/ Bibliothèque des Universités - Physique, De Boeck Université,
Bruxelles, 207 pp., 2000, ISBN 2-8041-3456-3.
Authors: Roth, M.
Bibcode: 2001C&T...117...30R
Altcode:
No abstract at ADS
Title: Comparing mode frequencies from MDI and GONG
Authors: Howe, R.; Hill, F.; Basu, S.; Christensen-Dalsgaard, J.;
Komm, R. W.; Munk Larsen, R.; Roth, M.; Schou, J.; Thompson, M. J.;
Toomre, J.
Bibcode: 2001ESASP.464..137H
Altcode: 2001soho...10..137H
We present results of analyses of MDI and GONG time series covering
the same time intervals, and using both the MDI and GONG peakbagging
algorithms. We discuss some of the likely causes of differences between
the inferred frequencies and frequency splittings. In addition, we
consider the effect of these differences on the results of inversions
for the solar internal rotation and sound speed.
Title: Effect of time-dependent velocity fields on solar oscillations
Authors: Roth, Markus; Stix, Michael
Bibcode: 2001ESASP.464..243R
Altcode: 2001soho...10..243R
Velocity fields in the solar convection zone have various influences on
the solar oscillations. Besides the excitation they lead to splittings
into multiplets in the case of differential rotation and to frequency
shifts of the multiplets components in the case of convection cells. As
the velocity fields are time-dependent, these frequency shifts must be
time-dependent as well. Moreover, the amplitudes and therefore the mode
energies of the solar oscillations are affected. We use time-dependent
perturbation theory to show how the p-mode frequencies and energies
are influenced by non-stationary velocity fields and present possible
effects on the line profiles in the power spectra.
Title: Application of Neural Networks in Astroparticle Physics
Authors: Roth, Markus
Bibcode: 2001nffs.conf..409R
Altcode:
No abstract at ADS
Title: The STELLA Project: a 1.2m Robotic Telescope for
High-resolution Echelle Spectroscopy
Authors: Strassmeier, K. G.; Granzer, T.; Weber, M.; Woche, M.;
Hildebrandt, J.; Arlt, K.; Washuettl, A.; Bauer, S. -M.; Paschke,
J.; Roth, M.; Schmitt, J. H. M. M.; Hempelmann, A.; Hagen, A.
Bibcode: 2001AGM....18.P232S
Altcode:
In this poster, we present a brief overview and report on the status
of the STELLA project (abbreviation for STELLar Activity; see also
poster by Weber et al.). The STELLA telescope at the Teide Observatory
on the Island of Tenerife will be the first robotic telescope that
feeds a bench-mounted echelle spectrograph with a set of 50 and 100μm
fibres and provides resolutions of between 50,000 and 25,000. The
spectrograph is a FEROS-like design and will be located in a separated
temperature-controlled room within the STELLA building to guarantee
long-term stability. The building will be a roll-off roof building
capable of hosting two telescopes. First light for STELLA-1 is planned
for fall 2002.
Title: Electroweak Precision Physics at e+e-
Colliders with RACOON WW
Authors: Denner, A.; Dittmaier, S.; Roth, M.; Wackeroth, D.
Bibcode: 2001AIPC..541...40D
Altcode: 2001thep.conf...40D
No abstract at ADS
Title: Extinction distances of Planetary Nebulae interacting with
the interstellar medium
Authors: Pirzkal, N.; Kerber, F.; Roth, M.
Bibcode: 2000AAS...197.0610P
Altcode: 2000AAS...197..610P; 2000BAAS...32.1399P
Distances to Planetary Nebulae (PNe) are notoriously unreliable. It
is known that statistical methods such as the different versions
of the Shklovsky--derived distance scales can not be applied to
individual objects with any confidence. Various methods to estimate the
distance of individual PN have been successfully applied in the past,
e.g. using trigonometric parallaxes, radio and optical expansion rates,
the central star's atmosphere, or the nature of companions in binary
systems. However, these have the drawback of relying on some special
properties of a PN, and require various combinations of very high S/N
observations, of large time bases, and of extensive modeling. In the
end, these methods can only be applied to a very small number of PNe. As
a result, after more than 30 years of research, accurate and reliable
distances are known for less than 5 2000 or so Galactic PNe. This is the
largest single obstacle to a better understanding of the fundamental
properties of PNe. One method which does not require us to make any
assumptions about the PN and which can be applied to all PNe close
to the Galactic plane is the extinction distance method. This method
relies on the fact that most of the stars surrounding a target PN are
either Main-Sequence stars or giants with known intrinsic colors. Using
these, together with an a-priori dust extinction law, an extinction
vs. distance relation can be determined for the field. We have applied
this method to several PN fields which were observed in the B,V,Rc,
and Ic bands. We report here on the first results and present extinction
vs. distance relations in the direction of our target PNe. A discussion
about the accuracy of the method and the derived distances is included.
Title: Near-infrared photometry of isolated spirals with and without
an AGN --- II. Photometric properties of the host galaxies
Authors: Márquez, I.; Durret, F.; Masegosa, J.; Moles, M.; González
Delgado, R. M.; Marrero, I.; Maza, J.; Pérez, E.; Roth, M.
Bibcode: 2000A&A...360..431M
Altcode: 2000astro.ph..6247M
We present here the analysis of morphological and photometric properties
of a sample of isolated spirals with (18) and without (11) an active
nucleus, based on near-infrared imaging in the J and K' bands (Paper
I). The aim of that comparative analysis is to find the differential
properties that could be directly connected with the phenomenon of
nuclear activity. We stress the importance of using isolated objects for
that purpose. Our study shows that both sets of galaxies are similar
in their global properties: they define the same Kormendy relation,
their disk components share the same properties, the bulge and disk
scale lengths are correlated in a similar way, bar strengths and
lengths are similar for primary bars. Our results therefore indicate
that hosts of isolated Seyfert galaxies have bulge and disk properties
comparable to those of isolated non active spirals. Central colors
(the innermost 200 pc) of active galaxies are redder than the centers
of non active spirals, most probably due to AGN light being re-emitted
by the hot dust and/or due to circumnuclear star formation, through
the contribution of giants/supergiants. Central to our analysis is
the study of the possible connection between bars and similar non
axisymmetric structures with the nuclear fuelling. We note that only
one of the Seyfert galaxies in our sample, namely ESO 139-12, does
not present a primary bar. But bars are equally present in active
and control objects. The same applies to secondary bars. Not all the
active galaxies we have observed have them, and some control galaxies
also present such central structures. Secondary central elongations
(associated with secondary bars, lenses, rings or disks) may be
somewhat different, but this result should be confirmed with larger
samples. We note that numerical models indicate that such secondary bars
are not strictly necessary to feed the central engine when a primary
bar is present. Our results show that down to scales of 100-300 pc,
there are no evident differences between active and non active spiral
galaxies. Based on data obtained at: the European Southern Observatory,
La Silla, Chile, the Télescope Bernard Lyot, Calar Alto Observatory,
Las Campanas Observatory. Also based on observations made with the
NASA/ESA Hubble Space Telescope, obtained from the data archive at
the Space --- II. Photometric properties of the host galaxies
Title: Ulysses observations of sector boundaries at aphelion
Authors: De Keyser, J.; Roth, M.; Forsyth, R.; Reisenfeld, D.
Bibcode: 2000JGR...10515689D
Altcode:
We study a sample of sector boundaries observed by Ulysses near its
early 1998 aphelion at 5.4 AU. We relate these sector boundaries to
solar wind structure seen by Wind at 1 AU, guided by a hydrodynamic
simulation. For each Ulysses sector boundary we are able to identify
a corresponding 1 AU sector boundary, except when strong transients
are present. Sector boundaries appear embedded in complex plasma
structures that generally are in a state of pressure balance. Minimum
variance analysis confirms the tangential discontinuity nature of the
heliospheric current sheet (HCS) and indicates that the current sheet
tends to be inclined more steeply than at 1 AU (HCS normal closer to
the equatorial plane and nearly radially outward). We discuss evidence
for the nonplanarity of the current sheet. Magnetic field depressions
are characteristic features of the sector boundaries. We attribute
them to particles that are magnetically confined inside the current
sheet and that carry the diamagnetic current responsible for the large
magnetic field rotation.
Title: Dynamics of the Granulation: A Non-Linear Approach
Authors: Nesis, A.; Hammer, R.; Roth, M.; Schleicher, H.
Bibcode: 2000SPD....31.0101N
Altcode: 2000BAAS...32..801N
Observables like Doppler velocity, intensity, and turbulence (line
broadening) can provide insight into the physics of the granulation
-- i.e., into the physics of the upper solar convective layers. So
far, measurements of these observables have been processed by means
of a power and coherence analysis, which is actually connected
with the physical concept of modes in linear theories. The upper
solar convective layer, however, is a highly nonlinear dissipative
system. According to theoretical considerations, such a system may
approach a strange attractor in its phase space with time. Based on a
series of spectrograms taken at the German VTT on Tenerife in the summer
of 1999, we address the granulation attractor and its dimension from
an observational point of view. In the three-dimensional phase space
spanned by the observables intensity, Doppler velocity, and turbulence,
the granulation attractor shows a high level of structuring. By means
of the time-lag and correlation integral methods applied to the Doppler
velocities we found (i) that the granulation attractor can indeed be
described by only three variables and (ii) that its dimension seems to
depend on the appearance of enhanced shear flow (shear turbulence) at
the granular borders. This means that the dynamical system underlying
the large scale granulation is a low dimension attractor. The time-lag
and correlation integral methods enable us also to decide between
noise and signal: in the case of pure noise the method does not
converge. We found that the residual velocity associated with the
small sub-granular scales does converge, however, in higher than 10
embedding dimensions. This implies that for small scale variations
the underlying attractor is not a low dimension one.
Title: An Old Bipolar Shell Associated with η Carinae
Authors: Bohigas, J.; Tapia, M.; Ruiz, M. T.; Roth, M.
Bibcode: 2000RMxAC...9R.343B
Altcode:
Continuum subtracted dereddened images in several emission lines reveal
the existence of an extended bipolar shell around η Carinae. It is
best seen in the light of [ion{O}{3}]5007. The geometrical disposition
and mass of the shell-between 5 and 7 Modot-suggest that it
was produced by mass outflows from this star. The approximate size and
dynamic age of the bipolar shell are 100 × 45 arcsec (1.3 × 0.5 pc)
and 13000/V7 yr, where V7 is the mean expansion
velocity in 100 km s-1. Spectroscopic observations show
that the bipolar shell is mildly excited, photoionized and composed
of material that has not been through nuclear processing. Several
nitrogen-rich knots, obviously made of material that has been through
the CNO cycle, were also discovered. These are between 64 and 100
arcsec away from η Carinae, which implies that they were either
ejected at approximately the same time as the Homunculus (during the
~ 1840 brightening of this star) but with much larger velocities,
or centuries before this event. The bipolar shell and the distant
nitrogen-rich knots should provide important clues regarding the
time elapsed between the last pre-LBV and the first LBV eruption of
η Carinae, as well as on the dynamics of mass ejections from this
object. This information can be consequential in the understanding of
the last evolutionary stages of the most massive stars. A full account
of this work can be found in Bohigas et al. (2000; MNRAS, 312, 295)
Title: Solar Oscillation Transitions in Time-Dependent Perturbation
Theory
Authors: Roth, M.; Stix, M.
Bibcode: 2000SPD....31.0110R
Altcode: 2000BAAS...32..803R
Time-dependent and stationary velocity fields in the solar convection
zone lead to coupling of solar oscillations, which result in
splittings of the degenerate p-mode frequencies into multiplets. These
splittings are antisymmetric in the case of differential rotation,
i.e., pure toroidal fields, and asymmetric in the case of overturning
convection cells, i.e., poloidal fields. The reason for these effects
are intermixtures of the p-mode eigenfunctions expressed in a linear
expansion of the coupling unperturbed eigenstates. In analogy to a
perturbed quantum-mechanical system of discrete eigenstates, where the
squares of the expansion coefficients are related to the transition
probability between the states, we use time-dependent perturbation
theory to derive an expression for the expansion coefficients of the
p-mode coupling. There the square of the coefficients is regarded
as energy distribution of the perturbed sytem. We conclude that a
time-dependent velocity field has not only effects on the p-mode
splitting, but has also influence on the lifetime and therefore the
linewidth of the power spectra.
Title: Supernova 2000ca in ESO 383-32
Authors: Maza, J.; Hamuy, M.; Antezana, R.; Gonzalez, L.; Zuniga,
A.; Roth, M.
Bibcode: 2000IAUC.7409....3M
Altcode: 2000IAUC.7409R...1M; 2000IAUC.7409S...1M
J. Maza, University of Chile; and M. Hamuy, University of Arizona,
report the discovery by R. Antezana, on a 30-min unfiltered T-Max
400 film taken by L. Gonzalez on Apr. 28.18 UT with the University of
Chile's Maksutov telescope, of an apparent supernova (m_pv about 16.0)
located at R.A. = 13h35m22s.98, Decl. = -34o09'37".0 (equinox 2000.0),
which is 0".6 east and 4".7 north of the nucleus of ESO 383-32 (z
= 0.024). SN 2000ca was confirmed by Hamuy and A. Zuniga from BVRI
images taken with the Cerro Tololo 0.9-m telescope on Apr. 29.27, and
by M. Roth from JHK images taken with the Las Campanas 1.02-m Swope
telescope on Apr. 29.3. From these images, estimated magnitudes for SN
2000ca are B = 15.91 +/- 0.05, V = 15.99 +/- 0.05, which suggests that
the supernova is in an early stage. A T-Max film taken on Apr. 7.263
showed nothing at the position of the new object (limiting mag about
19.0).
Title: Near-infrared photometry of isolated spirals with and without
an AGN. I. The data
Authors: Márquez, I.; Durret, F.; González Delgado, R. M.; Marrero,
I.; Masegosa, J.; Maza, J.; Moles, M.; Pérez, E.; Roth, M.
Bibcode: 1999A&AS..140....1M
Altcode: 1999astro.ph..9351M
We present infrared imaging data in the J and K' bands obtained for
18 active spiral galaxies, together with 11 non active galaxies taken
as a control sample. All of them were chosen to satisfy well defined
isolation criteria so that the observed properties are not related to
gravitational interaction. For each object we give: the image in the K'
band, the sharp-divided image (obtained by dividing the observed image
by a filtered one), the difference image (obtained by subtracting a
model to the observed one), the color J-K' image, the ellipticity and
position angle profiles, the surface brightness profiles in J and K',
their fits by bulge+disk models and the color gradient. We have found
that four (one) active (control) galaxies previously classified as
non-barred turn out to have bars when observed in the near-infrared. One
of these four galaxies (UGC 1395) also harbours a secondary bar. For 15
(9 active, 6 control) out of 24 (14 active, 10 control) of the optically
classified barred galaxies (SB or SX) we find that a secondary bar (or
a disk, a lense or an elongated ring) is present. The work presented
here is part of a large program (DEGAS) aimed at finding out whether
there are differences between active and non active galaxies in the
properties of their central regions that could be connected with the
onset of nuclear activity. Based on data obtained at: the European
Southern Observatory, La Silla, Chile, the Télescope Bernard Lyot,
Calar Alto Observatory, Las Campanas Observatory. Also based on
observations made with the NASA/ESA Hubble Space Telescope, obtained
from the data archive at the Space Telescope Institute. Figures 1-35
are only available in electronic form at the http://www.edpsciences.org
Title: Coupling of solar p modes: quasi-degenerate perturbation theory
Authors: Roth, M.; Stix, M.
Bibcode: 1999A&A...351.1133R
Altcode:
The interaction of a large-scale stationary poloidal velocity field
(as a simple model for possibly existing giant cells) with solar p-mode
oscillations is described by quasi-degenerate perturbation theory,
as proposed by Lavely & Ritzwoller (1992). For oscillations of low
degree (l <= 12) and sectoral velocity fields we obtain numerical
solutions of the eigenvalue problem, and derive an approximate formula
for the ensuing frequency splitting. The coupling of the oscillation
modes leads to asymmetric frequency multiplets, with splittings of up to
~ 100 nHz for a velocity with amplitude v = 100 m s-1. The
splitting scales with v2, with the oscillation frequency
itself, and with the inverse difference of the squared frequencies
of the coupling partners. Possible observable effects are briefly
discussed.
Title: The hidden past of Sakurai's object. Stellar properties before
the final helium flash
Authors: Kerber, F.; Köppen, J.; Roth, M.; Trager, S. C.
Bibcode: 1999A&A...344L..79K
Altcode:
We derive the properties of Sakurai's object before its sudden
evolutionary change by studying the remnant ionization of the old
planetary nebula (PN) surrounding it. The star must have had a
surface temperature of 98 000 +/- 7000 K (95 000 +/- 7000 K). For
a distance of 1.5 kpc (5.5 kpc) the luminosity should have been 25
+/- 5 Lsun (240 +/- 40 Lsun). The central star
thus was highly evolved and had already reached the tip of the white
dwarf cooling track. Sakurai's object indeed is an example of a star
undergoing a very late helium flash.
Title: Chapter 5-Plasma Transfer Processes at the Magnetopause
Authors: Sibeck, D. G.; Paschmann, G.; Treumann, R. A.; Fuselier,
S. A.; Lennartsson, W.; Lockwood, M.; Lundin, R.; Ogilvie, K. W.;
Onsager, T. G.; Phan, T. -D.; Roth, M.; Scholer, M.; Sckopke, N.;
Stasiewicz, K.; Yamauchi, M.
Bibcode: 1999SSRv...88..207S
Altcode:
No abstract at ADS
Title: Resonant amplification of MHD waves in realistic subsolar
magnetopause configurations
Authors: De Keyser, J.; Roth, M.; Reberac, F.; Rezeau, L.; Belmont, G.
Bibcode: 1999JGR...104.2399D
Altcode:
Broadband ULF fluctuations are routinely observed throughout the
magnetosheath; the fluctuation level peaks at the magnetopause and
becomes very small in the magnetosphere. The present paper analyzes the
propagation of magnetosheath waves and the transport of energy at the
subsolar magnetopause by means of a linear perturbation analysis in
the limit of the MHD approximation. We examine realistic equilibrium
magnetopause configurations with a cold and dense magnetosheath
and a hot, tenuous magnetosphere, possibly including a trapped
magnetopause population. The effects of magnetic field rotation are
examined. Resonant amplification of monochromatic magnetosonic waves
at the magnetopause is found to occur under various conditions. For
a given frequency, several field lines inside the magnetopause layer
can resonate simultaneously.
Title: Coupling of Solar Oscillations in Quasi-Degenerate Perturbation
Theory
Authors: Roth, M.; Stix, M.
Bibcode: 1999AGAb...15...92R
Altcode: 1999AGM....15..P11R
We investigate the coupling of the solar p-modes, caused by a
stationary poloidal velocity field in the solar convection zone,
via quasi-degenerate perturbation theory, as suggested by Lavely and
Ritzwoller (Phil. Trans. R. Soc. Lond. A (1992) 339, 431-496). As a
consequence of the Wigner-Eckhart theorem oscillations couple if they
satisfy several selection rules. The result is the lifting of the
degeneracy. But in contrast to the rotational splitting, coupling
between different multiplets is possible leading to asymmetric
frequency multiplets. For illustration we examine the effect of
sectoral velocity fields, similar to giant convective cells. We find
an approximate solution of the general equations for the coupling of
two p-modes with a degree l <= 12. The individual frequency shifts
scale with the frequency itself, with the square of the velocity,
and with the inverse difference of the squared frequencies of the two
involved modes. The relative deviation of this estimate from the exact
result is less than 10 %. Finally, we show that the splittings are up
to ~100 nHz for a velocity with amplitude 100 m/s. Hence, large scale
poloidal velocity fields lead to an additional line broadening and to
an asymmetric line profile in the power spectra.
Title: Deep Near-Infrared Images and ISOCAM Observations of Chamaeleon
I North
Authors: Persi, P.; Marenzi, A. R.; Kaas, A. A.; Olofsson, G.; Nordh,
L.; Roth, M.
Bibcode: 1999AJ....117..439P
Altcode:
We present the results of deep near-infrared imaging and ISOCAM
observations of three selected regions localized in the northern part of
the Chamaeleon I dark cloud, in order to search for the low-luminosity
population. In an area of 3x3 arcmin^2 centered on the bipolar molecular
outflow, which is the densest part of the cloud, we have discovered
a new Class I source (here named ISOCAM-Cha INa2) with a spectral
index alpha = 1.9 and 1-18 μm luminosity of 0.6 L_solar that is
most probably responsible for the observed CO outflow. The comparison
between the observed K-magnitude distribution for this region and that
obtained for a region outside the outflow and adjacent to the star HD
97300 indicates the possible presence of a very low luminosity young
stellar population in the densest part of the cloud.
Title: Granulation and its variation with time
Authors: Nesis, A.; Hammer, R.; Roth, M.; Schleicher, H.
Bibcode: 1999AGAb...15...89N
Altcode: 1999AGM....15..P04N
The velocity fields on the solar surface are influenced by large
granules. They are stochastic events of convective origin which affect
the dynamics of the solar layers in various ways, for example, by
shear flow. Shear flows on the other hand produce turbulence, and thus
turbulent pressure is capable of back reacting upon the convection. This
leads to three principal questions: Is there a characteristic time
associated with the decay of the granular velocity amplitudes? What
is the nature of the attenuation of the velocity with time? What
interactions take place with the local oscillations? These questions
will be addressed through the discussion of spectrograph observations
made at the VTT.
Title: A New System of Faint Near-Infrared Standard Stars
Authors: Persson, S. E.; Murphy, D. C.; Krzeminski, W.; Roth, M.;
Rieke, M. J.
Bibcode: 1998AJ....116.2475P
Altcode:
A new grid of 65 faint near-infrared standard stars is presented. They
are spread around the sky, lie between 10th and 12th magnitude at K,
and are measured in most cases to precisions better than 0.001 mag
in the J, H, K, and K_s bands; the latter is a medium-band modified
K. A secondary list of red stars suitable for determining color
transformations between photometric systems is also presented.
Title: The interstellar medium around the SNR G18.8+0.3
Authors: Giacani, E.; Reynoso, E.; Dubner, G.; Roth, M.
Bibcode: 1998larm.confE..91G
Altcode:
The morphology and dynamics of supernova remnants (SNRs) appear
to be strongly affected by the ambient circumstellar medium (CMS)
as well as the interstellar medium (ISM). The study of the environs
through atomic and/or molecular lines provides a three-dimensional
picture of the medium into which a SNR expands. This information is
crucial in understanding the characteristics of SNRs as observed in
the different spectral bands, helping to disentangle the intrinsic
and extrinsic factors which modify the morphology of SNRs. The aim of
the present project is to investigate the distribution of the neutral
hydrogen and the carbon monoxide in direction to the SNR G18.8+0.3
(Kes 67), in search for signatures that allow to disclose the role of
the surrounding gas in the evolution of this remnant. To obtain the HI
21 cm images, a field of 2.5deg X 1.5deg around G18.8+0.3 was observed
with an angular resolution of 14'.7 using the 64 m antenna at Parkes
(Australia) in June 1995. The 12CO (J:0->1) and 13CO (J:0->1)
data were obtained with the Nagoya University (Japan) 4 m antenna at
Las Campanas (Chile). The angular resolution is 2'.7. Three fields
(increasingly larger) were surveyed: the first toward the eastern bump
of the shell, with a sampling of 2'; the second, covering the continuum
shell and its immediate neighbourhood , with a sampling of 4'; and
the third one, covering a larger area centered in the remnant, with a
sampling of 8'. From the analysis of the HI 21 cm line data in the whole
observed velocity interval, we find the existence of neutral gas likely
to be associated with the SNR in the range +15 to +22 km/s . In this
interval, the HI emission appears clearly distorted, surrounding the
more flattened and brightest sides of the radio continuum source. The
study of the CO distribution in the region shows that the molecular
gas probably associated with G18.8+0.3 consists of a series of clouds
forming an incomplete loop surrounding the most intense parts of the
radio shell. This chain of clouds is detected from +10 km/s at the
northeast, to +23 km/s at the south. The most conspicuous CO emission
features are: a cloud which perfectly matches the northeastern edge
of the SNR; a small concentration coinciding with a radio continuum
indentation; and an elongated cloud to the southeast, which bends
following the shape of the SNR's shell. Based on the above results,
we estimate the systemic velocity of the SNR to be ~ +16 km/s ,
which produces a kinematic distance of about 1.8 kpc, according to the
galactic rotation model by Fitch et al. (1989). The correlation between
the flattest, most intense regions of the radio shell, with the most
dense concentrations in the ISM, are a strong evidence of the medium
having influenced the evolution of this SNR. Physical parameters of
the associated gas are estimated.
Title: A compact detector for the measurement of the cosmic-ray muon
charge ratio.
Authors: Vulpescu, B.; Wentz, J.; Brancus, I. M.; Rebel, H.; Badea,
A. F.; Bozdog, H.; Duma, M.; Haungs, A.; Mathes, H. -J.; Petcu, M.;
Roth, M.
Bibcode: 1998NIMPA.414..205V
Altcode:
A compact sampling calorimeter is developed and used to measure the
ratio between positive and negative muons in the cosmic-ray flux at
momenta below 1 GeV/c. The delayed coincidence method is used, based on
the reduced mean lifetime of negative muons due to nuclear capture in
matter. It is shown that aluminum is a good choice as a capture medium
for negative muons and suitable for a simple detector set-up. The muon
charge ratio is found to be 1.30±0.05 for a mean momentum of 0.86
GeV/c and over a zenith angle acceptance with Θmean = 26°.
Title: Flow shear across solar wind discontinuities: WIND observations
Authors: De Keyser, J.; Roth, M.; Söding, A.
Bibcode: 1998GeoRL..25.2649D
Altcode:
We examine the tangential magnetic field and velocity shears
across directional discontinuities (DDs) with significant change in
magnetic field intensity observed by WIND in slow and fast solar wind
streams. The magnetic field rotation sense in fast wind DDs is that
predicted by theory for outward propagating rotational discontinuities
(RDs), but flow shear magnitude and orientation do not always satisfy
RD theory. Alternatively, DDs with small normal magnetic field can
be regarded as tangential discontinuities (TDs); the observed shears
imply that the length scale over which the proton velocity distribution
changes at the discontinuity can be both smaller or larger than that
of the electron distribution. The slow wind includes a larger fraction
of DDs that disagree with RD theory. It is shown that the flow shear
orientations allowed in a TD provide a continuous transition between
the opposite orientations for RDs propagating along or against the
magnetic field direction.
Title: New evolved planetary nebulae in the southern hemisphere
Authors: Kerber, F.; Roth, M.; Manchado, A.; Groebner, H.
Bibcode: 1998A&AS..130..501K
Altcode:
The major purpose of this paper is to investigate the nature of
planetary nebulae (PNe) candidates in the southern hemisphere, taken
from an internal list. We present spectroscopic observations and
imaging of six PNe identified for the first time. Another candidate
turned out to be a galaxy. All observed PNe represent evolved stages,
their angular diameter ranging from 15arcsec to 120arcsec , and exhibit
very low surface brightnesses. For three PNe indications of interaction
with the interstellar medium (ISM) has been discovered.
Title: The magnetospheric driver of subauroral ion drifts
Authors: De Keyser, J.; Roth, M.; Lemaire, J.
Bibcode: 1998GeoRL..25.1625D
Altcode:
Subauroral ion drifts (SAID) are narrow layers of intense westward
ionospheric flow observed during substorms. We present numerical
simulations showing that the combined effect of thermo-electric and
convection electric fields in a magnetospheric current sheet—when
mapped down to the ionosphere—can account for the westward direction
of the ion drift, the width and intensity of the drift speed peak,
and the lifetime of SAID. The model can also explain why SAID occur
mainly in the pre-midnight sector.
Title: Electron density at the subsolar magnetopause for high magnetic
shear: ISEE 1 and 2 observations
Authors: Hubert, D.; Harvey, C. C.; Roth, M.; De Keyser, J.
Bibcode: 1998JGR...103.6685H
Altcode:
The ISEE radio wave propagation electron density experiment allowed the
determination of the integrated electron density between the ISEE 1 and
ISEE 2 satellites at the relatively high rate of 8 or 32 Hz. When the
component of the spacecraft separation vector in the direction of the
normal to the magnetopause is significantly smaller than the thickness
of the current layer, this data set allows the internal structure
of the magnetopause to be studied and compared with theoretical
predictions. For a particular triple subsolar magnetopause crossing
with high magnetic shear, an electron density overshoot is observed
in the current layer adjacent to the magnetosheath. The similarity
of the three crossings indicates that the internal structure of the
magnetopause does not change dramatically during the time interval
considered. A superposed epoch analysis of these crossings is consistent
with the density profile obtained from kinetic simulations. The general
relationship between magnetic field asymmetry, magnetic field rotation
angle and electron density overshoot is discussed. It is concluded
that a density overshoot could be a typical feature of the subsolar
magnetopause with high magnetic shear. This conclusion is supported by
two other dayside magnetopause crossings for which high time resolution
electron density data are available.
Title: Guided waves in near-surface seismic surveys
Authors: Roth, M.; Holliger, K.; Green, A. G.
Bibcode: 1998GeoRL..25.1071R
Altcode:
Much of the Earth's surface is covered by a thin blanket of
unconsolidated sediments or weathered bedrock. Boundaries within or
at the base of this surficial layer (e.g. watertable, bedrock surface,
transition to unweathered rock) are commonly associated with a strong
seismic contrast. Layers contained between the surface and shallowest
boundaries may be efficient waveguides and, as such, associated with
significant source-generated seismic noise. Whereas Rayleigh waves
(groundroll) can be described in terms of normal modes, we demonstrate
that the faster shingled guided waves can be explained in terms of
leaking modes. Due to the relatively high Poisson's ratios in the
shallow subsurface, guided waves are composed dominantly of multiply
reflected P-waves. We compare our results with those obtained using
a conventional acoustic waveguide approximation and discuss methods
for extracting information from guided waves for geotechnical and
environmental applications.
Title: Magnetic field rotation at the dayside magnetopause: AMPTE/IRM
observations
Authors: De Keyser, J.; Roth, M.
Bibcode: 1998JGR...103.6663D
Altcode:
Given the large-scale magnetosheath flow pattern around the
magnetosphere, the tangential discontinuity magnetopause model of De
Keyser and Roth predicts, for a prescribed magnetic field rotation
angle and rotation sense, where equilibrium is possible on the dayside
magnetopause surface and where it is not. In this paper we verify
these predictions using 5 s time resolution magnetic field and plasma
observations of the low-latitude dayside magnetospheric boundary
acquired by the Active Magnetospheric Particle Tracer Explorers/Ion
Release Module satellite. The model is confirmed by (1) the dominant
presence of large positive magnetic field rotations among the dawnside
crossings north of the equator, (2) the observation of positive and
negative rotations near the stagnation point and at the duskside, and
(3) the rare occurrence and questionable tangential discontinuity nature
of low magnetic shear dawnside crossings. The absence of tangential
discontinuity equilibrium in dawnside low shear crossings is consistent
with the observation of increased dawnside low-latitude boundary layer
thickness for northward magnetosheath field reported in the literature.
Title: Equilibrium conditions and magnetic field rotation at the
tangential discontinuity magnetopause
Authors: De Keyser, J.; Roth, M.
Bibcode: 1998JGR...103.6653D
Altcode:
De Keyser and Roth recently have developed a kinetic model of the
tangential discontinuity magnetopause. This model predicts (1) that not
all configurations of magnetic field vectors and magnetosheath velocity
allow an equilibrium to exist and (2) that there is a preference for
a particular magnetic field rotation sense across the magnetopause
due to the different response of ions and electrons to the electric
field in the current layer. In the present paper we extend the original
model to allow for different magnetospheric and magnetosheath densities
and temperatures, and we show that the conclusions remain essentially
unchanged. Given the large-scale magnetosheath flow pattern around the
magnetosphere, we also compute which regions of the dayside magnetopause
may be in tangential discontinuity equilibrium for a given magnetosheath
field orientation.
Title: High altitude electrostatic fields driving subauroral ion
drifts
Authors: Lemaire, J. F.; Roth, M.; De Keyser, J.
Bibcode: 1998mrat.conf...61L
Altcode:
A subauroral ion drift (SAID) layer is characterised by a narrow peak of
westward ion drift speed exceeding 1000 m/s. It is confined in less than
1 degree in latitude and located equatorward of the nightside auroral
zone but poleward of the plasmapause. We propose a mechanism for the
narrow peak electric field driving this phenomenon: an electrostatic
potential is produced by thermo-electric charge separation across
the front edge of a hot plasma cloud moving inward from the tail and
penetrating into the colder background plasma in the plasmatrough and
at the plasmapause. Quantitative calculations corroborate this scenario.
Title: Sakurai's Object, a Late He-Flash
Authors: Kerber, F.; Gratl, H.; Kimeswenger, S.; Roth, M.
Bibcode: 1998HiA....11..361K
Altcode:
No abstract at ADS
Title: The charge ratio of cosmic ray muons.
Authors: Brancus, I. M.; Vulpescu, B.; Wentz, J.; Rebel, H.; Badea,
A. F.; Bozdog, H.; Duma, M.; Haungs, A.; Mathes, H. -J.; Petcu, M.;
Roth, M.
Bibcode: 1998ctcr.conf..121B
Altcode:
The aspects of the measurements of the muon charge ratio, in particular
at low energies, are illustrated by a recent experimental study using
an improved "delayed coincidence" method with a compact sampling
calorimeter. Using the CORSIKA program for the simulation of extended
air showers, the muon energy spectrum and the charge ratio have
been investigated and compared with experimental data in the range
<1000 GeV.
Title: Multi-Spacecraft Validation of a Current Sheet Model
Authors: de Keyser, J.; Roth, M.
Bibcode: 1997ESASP.415...75D
Altcode: 1997cpsh.conf...75D
No abstract at ADS
Title: Sub-arcsec resolution infrared images of the star forming
region G 35.20-1.74.
Authors: Persi, P.; Felli, M.; Lagage, P. O.; Roth, M.; Testi, L.
Bibcode: 1997A&A...327..299P
Altcode:
We present J(1.25μm), H(1.65μm), K(2.2μm), H_2_(2.125μm) and 11.2μm
infrared images at sub-arcsec resolution of an area centered around the
star forming region G 35.20-1.74. In J, H and K a cluster of early type
stellar sources with infrared excess clearly stands out with respect to
the background distribution and is associated with a diffuse K emission
around an UC HII region (which is the brightest source at K). No H_2_
emission is detected in narrow-band images at 2.125μm. At 11.2μm
six components are detected. The brightest one (MIR3) is extended and
coincides with the UC HII region. The source with steepest IR spectrum
and the largest infrared excess (MIR1) is associated with an H_2_O
maser and a near IR source detected only at K. It is separated from
the IR cluster and at a distance of 20'' from the UC HII region. The
IR emission comes from a local young stellar object (YSO) associated
with the maser. The lack of radio continuum emission from MIR1 confirms
that H_2_O masers can trace the youngest evolutionary stages of massive
YSOs, much before the appearance of a radio UC HII region and shows that
star formation is not limited to the IR cluster (where most probably
it has already come to an end) but is still taking place in other
parts of the molecular cloud. Of the other 11.2μm sources, three
(MIR2, MIR4 and MIR5) present IR excesses and are similar to MIR1,
while MIR6 appears to be a reddened early-type star. The morphology of
the entire star forming complex, taking into account also molecular
and sub-mm observations, is indicative of different and independent
episodes of star formation taking place in the same molecular cloud.
Title: Scientific Sounding Rocket and Balloon Activities in Germany
Authors: Röhrig, O.; Roth, M.
Bibcode: 1997ESASP.397...17R
Altcode: 1997erbp.conf...17R
No abstract at ADS
Title: Erratum: ``Equilibrium conditions for the tangential
discontinuity magnetopause'' [Journal of Geophysical Research, 102,
9513-9530 (1997)]
Authors: De Keyser, J.; Roth, M.
Bibcode: 1997JGR...10219943D
Altcode:
No abstract at ADS
Title: Near Infrared Imaging of Abell 30
Authors: Kimeswenger, S.; Kerber, F.; Roth, M.
Bibcode: 1997AGAb...13..227K
Altcode:
No abstract at ADS
Title: Solar wind velocity jumps across tangential discontinuities:
ULYSSES observations and kinetic interpretation
Authors: de Keyser, J.; Roth, M.; Tsurutani, B. T.; Ho, C. M.;
Phillips, J. L.
Bibcode: 1997A&A...321..945D
Altcode:
Some tangential discontinuities (TDs) observed by the Ulysses
spacecraft interface solar wind regions that differ only in their
bulk velocity and magnetic field orientation; composition, density,
temperature and magnetic field intensity are essentially the same in
both regions. The relation between the plasma velocity jump across
the TD and the magnetic field is investigated through the analysis and
simulation of equilibrium plane TD configurations. These theoretical
results are compared with Ulysses observations. It is concluded that
(a) the theoretically predicted magnetic field profile agrees with
the morphology of the observed profile, (b) solar wind transitions
are essentially of mixed type, i.e. both ion and electron velocity
distribution functions are non-Maxwellian inside the transition layer,
(c) there are constraints on the orientation and magnitude of the
velocity jump that can be supported across a single transition, (d)
large magnetic field rotations correspond to wide transition layers, and
(e) in addition to density and temperature inhomogeneities, variations
in the bulk velocity are a major reason for the solar wind plasma to
set up current-carrying boundary layers.
Title: Equilibrium conditions for the tangential discontinuity
magnetopause
Authors: De Keyser, J.; Roth, M.
Bibcode: 1997JGR...102.9513D
Altcode:
Early satellite observations of the dayside magnetopause have
suggested that the magnetic field typically rotates clockwise above
the solar-magnetospheric equatorial plane and counterclockwise
below it, in agreement with the predictions of first-order orbit
theory for magnetopause crossings of the rotational discontinuity
type. The present paper treats the tangential discontinuity (TD)
case. The influence of magnetosheath magnetic field and plasma flow
on the magnetopause equilibrium structure is analyzed by means of
a Vlasov model. The nature of the current layer plays a major role;
the analysis is carried out for ion-dominated, electron-dominated, and
mixed layers. Necessary and sufficient conditions for the existence
of an equilibrium magnetopause are derived. It is found that (1)
the magnetopause is best modeled as a transition layer of mixed
type; (2) for high magnetic shear the magnetic field at the dayside
magnetopause preferentially rotates clockwise above the equatorial
plane and counterclockwise below it, while it rotates counterclockwise
above and clockwise below the equatorial plane at the tail flanks; this
effect becomes more manifest as the magnetosheath flow is faster and
as the difference in proton and electron transition lengths is more
pronounced; (3) for low magnetic shear, TD equilibrium is expected
to be lost more easily at the dawnside than at the duskside; and (4)
the model provides a magnetopause thickness estimate; in particular,
the low magnetic shear dawn magnetopause is predicted to be thinner
than the dusk magnetopause.
Title: Novalike Variable in Sagittarius
Authors: Kerber, F.; Gratl, H.; Roth, M.; Sakurai, Y.
Bibcode: 1997IAUC.6601....2K
Altcode: 1997IAUC.6601R...1K
F. Kerber and H. Gratl, University of Innsbruck; and M. Roth, Las
Campanas Observatory, report: "We have found dramatic changes in the
spectrum of the novalike object reported by Y. Sakurai in Feb. 1996
(cf. IAUC 6322, 6323) at R.A. = 17h52m32s.69, Decl. = -17d41'07".7
(equinox 2000.0), compared to our observations from one year ago. The
object was suspected to be undergoing a late He-flash (IAUC 6325,
6328), and our group has been monitoring the object's evolution since
discovery. Spectra obtained on 1997 Mar. 23.33 UT at the 2.5-m du Pont
telescope show very prominent lines in the C2 Swan bands (bandheads
473, 516 and 558 nm) not seen before. In addition, the H Balmer lines
seem to have weakened considerably compared to a year ago. The object
was expected to change quickly in astronomical terms, but the observed
change is certainly much faster and much more massive than expected."
Title: Ulysse à la découverte des régions polaires du Soleil. I. Un
projet hors du commun.
Authors: Roth, M.
Bibcode: 1997C&T...113...19R
Altcode:
No abstract at ADS
Title: The ground-based leg for our ISO PNe: NIR-imaging
Authors: Kimeswenger, S.; Kerber, F.; Kienel, C.; Roth, M.
Bibcode: 1997IAUS..180..249K
Altcode:
No abstract at ADS
Title: The ground based leg for our ISO PNe: Spectroscopy
Authors: Kerber, F.; Koberl, T.; Gratl, H.; Roth, M.
Bibcode: 1997IAUS..180..246K
Altcode:
No abstract at ADS
Title: Spectroscopy of new faint Planetary Nebulae
Authors: Kerber, F.; Grobner, H.; Weinberger, R.; Roth, M.
Bibcode: 1997IAUS..180...22K
Altcode:
No abstract at ADS
Title: A late He-flash just in time for ISO?
Authors: Kerber, F.; Gratl, H.; Kimeswenger, S.; Weinberger, R.;
Roth, M.; Duffee, B.
Bibcode: 1997IAUS..180..390K
Altcode:
No abstract at ADS
Title: The embedded stellar population in northern NGC 6334.
Authors: Tapia, M.; Persi, P.; Roth, M.
Bibcode: 1996A&A...316..102T
Altcode:
JHK imaging photometry is reported of an area of approximately 2'x3'
centred on the far infrared source NGC 6334 I with limiting magnitudes
J=18.3, H=17.8 and K=16.2. More than 224 sources were detected in
K-band, increasing by a factor of more than seven the number of
objects found in previous near-IR surveys. Most of the sources are
located in an area of about 3500 square arcsec centered around the
massive young stellar object Irs1, which ionizes the compact HII
region NGC 6334 F. The location of these sources and the analysis of
the colour-colour and colour-magnitude diagrams suggest the presence
of an embedded and young stellar cluster of size ~70" (0.6pc), and
stellar density of about 1200pc^-3^. The star formation efficiency
is estimated to be SFE=~0.25. Only a few of the most luminous stars
of the cluster were found to show large near-IR excesses but this
may be due to the non-detection, at the shortest wavelength, of the
majority of the highly reddened cluster members. The extinction of the
region is very variable with a maximum of A_V_>70 in Irs2 while the
average is <A_V_>=~40. Very close to the position of an H_2_O
maser associated with NGC 6334 I(N), a contracting core at an earlier
evolutionary stage, we found six very red sources, one of which is a
small and diffuse nebula seen only at 2.2μm. Finally, the older and
developed HII region NGC 6334 E was found to be probably ionized by
a small cluster of at least 12 B0-B0.5 ZAMS stars.
Title: NGC 2477: Photometry and luminosity function.
Authors: Galaz, G.; Ruiz, M. T.; Thompson, I.; Roth, M.
Bibcode: 1996A&AS..119..413G
Altcode:
Trough photometric methods we have constructed the luminosity function
for the southern open cluster NGC 2477 down to M_v_=~12. We present
R-I color-magnitude diagrams and near-infrared color-color diagrams,
which allow us to separate statistically the cluster stars from
the field ones, numerous because of the galactic latitude of the
cluster. Our luminosity function (LF) reproduces some features obtained
by other authors, namely, a dip at M_v_=~7, and a probable maximum at
M_v_=~12. The method developed to separate cluster stars from field
stars could be of interest to other astronomical problems.
Title: Theoretical Plasma Distributions Consistent with ULYSSES
Magnetic Field Observations in a Solar Wind Tangential Discontinuity
Authors: De Keyser, J.; Roth, M.; Lemaire, J.; Tsurutani, B. T.; Ho,
C. M.; Hammond, C. M.
Bibcode: 1996SoPh..166..415D
Altcode:
The overall multi-layer structure of the magnetic field profile observed
by Ulysses across a broad solar wind tangential discontinuity can be
reproduced fairly well by means of a kinetic model. Such a simulation
provides complementary information about the velocity distribution
functions, which are not always available from the plasma experiment
due to the low time resolution inherent in plasma measurements. The
success of such a simulation proves that the kinetic model can be
used as a realistic basis for further studies of the structure and
stability of solar wind tangential discontinuities.
Title: Vlasov Theory of the Equilibrium Structure of Tangential
Discontinuities in Space Plasmas
Authors: Roth, M.; de Keyser, J.; Kuznetsova, M. M.
Bibcode: 1996SSRv...76..251R
Altcode:
Extensive theoretical work has been performed on the equilibrium
structure of tangential discontinuities (TDs) in collisionless
plasmas. This paper reviews kinetic models based on steady-state
solutions of the Vlasov equation. It is shown that most of the existing
models are special cases of a generalized multi-species model. In
this generalized model all particle populations -from both outer
regions and from inside the layer — are described using a unique
formalism for the velocity distribution functions. Because of their
historical importance, the Harris and Sestero models are reviewed and
deduced from the generalized model. The Lee and Kan model is also a
special case of the generalized model. The generalized model, however,
is also able to describe TDs with velocity shear and large angles
of magnetic field rotation. Such a multi-species model with a large
number of free parameters and different gradient scales illustrates
many observable features of TDs, including their multiscale fine
structure. Particular attention is paid to the magnetopause. Observed
magnetopause crossings are simulated. The effects of the relative flow
velocity and asymmetrical magnetic field profiles on the structure
of the magnetopause and on its stability with respect to tearing
perturbations are discussed. We also present calculations that
demonstrate the potential of the generalized model in explaining
the origin of discrete auroral arcs. Numerical simulations of solar
wind TDs with heavy ions and a large spectrum of thicknesses are also
feasible. This indicates that such a model is of fundamental importance
for understanding the detailed structure of solar wind TDs, like
those observed by the interplanetary spacecraft ULYSSES. The problems
associated with the one-dimensional, time-independent Vlasov approach
are discussed and a variational principle is suggested to reduce the
arbitrariness resulting from the large number of free parameters.
Title: Shocked molecular hydrogen emission in the bipolar outflow
NGC 6334 I.
Authors: Persi, P.; Roth, M.; Tapia, M.; Marenzi, A. R.; Felli, M.;
Testi, L.; Ferrari-Toniolo, M.
Bibcode: 1996A&A...307..591P
Altcode:
Sub-arcsec images in the J,H,K and H_2_ and nearby continuum of
the bipolar outflow NGC 6334 I are presented. Three knots of H_2_
emission are found which coincide with recently discovered NH_3_(3,3)
masers. Two of these are aligned along the CO bipolar outflow,
indicating that the hydrogen molecular emission is shock excited. We
have also detected a loop-shaped infrared nebula extending to the
east of the massive mid-infrared source IRS1 which illuminates the
reflection nebula. IRS1 consists of at least four components in the
near-infrared. The interaction of the stellar wind from these young
stellar objects with the surrounding medium could excite the third H_2_
emission knot and associated ammonia maser.
Title: Ray tracing in random media
Authors: Witte, O.; Roth, M.; Müller, G.
Bibcode: 1996GeoJI.124..159W
Altcode:
No abstract at ADS
Title: Hannes Alfvén (1908 - 1995): géophysicien, astrophysicien
et cosmologiste.
Authors: Roth, M.; Lemaire, J.
Bibcode: 1995C&T...111...67R
Altcode:
No abstract at ADS
Title: JHK Imaging Photometry of TR 14, TR 15 and TR 16
Authors: Roth, M.; Tapia, R.; Vazquez, R. A.; Feinstein, A.
Bibcode: 1995RMxAC...2...93R
Altcode:
No abstract at ADS
Title: UBVRI Imaging Photometry of the ETA~ Arinae Region
Authors: Tapia, M.; Roth, M.; Vazquez, R. A.; Feinstein, A.
Bibcode: 1995RMxAC...2...71T
Altcode:
No abstract at ADS
Title: UBVRI Polarimetry of Stars in Carina Clusters
Authors: Schwarz, H. E.; Claeskens, J. -F.; Tapia, M.; Roth, M.
Bibcode: 1995RMxAC...2...69S
Altcode:
No abstract at ADS
Title: Results from the Las Campanas Program to Monitor QSO Optical
Brightness Variations
Authors: Sirola, C. J.; Turnshek, D. A.; Monier, E.; Sheaffer, S.;
Weymann, R. J.; Morris, S.; Duhalde, O.; Krzeminski, W.; Kunkel, W.;
Roth, M.
Bibcode: 1995AAS...186.2402S
Altcode: 1995BAAS...27S.845S
We present results from a brightness monitoring program of >
150 QSOs. Short exposures were obtained using a CCD chip on the Las
Campanas 40-inch Swope Telescope. Observations of the QSOs have been
taken several times per year from late 1987 to early 1994. Brightness
variations have been determined relative to stars contained in an ~
5 arcmin square field. The purpose of the program is to investigate
the characteristics of the brightness variations among various types
of QSOs: (1) radio-quiet QSOs with broad absorption lines (BALs),
(2) radio-quiet QSOs without BALs, and (3) radio-loud QSOs. We compute
the ensemble average structure function and autocorrelation function
of the light curves in the rest frames of the QSOs. We find no large
differences in the variability properties between the two types of
radio-quiet QSOs over time scales of <= 1.5 years (proper time in
the QSO rest frame), but we do find a substantial difference in the
variability properties of radio-quiet and radio-loud QSOs over the
same time scales.
Title: Thresholds for magnetic percolation through the magnetopause
current layer in asymmetrical magnetic fields
Authors: Kuznetsova, M. M.; Roth, M.
Bibcode: 1995JGR...100..155K
Altcode:
The Vlasov kinetic approach is used to study the stability of magnetic
surfaces with respect to spontaneous excitation of collisionless
tearing perturbations within magnetopause current layers (MCLs)
with asymmetrical magnetic field profiles. For the unperturbed
configuration a ``tractable'' (that is, with a minimum number of
free parameters) Vlasov equilibrium model describing a tangential
discontinuity is developed. In this model, asymmetrical MCLs
are not electrostatically equipotential configurations and their
structure is only determined by the angle of the magnetic field
rotation θ0 and the magnetic field asymmetry factor
κB =(B2-B1)/B2, where
B1 and B2 are the magnetic
field intensities in the adjacent magnetosheath and magnetospheric
regions, respectively. The stochastic percolation model by Galeev
et al. (1986), based on the symmetrical charge-neutral Harris
equilibrium, is generalized for asymmetrical MCLs. Asymmetry in the
B field profile strongly modifies the dependence of the marginal MCL
thickness (below which the MCL is subjected to percolation) on the
polarity of the interplanetary magnetic field (IMF). For a northward
IMF (θ0<90°), the percolation is impossible when
κB>=0.4, while for moderate values of κB
(0.15<=κB<0.4) only thin MCLs can be percolated. When
κB>0.3, the maximum thickness of MCLs subjected to
percolation is achieved for θ0>90°, that is, for a
southward IMF. Assuming that the magnetopause should, on the average,
be close to its stability threshold, realistic asymmetrical MCLs (with
κB>0.3) should be thinner for a northward IMF than for
a southward IMF.
Title: Impulsive Transport of Solar Wind into the Magnetosphere
Authors: Roth, M.
Bibcode: 1995GMS....90..343R
Altcode: 1995phma.book..343R
According to the theory of "impulsive penetration" proposed by Lemaire
and Roth, magnetosheath plasma irregularities with an excess momentum
density enter the geomagnetic field by means of an E×B drift resulting
from their self electric polarization. Collective polarization,
thermo-electric charge separation, and non-adiabatic braking are
important non-ideal MHD processes. The dipole-dipole interaction force
between the Earth's dipole field and the current system of a penetrating
3-dimensional diamagnetic plasmoid can increase or decrease the entry
velocity, depending on the orientation of the IMF. A large number of
laboratory experiments as well as significant geophysical observations
are consistent with this impulsive penetration model.
Title: Kinetic Structure of the Magnetopause: Equilibrium and
Percolation
Authors: Kuznetsova, M. M.; Roth, M.; Zelenyi, L. M.
Bibcode: 1995GMS....90...99K
Altcode: 1995phma.book...99K
The paper addresses theoretical studies of the magnetopause kinetic fine
structure. A considerable amount of effort was made beginning in the
early sixties to construct Vlasov equilibrium models of one-dimensional
tangential discontinuities which were assumed to provide a reasonable
approximation for the structure of the magnetopause current layer
(MCL). Simple models of MCLs of finite thickness (with a minimum
number of free parameters) can be used to illustrate the effects of
asymmetrical boundary conditions on the internal structure of the
current layer. One-dimensional current layers are thermodynamical
nonequilibrium systems which have an excess of free energy that
allows excitation of drift tearing modes which result in destruction
of magnetic surfaces. The stochastic wandering of magnetic field
lines between the destroyed surfaces can result in formation of
percolated magnetic filaments topologically connecting magnetosheath
and magnetospheric field lines. The stochastic percolation model by
Galeev et al. [1986], based on the symmetrical charge-neutral Harris
equilibrium, is generalized for asymmetrical MCLs. Asymmetry in the
B field profile strongly modifies the dependence of the marginal MCL
thickness (below which the MCL is subjected to percolation) on the
angle of magnetic field rotation θ0. The maximum thickness
of MCLs which still could be subjected to percolation is achieved
for θ0>90°, that is, for southward IMF. Realistic
asymmetrical MCLs are likely to be thinner for a northward IMF than for
a southward IMF. For northward IMF the MCLs are likely to be thinner
for larger values of plasma β in the magnetosheath.
Title: Near-infrared images of galactic masers I. Association between
infrared sources and masers
Authors: Testi, L.; Felli, M.; Persi, P.; Roth, M.
Bibcode: 1994A&A...288..634T
Altcode:
We present the first results of an extensive near infrared survey of
galactic H_2_O and OH masers in high-luminosity star forming regions
(SFR) aimed to see if there are near-infrared (NIR) sources directly
associated with the masers. Seventeen fields for which accurate
VLA positions of the masers were available have been imaged in the
three J, H, and K NIR broad band filters with pixel resolution of
1.34 arcsec/pixel and a field of view of roughly 3'x3'. All observed
fields show a high density of K-band sources, completely undetected in
previous surveys, probably stellar clusters located in the SFR. From
numerical simulations we find that the distributions of the observed
first-neighbour K-band source to the maser is very unlikely due to
chance coincidence with uniformly distributed field sources. For this
reason, the infrared source nearest to the maser (<~10 arcseconds)
is considered to be associated with the maser. All these sources have
distinctive characteristics: they are weak and detected only in K, or
if the H magnitude is measurable, they show an H-K colour index greater
than 2. Although not in all sources there are high sensitivity-high
resolution radio continuum observations, only few of the K-band/maser
sources are closely associated with known ultracompact (UC) HII
regions. After considering several plausible alternatives we find that
the observed NIR emission is produced by a young stellar object (YSO)
surrounded by a dusty circumstellar envelope. In the evolutionary
scheme of SFR this result places the NIR/maser sources in a stage
preceding that of UCHII regions, in which the radio continuum from
ionized gas is undetectable with present sensitivities either because
so much reduced by self-absorption or by dust absorption of stellar
UV photons in the very dense envelope of the YSO or intrinsically weak
due to low UV photon fluxes.
Title: VLA observations of Cyg OB2 No. 5: detection of a weak radio
companion and new observations and models for the main component.
Authors: Miralles, M. Paz; Rodríguez, L. F.; Tapia, M.; Roth, M.;
Persi, P.; Ferrari-Toniolo, M.; Curiel, S.
Bibcode: 1994RMxAA..29..218M
Altcode: 1994RMxAA..29..218P
No abstract at ADS
Title: Effect of the relative flow velocity on the structure and
stability of the magnetopause current layer
Authors: Kuznetsova, M. M.; Roth, M.; Wang, Z.; Ashour-Abdalla, M.
Bibcode: 1994JGR....99.4095K
Altcode:
The Vlasov kinetic approach is used to study the stability of the
magnetopause current layer (MCL) when a sheared flow velocity and
a sheared magnetic field both exist simultaneously within it. A
modified Harris-Sestero equilibrium where the magnetic field and
bulk velocity are changing direction on the same spatial scale
is suggested to illustrate the generation of a y component of the
magnetic field in the center of the MCL. With this equilibrium it is
shown that By(0) can be of the order of Bz(∞)
when the value of the shear flow (U) tends to the ion drift velocity
(Ud). The modifications of the initial symmetrical Harris
configuration, introduced by the presence of shear flow, strongly
influence the adiabatic interaction of the plasma with low-frequency
tearing-type electromagnetic perturbations as well as the nonadiabatic
response of the particles near the center of the MCL. This results in
a reduction of the growth rate of the tearing mode.
Title: The young stellar population associated with the HII region
NGC 3576.
Authors: Persi, P.; Roth, M.; Tapia, M.; Ferrari-Toniolo, M.; Marenzi,
A. R.
Bibcode: 1994A&A...282..474P
Altcode:
J H K images and photometry of sources associated with the HII region
NGC 3576 are presented together with an 8-13 micrometers CVF spectrum
of the most conspicuous source in the region, Irs 1. A total of 135
sources were detected in K in the surveyed area of 340 x 340 square
arc seconds. From the spatial distribution and photometry we deducted
the presence of a very young massive star cluster deeply embedded
in the molecular cloud. Comparison of the apparent K luminosity
distribution of the cluster region with that of surrounding areas,
suggests that the cluster contains more than fifty members brighter
than K approxmiately = 13, the majority of which (greater than 70%)
show significant IR excess. A steep gradient in the near-infrared color
is seen from the north-east to the south-west of the cluster indicating
that the formation of stars started further out of the cloud and as
the older population expands, it has progressed to deeper parts into
the cloud where the more recent events are taking place. In the core,
the star formation efficiency is found to be 0.19. The distance to
this cluster is estimated to be 2.4 kpc.
Title: VLA observations of CYG OB2 No 5 : detection of a weak radio
companion and new observations and models for the main component.
Authors: Miralles, M. P.; sRodríguez, L. F.; Tapia, M.; Roth, M.;
Persi, P.; Ferrari-Toniolo, M.; Curiel, S.
Bibcode: 1994A&A...282..547M
Altcode:
We present Very Large Array (VLA) observations of the contact
binary star Cyg OB2 No. 5 obtained over the last four years. A
weak (approximately 0.6 mJy at 6 cm) radio companion has been
detected approximately 0.8 sec to the NE of the known main radio
component. However, most of the radio continuum and the variability
appear to be associated with the main component (that coincides in
position with the optical contact binary). The centimeter continuum
emission of the main component increased in 1989-1992 to levels
similar to those observed in 1983-1986. The radio emission seems
to alternate between a 'low' and a 'high' state with a period of
about seven years. We derived its brightness temperature from 3.6 cm
observations during a 'high' state, obtaining TB = 100 000 +/
30 000 K. This large value rules out a possible thermal origin for the
radio continuum emission. Several models are discussed to account for
the characteristics of the radio emission from the main component. The
most satisfactory consists of a synchrotron-emitting envelope produced
near the outer region of the free-free radio phototsphere (approximately
1015 cm at cm wavelengths).
Title: UVBRI imaging photometry of Eta Carinae region
Authors: Tapia, M.; Roth, M.; Vázquez, R. A.; Feinstein, A.
Bibcode: 1994BAAA...39...78T
Altcode:
CCD Images of a large area of the Eta Car Nebula are presented. The area
covers some 60 by 30 arcmin. The images presented here were taken with
a Tektronix 1024 x 1024, blue sensitive CCD on the 1m Swope Telescope
of the Las Campanas Observatory. The images are sampled to .67 arcsec
per pixel. The average seeing during the observing run was of the
order of 1.3 arcsec. Conditions were, in general, not photometric
but individual frames have been calibrated with previous photometry
reported in several papers by Feinstein and Co-workers. Our survey
has a dynamic interval of some 8 magnitudes and includes stars to a
limit of m=20 in B and V m=18 in U, R and I. Preliminary photometric
calibrations indicate that we are observing the main sequence down to
a mass limit approximately 0.5 M⊙. When combined with JHK photometry
(see Roth et al., this meeting) we expect to determine in greater
detail the characteristics of the interstellar reddening, based on a
much bigger sample of stars and colors than currently available. These
data information will also enable us to construct more accurately the
Initial Mass-Function of this young region.
Title: JHK imaging photometry of Tr 14, Tr 15 and Tr 16
Authors: Roth, M.; Tapia, M.; Vázquez, R. A.; Feinstein, A.; Prado, P.
Bibcode: 1994BAAA...39...79R
Altcode:
We have observed the areas associated with the young open clusters Tr
14, Tr 15 and Tr 16 of the Eta Carinae Region in the near-infrared
(J, H and K'), using a NICMOS 3 array detector (256 x 256 pixels)
and the Swope lm telescope of Las Campanas Observatory. The images
are sampled to 0.45 arcsec per pixel under an average seeing of
1.5 arcsec. Calibration of these images was performed using the
magnitudes obtained for individual stars with existing single-detector
photometry. The limiting magnitudes are, approximately, 15 in J and H,
and 14.5 in the K' filter, thus greatly extending the available data
base. These data will be used with our UBVRI CCD photometry (Tapia et
al., this meeting) to determine in greater detail the interstellar and
intra-cluster extinction laws and to derive individual reddening. This
will allow us to obtain accurate distances, bolometric magnitudes,
photometric spectral types, HR diagrams and the Initial Mass Function
of each cluster. A number of very red sources have been detected and
their nature will be discussed.
Title: Near infrared images of galactic water masers
Authors: Testi, L.; Felli, M.; Persia, P.; Roth, M.
Bibcode: 1994LNP...431R.312T
Altcode:
No abstract at ADS
Title: Velocity shift in random media
Authors: Roth, M.; Müller, G.; Snieder, R.
Bibcode: 1993GeoJI.115..552R
Altcode:
No abstract at ADS
Title: The Magellan Project: a 6.5-M Telescope at Las Campanas
Authors: Roth, M.
Bibcode: 1993RMxAA..26...79R
Altcode:
The details of the 6.5 meter telescope of the Magellan Project of the
Carnegie Institution of Washington at the Las Campanas Observatory
are described.
Title: Episodic symmetric jets in the planetary nebula FG 1.
Authors: Lopez, J. A.; Roth, M.; Tapia, M.
Bibcode: 1993RMxAA..26S.110L
Altcode:
No abstract at ADS
Title: H2V = 1-0(S1) images of southern planetary nebulae.
Authors: Lopez, J. A.; Roth, M.; Tapia, M.
Bibcode: 1993RMxAA..26R.110L
Altcode:
No abstract at ADS
Title: Theoretical structure of a magnetospheric plasma boundary:
Application to the formation of discrete auroral arcs
Authors: Roth, M.; Evans, D. S.; Lemaire, J.
Bibcode: 1993JGR....9811411R
Altcode:
In the framework of a kinetic theory for tangential discontinuities
we modeled the electrical structure of the sheath that separates
magnetospheric particle populations of different densities and
temperatures. The model can equally be applied to the plasma sheet
boundary layer in the tail or to the boundary of some plasma sheet
cloud immersed in the central plasma sheet. With plasma parameters
typical of the Earth's outer magnetosphere and plasma sheet, we
obtain results bearing many features pertinent to magnetospheric
processes, specifically the origin of discrete auroral arcs. Creation
of a space-charge separation electrostatic potential in a direction
normal to the magnetic field results from the contact of the two plasma
populations. When the large-scale solar wind potential difference is
further imposed across the transition layer, the potential gradients
are locally much enhanced, to give rise to large electric fields
(several hundreds millivolts per meter) appearing over small distances
perpendicular to the magnetic field-just the situation needed for the
creation of an auroral arc. The transition itself is characterized
by two scale lengths of the plasma and fields variables: the average
electron Larmor radius curly rhoe (or some multiple of curly
rhoe) for thin embedded electron-dominated layers which
generate the sharpest potential gradients, and the ion gyroradius
ρp (or some multiple of ρp) for the broader
ion-dominated layers located at the outer edges of the transition. The
larger-scale sizes are appropriate to auroral arcs dimensions. The
generated electric potential differences, consistent with the energy
acquired by the precipitated electrons associated with discrete aurora,
are identified with the source of the electromotive force (EMF) required
for the auroral current circuit. Wave particle interactions are likely
to scatter the electrons into the atmospheric loss cone, establishing
the current system threading both the EMF and the ionosphere by means
of field-aligned currents. The half lifetime of the transition is at
least of the order of 1000 s. This is also the time interval during
which dissipative processes will not alter significantly the available
potential gradients of the initially unloaded EMF.
Title: Extended Structures in the Planetary Nebulae He2-111 and
He2-119
Authors: Lopez, J. A.; Tapia, M.; Roth, M.
Bibcode: 1993IAUS..155..208L
Altcode:
No abstract at ADS
Title: A Symmetric Jet-Like Structure in the Planetary Nebula FG-1
Authors: Lopez, J. A.; Tapia, M.; Roth, M.
Bibcode: 1993IAUS..155..203L
Altcode:
No abstract at ADS
Title: Single Scattering Theory Versus Numerical Modelling In 2-D
Random Media.
Authors: Roth, M.; Korn, M.
Bibcode: 1993GeoJI.112..124R
Altcode:
No abstract at ADS
Title: Seismic-wave traveltimes in random media
Authors: Müller, G.; Roth, M.; Korn, M.
Bibcode: 1992GeoJI.110...29M
Altcode:
No abstract at ADS
Title: Initial Results from the Las Campanas Program to Monitor QSO
Optical Brightness Variations
Authors: Sirola, C. J.; Turnshek, D. A.; Monier, E.; Sheaffer, S.;
Weymann, R. J.; Morris, S.; Duhalde, O.; Krzeminski, W.; Kunkel, W.;
Roth, M.
Bibcode: 1992AAS...180.0308S
Altcode: 1992BAAS...24..731S
We present preliminary results from a brightness monitoring program
of > 150 QSOs. Short exposures were obtained using a TI CCD on the
Las Campanas 40-inch Swope telescope. Observations of the QSOs have
been taken several times per year over the course of the last few
years. Brightness variations have been determined relative to stars
contained in the ~ 5 arcmin square CCD field. One purpose of the program
is to investigate the characteristics of the brightness variations among
various types of QSOs: (1) radio-quiet QSOs with broad absorption lines
(BALs), (2) radio-quiet QSOs without BALs and (3) radio-loud QSOs. We
find no large differences in the variability properties between these
three QSO types over a time scale of a few years. The investigation
is continuing in order to determine if more subtle differences between
the types exist or if differences are apparent on longer time scales.
Title: On impulsive penetration of solar wind plasmoids into the
geomagnetic field
Authors: Roth, M.
Bibcode: 1992P&SS...40..193R
Altcode:
The idea that solar wind plasma-field irregularities, i.e. plasmoids
with an excess momentum density penetrate deeper into the
geomagnetic field was introduced in 1976 by Lemaire and Roth at an
EGS meeting. It was based on the observation that the solar wind is
most of the time patchy over distances smaller than the diameter of
the magnetosphere. In this early paper about "impulsive penetration",
the authors did not attend to give a detailed physical description
of the underlying mechanism. When Lemaire was more informed about
some relevant laboratory plasma experiments carried out by Bostick,
Baker and Hammel or Demidenko et al., he published in 1985 [Lemaire,
J. (1985) Plasma Phys.33, 425] a physical description of the mechanism,
based on a theory first proposed by Schmidt in 1960 [Schmidt, G. (1960)
Phys. Fluids3,961]. Transient and impulsive interaction processes
between the solar wind and the magnetosphere have now become an
important and highly debated topic. In particular, Heikkila's argument
claiming that the effects of induced electric fields are the primary
cause for impulsive penetration has been shown by Owen and Cowley to be
erroneous. Although the conclusions reached by Owen and Cowley [Owen
C.J. and Cowley S. W. H. (1991) J.geophys. Res.96, 5565] are correct,
at least within the framework contrived by Heikkila (i.e. that of
ideal MHD) [Heikkila W. J. (1982) Geophys. Res. Lett.9,159], they do
not demonstrate that real plasmoids can not penetrate impulsively onto
closed geomagnetic field lines. Indeed, non-ideal MHD processes, like
collective polarization effects, formation of electrostatic potential
barriers, adiabatic and non-adiabatic brakings or collective diamagnetic
effects, have to be taken into account in the "real world". Account
of the theory of "impulsive penetration" both for weakly and strongly
diamagnetic plasmoids is given, emphasizing in which respect the entry
mechanism differs from ideal entry mechanisms like those proposed
by Schindkr in 1979 [Schindler, G. (1979) J. geophys. Res.84, 7257]
and by Heikkila in 1982.
Title: FORS: A Multi-Purpose Instrument for the ESO VLT
Authors: Appenzeller, I.; Duensing, K. H.; Fricke, K.; Gong, S.; Hess,
H. -J.; Kiesewetter, S.; Kudritzki, R. -P.; Möhler, S.; Muschielok,
B.; Nicklas, H.; Östreicher, R.; Roth, M.; Rupprecht, G.; Seifert,
W.; Stahl, O.
Bibcode: 1992ESOC...42..577A
Altcode: 1992ptit.conf..577A
No abstract at ADS
Title: High Resolution Infrared Images of the Young Cluster GM-24
Authors: Tapia, M.; Roth, M.; Lopez, J. A.
Bibcode: 1992eoim.conf..263T
Altcode:
No abstract at ADS
Title: Corrigendum
Authors: Lemaire, J.; Roth, M.
Bibcode: 1991SSRv...58..377L
Altcode:
No abstract at ADS
Title: Erratum - Infrared and Optical CCD Images of the Young Cluster
Associated with GM:24
Authors: Tapia, M.; Roth, M.; Lopez, J. A.; Rubio, M.; Persi, P.;
Ferrari-Toniolo, M.
Bibcode: 1991A&A...250..292T
Altcode:
No abstract at ADS
Title: Non-steady-state solar wind-magnetosphere interaction
Authors: Lemaire, J.; Roth, M.
Bibcode: 1991SSRv...57...59L
Altcode:
Most of the theories proposed to explain the interaction between the
solar wind and the geomagnetic field are stationary descriptions based
on ideal MHD. In this review an alternative, nonstationary description
is discussed. According to this description, most of the plasma-field
irregularities, i.e., plasmoids, detected in the solar wind can
penetrate inside the geomagnetic field beyond what is considered to
be the mean position of the magnetopause. It is the patchy solar wind
plasma impinging on the geomagnetic field which imposes rapidly changing
and non-uniform boundary conditions over the whole outer magnetospheric
surface. This contrasts with the general belief that the observed field
variations or ‘events’ arise sporadically near the magnetopause
as the result of some plasma instability. A brief historical review is
given to illustrate the evolution of the theoretical models proposed to
explain the interaction of the solar wind with the magnetosphere. The
emergence of the idea of ‘impulsive penetration’ of solar wind
plasma irregularities into the magnetosphere is emphasized especially. A
kinetic model of the unperturbed magnetopause is described. This model
corresponds to a closed magnetosphere whose surface is a tangential
discontinuity. This transition layer can sustain plasma jettings
and can be traversed by impulsive penetrating plasmoids. This is
against the general belief which considers tangential discontinuities
as the worse case with respect to impulsive penetration and plasma
jettings. The mean features of the theory of impulsive penetration
are presented. Gusty penetration of solar wind plasmoids depends on
their excess momentum density and on the orientation of the IMF. The
motion of plasmoids across non-uniform magnetic field configurations
(tangential discontinuities) is discussed theoretically. When the
dielectric constant of the streaming plasma is large enough for
collective polarization effects to become important, an electric
field develops which permits cross-B motions of all charged particles
as a whole plasma entity. It is re-emphasized that the value of the
integrated Pedersen conductivity is a determining factor in cross-B
plasma motion. On the other hand, interconnection of interplanetary
magnetic field lines and geomagnetic field lines results from collective
diamagnetic effects produced by magnetized plasmoids injected into
the magnetosphere. Several consequences of this penetration mechanism
are discussed. These are: the escape of energetic particles out of
the magnetosphere, the eastward deflection of penetrating plasmoids,
the magnetospheric and ionospheric convection patterns, the erosion of
plasmoids, and the mass/momentum loading effects. Some significant
experimental geophysical observations supporting the impulsive
penetration model are also discussed.
Title: High resolution images of the embedded cluster associated
with GM24.
Authors: Tapia, M.; Lopez, J. A.; Roth, M.; Persi, P.; Ferrari-Toniolo,
M.
Bibcode: 1991ASPC...14..252T
Altcode: 1990ASPC...14..252T
High resolution visual and IR images of the embedded young cluster
associated with the molecular cloud and "blister" H II region GM24
are presented. The cluster contains more than 23 stars, most of them
showing large IR excesses at λ ≥ 2.2 μm. The distance to the
complex is d = 2.0 kpc and the total luminosity is Ltot
≅ 1.5x105Lsun.
Title: Infrared images and radio continuum of the H II region
G 352.2+0.9.
Authors: Persi, P.; Ferrari-Toniolo, M.; Felli, M.; Roth, M.; Tapia, M.
Bibcode: 1991ASPC...14..298P
Altcode: 1990ASPC...14..298P
The component G 352.2+0.9 of the H II region/star forming complex NGC
6357 has been studied using near IR images and VLA radio continuum
observations at 6 cm.
Title: Development of a Relatchable Cover Mechanism for a Cryogenic
Ir-Sensor
Authors: Birner, R.; Lange, G.; Roth, M.; Voit, A.
Bibcode: 1991NASCP3113..125B
Altcode:
No abstract at ADS
Title: Stars at the faint end of the H-R diagram: WDs and dMs.
Authors: Ruiz, M. T.; Anguita, C.; Maza, J.; Roth, M.
Bibcode: 1991ASPC...20R.615R
Altcode:
No abstract at ADS
Title: IR images of N159 in the LMC.
Authors: Rubio, M.; Roth, M.; Tapia, M.
Bibcode: 1990RMxAA..21..249R
Altcode:
The authors obtained near infrared images in J, H, and K filters of the
H II region N159 in the LMC with the IR Imager on the 1.5 m telescope
of CTIO. Some 50 sources are detected in an area of roughly 10 arc
min squared. The region seems to be a site of active star formation
associated to a large molecular complex and possibly coincides with
one of the CO clouds which forms the molecular complex.
Title: Detection of nonlinear features in plasma and field
measurements by PROGNOZ-8.
Authors: Sokolov, A. Yu.; Khabibrakhmanov, I. Kh.; Kuznetsova, M. M.;
Lemaire, J.; Roth, M.; Lesceux, J. M.; Verheest, F.
Bibcode: 1990ESASP.311...81S
Altcode: 1990plap.rept...81S
In the present paper an example of high amplitude electric field
oscillations is considered, detected by PROGNOZ-8 near the magnetopause
at very low frequencies ranging down to fractions of Hz.
Title: Radio continuum, IR and CCD images of selected regions in
NGC 6357.
Authors: Felli, M.; Persi, P.; Roth, M.; Tapia, M.; Ferrari-Toniolo,
M.; Cervelli, A.
Bibcode: 1990A&A...232..477F
Altcode:
The H II region and star-formation complex NGC 6357 is characterized
on the basis of (1) a 25-micron IRAS map; (2) 6-cm VLA observations;
(3) optical images obtained with the 0.9-m telescope at CTIO; (4)
NIR photometry obtained with the 2.2-m telescope at ESO; and (5) CCD
images obtained in the J, H, K, L-prime, H-alpha, and I bands with the
1.5-m telescope at CTIO. The data are presented in extensive tables,
graphs, and images and discussed in detail. A clearly delineated
ionization front bounded by a dark obscuring lane is seen in the
optical/IR/radio-bright component G 353.2 + 0.9, and the early-type
stars in the cluster Pis 24 are shown to lie outside the ionization
front, so that they cannot be the source of ionization for the region
as previously assumed. Component G 353.1 + 0.6 is found to be a nearly
classical Stromgren sphere of very-low-density gas with a central
early-type star as its ionization source.
Title: Erratum - Near Infrared Images of Young Objects in the HH:1
and HH:3 Regions
Authors: Roth, M.; Tapia, M.; Rubio, M.; Rodgriquez, L. F.
Bibcode: 1990A&A...229..279R
Altcode:
No abstract at ADS
Title: Detection of Synchrotron Emission from a Unique Herbig-Haro
Object in Orion
Authors: Yusef-Zadeh, F.; Cornwell, T.; Reipurth, B.; Roth, M.
Bibcode: 1990IAUS..140..329Y
Altcode:
No abstract at ADS
Title: The "COClA", a catalogue of open cluster ages. Experiences
in data handling, and presentation of the catalogue.
Authors: Roth-Höppner, M. L.
Bibcode: 1990pess.conf..201R
Altcode:
The COClA is a compilation of published age and turn-off mass
determinations of galactic open clusters. Besides the age values,
however, it contains also information and references on all the
assumptions and quantities on which the respective age determination
is based. The present version of the catalogue contains 1260 entries
referring to 250 galactic clusters. A special chapter of the catalogue
gives a short description (in tabular form) of the most widely used
age calibration curves.
Title: Compte rendu de l'assemblée générale du 17 mars 1990:
Rapport du trésorier
Authors: Roth, M.
Bibcode: 1990C&T...106..109R
Altcode:
No abstract at ADS
Title: 13 mars 1989: une magnétosphère bien perturbée!
Authors: Roth, M.
Bibcode: 1990C&T...106...97R
Altcode:
No abstract at ADS
Title: Three-micron spectroscopy of highly reddened field stars.
Authors: Tapia, M.; Persi, P.; Roth, M.; Ferrari-Toniolo, M.
Bibcode: 1989IAUS..135P..29T
Altcode:
No abstract at ADS
Title: Three-micron spectroscopy of three highly reddened field stars.
Authors: Tapia, M.; Persi, P.; Roth, M.; Ferrari-Toniolo, M.
Bibcode: 1989A&A...225..488T
Altcode:
The 2.0-2.5 and 3.0-4.1 micron spectra of three luminous field late-type
highly reddened stars located in different regions of the galactic plane
and more than 20 deg away from the direction of the Galactic Center are
presented. The observations consist of CVF spectra with resolution of
around 70 and IRSPEC spectra with resolution of around 500. The possible
detection of the 3.4-micron absorption feature outside the Galactic
Center environment is reported. This feature has been attributed to
absorption arising in a vibrational transition resulting from the C-H
stretching in organic compounds. The observations indicate that the
agent producing the 3.4-micron feature, presumably organic molecules,
is an important component of the diffuse interstellar medium and is
not characteristic only of the Galactic Center. Bandheads of SiO are
also detected at 4.01 and 4.05 in the high resolution spectrum of the
late-type supergiant Lynga 8 Irs3.
Title: Near-infrared and optical images of the star forming region
GM-24.
Authors: Tapia, M.; Roth, M.; Rodriguez, L. F.
Bibcode: 1989RMxAA..18..177T
Altcode:
No abstract at ADS
Title: Near-Infrared Images in the Herbig-Haro 1-2 and 3 Regions
Authors: Roth, M.; Tapia, M.; Rubio, M.; Rodriguez, L. F.
Bibcode: 1989RMxAA..18Q.182R
Altcode:
No abstract at ADS
Title: Near-infrared images in the Herbig-Haro 1-2 and 3 regions.
Authors: Roth, M.; Tapia, M.; Rubio, M.; Rodríguez, L. F.
Bibcode: 1989RMxAA..18S.182R
Altcode:
No abstract at ADS
Title: Large Proper Motions in the Remarkable Triple Radio Source
in Serpens
Authors: Rodriguez, L. F.; Curiel, S.; Moran, J. M.; Mirabel, I. F.;
Roth, M.; Garay, G.
Bibcode: 1989BAAS...21..792R
Altcode:
No abstract at ADS
Title: Une aurore dans notre ciel le 13 mars 1989
Authors: Roth, M.
Bibcode: 1989C&T...105...31R
Altcode:
No abstract at ADS
Title: The Metal Line Spectra of Central Stars of Planetary Nebulae
Authors: Roth, M.; Herrero, A.; Mendez, R. H.; Kudritzki, R. P.;
Groth, K. Butler H. G.
Bibcode: 1989IAUS..131..317R
Altcode:
No abstract at ADS
Title: NGC 2899: an evolved bipolar planetary nebula.
Authors: López, J. A.; Falcón, L. H.; Ruiz, M. T.; Roth, M.
Bibcode: 1989IAUS..131..179L
Altcode:
No abstract at ADS
Title: Multifrequency observations of the cometary nebula P18
(NGC 2316).
Authors: López, J. A.; Roth, M.; Friedman, S. D.; Rodríguez, L. F.
Bibcode: 1988RMxAA..16...99L
Altcode:
Multifrequency observations have been obtained for the cometary nebula
P18 (NGC 2316). The set of data consists of CCD frames in the I and
R bands; J,H,K and Larcmin near-infrared photometry and maps in the H
and K bands, and radio continuum observations at λ 6-cm. These have
been combined with previously published photometry at 10 and 22 μm,
IRAS and Kuiper data. The results indicate that P18 is a compact H
II region located at a distance of ≡1 kpc and is being excited by
an embedded single early B-type star. Two condensations located near
the apex of the nebula, apparent in the optical-red and near-infrared
maps and previously misidentified as "stars", are related to light from
the H II region shining through the disrupted circumstellar dust shell.
Title: The interstellar extinction in the open clusters TR 14, TR 15,
TR 16/Cr 232 and CR 228 in NGC 3372 New near-infrared photometry.
Authors: Tapia, M.; Roth, M.; Marraco, H.; Ruiz, M. T.
Bibcode: 1988MNRAS.232..661T
Altcode:
Near-infrared JHKL photometry of more than 200 stars, members of the
open clusters Tr 14, Tr 15, Tr 16, Cr 228 and Cr 232 in the Carina
Nebula are presented. From comparing these results with the available
visual photometry and spectroscopy, it is found that, except in Tr 15,
the intracluster reddening is characterized by a 'normal' extinction
law at lambda of greater than 0.5 microns but is highly anomalous and
variable in the U-bands and B-bands. This behavior may be explained
by the presence of intracluster interstellar grains 'processed' by
shock waves presumably associated with the explosive history of Eta
Carinae. All clusters are found to be at the same distance from the
sun at d = 2.4 + or - 0.2 kpc. The total amount of reddening, though,
differs significantly from cluster to cluster.
Title: The blister H II region associated with GM24.
Authors: Roth, M.; Tapia, M.; Gómez, Y.; Rodríguez, L. F.
Bibcode: 1988RMxAA..16....3R
Altcode:
The authors present VLA observations of the ultracompact H II region
GM 24 in the H 76α line and 2-cm continuum with an angular resolution
of ≡1arcsec. The radio coninuum shows a blister morphology, with the
southern edge sharply bounded. The northern parts of the radio source
extend over ≡15arcsec and connect with the optical nebulosity. There
is also evidence for a velocity gradient across the face of the H II
region, with the northern part blueshifted by 6 - 8 km s-1
with respect to the southern part. The authors conclude that GM 24
is a blister H II region that has bursted out of its parent molecular
cloud and is undergoing the champagne phase.
Title: Stellar Winds from of Stars from Infrared and Radio
Observations.
Authors: Persi, P.; Rodriguez, L. F.; Tapia, M.; Ferrari-Toniolo,
M.; Roth, M.
Bibcode: 1988ASSL..142..227P
Altcode: 1988mosg.proc..227P
Infrared and radio observations of the Of stars HD 108,
HD 14947, HD 16691, HD 47129 are reported. They confirm the
presence of thermal stellar wind emission with mass loss rate 1 -
2×10-5M_sun;y-1. The radio variability on time
scale of months of the Of star Cyg OB2 No.5 is shown. This variability
is not correlated with the 10 micron excess.
Title: A new device for performing high-speed polarimetric
measurements.
Authors: Metz, K.; Kunze, D.; Roth, M.; Hofstadt, D.
Bibcode: 1987Msngr..49...24M
Altcode:
The explosion of the supernova SN 1987A in the LMC on February 23,
1987, was such an exceptional event for the present generation of
astronomers that all possible efforts are justified that could allow
a deeper insight into the somewhat spectacular results obtained for
the supernova. It is not our purpose to review here the discussions
that were triggered by the observation of two different neutrino
showers that raised the question as to whether the precursor of
SN 1987A is now a black hole or a neutron"star. If we assume the
latter, it should be possible to carry out linear as weil as circular
polarization measurements synchronous with the perhaps fast rotating
central star, as soon as the pulsar becomes visible. With respect to
the distance modulus of SN 1987A, which is of the order of 18.5, it
is evident that we cannot directly observe in the visible domain the
polarization of a central object in the supernova. However, it will
perhaps be possible to measure the interaction of a strong and quickly
varying magnetic field with the shell surrounding the pulsar. To derive
a correlation between polarization and magnetic field, it must be
possible to measure the polarization synchronously with the rotation
of the neutron star. This can be implemented in a simple way also in
the relatively slow ESO polarimeter PISCO. The intended modification
has to be carried out in such a way that absolutely no interferences
with the usual functions of the instrument can occur (Stahl et al.,
1986). Therefore the proposed changes mainly have to be shifted onto
the software facilities of the instrument. Since it requires much work
to prepare the requisite programmes at a computer we have to start our
modifications immediately and therefore at a time we are by no means
certain about the usefulness of our efforts. However, once created,
the intended modification can also be used for measuring fast varying
objects like polars of DQ Her type.
Title: On the infrared emission of the exciting star of the
Herbig-Haro objects 1 and 2.
Authors: Tapia, M.; Roth, M.; Carrasco, L.; Ruiz, M. T.
Bibcode: 1987RMxAA..14..517T
Altcode:
. New observational evidence is presented which indicates that the
infrared emission at X > 3 pm seen in the position of the VLA radio
source located between the Herbig-Haro objects 1 and 2, originates in
warm circumstellar dust around the central star which is most probably
responsible for the excitation of these Herbig-Haro objects. In the
present picture, the nearby extended emission dominating at A < 3
pm and which peaks some 9 arc sec NW of the VLA source, is considered
to be a combination of tscattered stellar light and emission of shocked
ionized gas. The visual extinction, AV, in the direction of the central
star is shown to be 23 < Av < 63. The details of the present
work will be published in Monthly Notices of the Royal Astronomical
Society. Key vjo't : HERBIG-HARO OBJECTS - STARS-CIRCUMSTELLAR SHELLS
Title: The Great Carina Nebula: normal or abnormal extinction?
Authors: Roth, M.; Tapia, M.; Ruiz, M. T.
Bibcode: 1987RMxAA..14..612R
Altcode:
ABSTRACT. The interstellar extinction in the direction of the
open clusters in the Great Carina Nebula (NGC 3372) is a matter of
controversy. While some authors have argued in favor of a normal
interstellar extinction characterized by a value of the coefficient
of total to selective absorption R of approximately 3.2 (Turner and
Moffat, 1980, M.N.R.A.S., 192, 283), values of 5 and more for the
said coefficient have been published (Herbst, 1976, Ap. 3., 208,
923. In this paper we present preliminary results of extensive ,K
(some L and A() photometry of a great number of stars in the open
clusters Tr 14, 15 and 16 and Cr 232 and 228 of NGC 3372. Our infrared
Observations were cornbined with previous observations of Feinstein
and co-worker (see Feinstein, FitzGei , and Moffat 1980, A .3.,
85, 708, and references therein). The observations were performed
on the 1.5-m telescope of CTIO). An analysis of the (V-K) vs. (B-V)
diagram shows that a unique value of the parameter R cannot be deduced
as is usual in the variable extinction method. As a matter of fact,
the boundaries of this diagram correspond to values of R between 3.2
and 5. This is an indication that the region cannot be described in a
straightforward manner by establishing a single "normal or abnormal"
value of R. We then calculated the ratio E(V-K)/E(B-V) for each of the
observed stars, after eliminating foreground stars and objects with
large observational errors. From the distribution of this ratio for each
cluster, it is clear that the peak values (which is in general assumed
to be proportional to R) vary from cluster to cluster, presenting a
"normal" value for Tr 15 and a maximum deviation for Tr 14. Tr 16 and
Cr 232 have values in between. The value for Cr 228 has no significant
peak and therefore is still an open question. (Our statistic is rather
poor for this cluster). The details of the observations as well as the
calculations and a discussion on the origin of the described effect
will be published shortly.
Title: Electric Potential Distributions at the Interface Between
Plasmasheet Clouds
Authors: Evans, D. S.; Roth, M.; Lemaire, J.
Bibcode: 1987NASCP2469..287E
Altcode: 1987dla..conf..287E
At the interface between two plasma clouds with different densities,
temperatures, and/or bulk velocities, there are large charge separation
electric fields which can be modeled in the framework of a collisionless
theory for tangential discontinuities. Two different classes of layers
have been identified: the first one corresponds to (stable) ion layers
which are thicker than one ion Larmor radius; the second one corresponds
to (unstable) electron layers which are only a few electron Larmor radii
thick. The authors suggest that these thin electron layers with large
electric potential gradients (up to 400 mV/m) are the regions where
large-amplitude electrostatic waves are spontaneously generated. These
waves scatter the pitch angles of the ambient plasmasheet electron
into the atmospheric loss cone. The unstable electrons layers can
therefore be considered as the seat of strong pitch angle scattering
for the primary auroral electrons.
Title: X-Ray Sources in Regions of Star Formation. II. The
Pre--Main-Sequence G Star HDE 283572
Authors: Walter, F. M.; Brown, A.; Linsky, J. L.; Rydgren, A. E.;
Vrba, F.; Roth, M.; Carrasco, L.; Chugainov, P. F.; Shakovskaya,
N. I.; Imhoff, C. L.
Bibcode: 1987ApJ...314..297W
Altcode:
This paper reports the detection of HDE 283572, a ninth-magnitude G star
8 arcmin south of RY Tau, as a bright X-ray source. The observations
reveal this object to be a fairly massive (about 2 solar masses)
pre-main-sequence star associated with the Taurus-Auriga star formation
complex. It exhibits few of the characteristics of the classical
T Tauri stars and is a good example of a 'naked' T Tauri star. The
star is a mid-G subgiant, of about three solar radii and rotates
with a period of 1.5 d. The coronal and chromospheric surface fluxes
are similar to those of the most active late type stars (excluding T
Tauri stars). The X-ray and UV lines most likely arise in different
atmospheric structures. Radiative losses are some 1000 times the quiet
solar value and compare favorably with those of T Tauri stars.
Title: Interstellar Extinction in Trumpler 37. Infrared Results
Authors: Roth, M.
Bibcode: 1987BAAS...19..724R
Altcode:
No abstract at ADS
Title: On the infrared emission of the exciting star of the
Herbig-Haro objects 1 and 2.
Authors: Tapia, M.; Roth, M.; Carrasco, L.; Ruiz, M. T.
Bibcode: 1987MNRAS.224..587T
Altcode:
Further evidence is presented indicating that the infrared emission at
λ > 3 μm, spatially coincident with the VLA source located midway
between the Herbig-Haro objects 1 and 2, comes from warm circumstellar
dust around the star most probably responsible for the excitation of
these Herbig-Haro objects. The nearby extended emission dominating at
shorter wavelengths comes from scattered stellar light, the shocked
ionized nebulosity, or both. The visual extinction in the direction
of the central star is 23 ⪉ AV ⪉ 63.
Title: New infrared observations of NGC 3603.
Authors: Roth, M.; Tapia, M.; Ruiz, M. T.; Persi, P.; Ferrari-Toniolo,
M.
Bibcode: 1987IAUS..115..182R
Altcode:
No abstract at ADS
Title: NGC2346 - Visible and Infrared Observations of Several
Mass-Loss Episodes
Authors: Costero, R.; Tapia, M.; Mendez, R.; Echevarria, J.; Roth,
M.; Quintero, A.; Barral, J.
Bibcode: 1987pppn.work..183C
Altcode:
New observations of the eclipses of the central star of NGC 2346 are
presented; these, together with other data available in the literature
allow the authors to elaborate on a detailed model for the obscuring
dust cloud.
Title: Near Infrared Sources in the Complex HII Region NGC6357
Authors: Persi, P.; Ferrari-Toniolo, M.; Roth, M.; Tapia, M.
Bibcode: 1987IAUS..115..187P
Altcode:
No abstract at ADS
Title: The Star Formation Region Associated with the Cometary
Nebula GM:24
Authors: Tapia, M.; Roth, M.; Rodriguez, L. F.; Canto, J.; Persi,
P.; Ferrari-Toniolo, M.; Lopez, J. A.
Bibcode: 1987IAUS..115..188T
Altcode:
No abstract at ADS
Title: Evidence of a circumstellar dust cloudlet orbiting around
the centralstar of NGC 2346.
Authors: Costero, R.; Tapia, M.; Echevarría, J.; Quintero, A.;
Barral, J. F.; Roth, M.
Bibcode: 1987IAUS..122..503C
Altcode:
Details of the present work will be published in Rev. Mexicana
Astron. Astrofis.
Title: Observations and models of the eclipse of the central star
of NGC 2346.
Authors: Costero, R.; Tapia, M.; Méndez, R. H.; Echevarría, J.;
Roth, M.; Quintero, A.; Barral, J. F.
Bibcode: 1986RMxAA..13..149C
Altcode:
The photometric behaviour of AGK3 -0°965, the central star of the
bipolar planetary nebula NGC 2346, has been monitored photometrically
for several months at the Observatorio Astronómico Nacional at
Tonantzintla and San Pedro Mártir. A model is proposed in which
the eclipses were caused by the passage of an ellipsoidal cool dust
cloudlet.
Title: A set of photometric near-infrared standard stars observed
at San Pedro Mártir.
Authors: Tapia, M.; Neri, L.; Roth, M.
Bibcode: 1986RMxAA..13..115T
Altcode:
A set of 24 JHKL'M bright standard stars in use at the Observatorio
Astronómico Nacional in San Pedro Mártir, México, is presented. A
comparison is made with similar published lists from other observatories
resulting in a set of transformation equations to and from the authors'
photometric system.
Title: Infrarerd observations and star formation in NGC 6357.
Authors: Persi, P.; Ferrari-Toniolo, M.; Roth, M.; Tapia, M.
Bibcode: 1986A&A...170...97P
Altcode:
The authors have searched for near-infrared emission from selected
areas in the H II region NGC 6357. Six fields, centred on previously
reported far-infrared peaks, on a 6 cm radio continuum peak and on
a water maser, were investigated. The detected sources were analyzed
by means of colour-colour diagrams in order to discriminate between
possible young objects and field stars and their characteristics are
discussed. It is found that the near-infrared sources associated with
NGC 6357 are less massive than the visible stars which are responsible
for the excitation of the visible H II region and that they are deeply
embedded in a molecular cloud. The possible interaction of the winds
from the visible O-type stars and the molecular material is discussed.
Title: First results with PISCO.
Authors: Stahl, O.; Buzzoni, B.; Kraus, G.; Schwarz, H.; Metz, K.;
Roth, M.
Bibcode: 1986Msngr..46...23S
Altcode: 1986Mgr....46...23S
PISCO is the acronym for the new ESO polarimeter and stands for
Polarimeter with Instrumental and Sky COmpensation. The design
of the instrument has been developed by K. Metz and the main
principles have been published in two articles in Astronomy and
Astrophysics (Metz, 1984, 1986). The instrument has been built at
the Universitätssternwarte München with the technical and financial
support of ESO and is now offered to visiting astronomers at the 2.2
m telescope at La Silla. This article briefly describes the instrument
and first results obtained during a test run in September 1986.
Title: Open Clusters in NGC 3372. Normal or Abnormal Reddening?
Authors: Tapia, M.; Roth, M.; Ruiz, M. T.
Bibcode: 1986BAAS...18.1037T
Altcode:
No abstract at ADS
Title: Study of the planetary nebula NGC 2818. I. Photometry of the
central star.
Authors: Kohoutek, L.; Roth-Hoeppner, M. L.; Laustsen, S.
Bibcode: 1986A&A...162..232K
Altcode:
The results of analyses of 17 photometric photographic plates of
the central star of the planetary nebula NGC 2818 are reported. The
plates were exposed in 1977-78 with the 3.6 m telescope at ESO-La
Silla. The V luminosity was 18.5 mag, the B-V luminosity 0.1 mag,
and the U-B luminosity was -1.22 mag. The object was determined to
be at a medium point in the evolution of a planetary nucleus. Whether
or not the nebula is in fact collocated in the open cluster NGC 2818
could not be confirmed.
Title: Radio and infrared observations of the faint nebula GM 24.
Authors: Rodriguez, L. F.; Roth, M.; Canto, J.; Tapia, M.; Persi,
P.; Ferrari-Toniolo, M.
Bibcode: 1986RMxAA..12..285R
Altcode:
The faint nebulosity CM24=PP85 listed by Parsamian and Petrosian
(1979) was observed at infrared (1-10 pm) and radio (6 cm and CO line)
wavelengths in the vicinity of the CO "hot spot" reported by Torrelles
et al. (1983). The radio continuum (6 cm) emission from a spherically
symmetrical HIl region was detected with the Very Large Array. Its
position coincides with the brightest part of the visible nebulosity
and a 1-4 pm emission peak. Our infrared maps made at the Observatorio
Astronomico Nacional de San Pedro Martir, show two additional (1-10 pm)
peaks located at distances - 30 arc sec from the compact HII region,
all surrounded by extended near infrared (1-4 pm) emission. A detailed
CO (J=1 0) map of the whole molecular cloud was also obtained with
the University of Texas Millimeter - Wave Telescope. Our results are
interpreted in terms of the recent formation of three massive stars,
one of which, having developed an HII region, is at a slightly later
phase of its evolution. The extended near infrared emission may arise
in a reflection nebula similar to NCC 7538-Irs 9 (Werner et al.,1979);
Tokunaga et al.,1981). The details of the present work will be published
at a later date.
Title: Schönberg-Chandrasekhar-Methode der Altersbestimmung Offener
Sternhaufen
Authors: Roth-Höppner, M. L.
Bibcode: 1986MitAG..67..369R
Altcode:
No abstract at ADS
Title: Remarks on the C.O.C.L.A. (Catalogue of Open Cluster Ages)
Authors: Roth-Höppner, M. L.; Höppner, W.; Winter, L.
Bibcode: 1986MitAG..67..367R
Altcode:
The C.O.C.L.A. is intended to be a complete listing of all age and
turn-off-mass determinations of galactic open clusters published
yet. The preliminary version of the C.O.C.L.A. has now 1111 entries
comprised of 250 galactic open clusters.
Title: A Computer Simulation Study of the Microscopic Structure of
a Typical Current Sheet in the Solar Wind
Authors: Roth, M.
Bibcode: 1986ASSL..123..167R
Altcode: 1986shtd.symp..167R
A numerical model for the internal structure of a typical current
sheet in the solar wind is presented which has application to the
Ulysses mission. The results indicate that the theoretical thickness
for current sheets in the solar wind is expected to be of the order
of 20 R(H+) or less. It is suggested that with the time resolution
of solar-wind plasma instruments (larger than the 1-5 s required for
vehicle to traverse a thin current sheet), the particle fluxes in
successive energy channels and solid angles be compared directly with
the values determined from theoretical velocity distributions.
Title: Multifrequency observations of the region associated with
the cometary nebula GM 24.
Authors: Tapia, M.; Roth, M.; Rodriguez, L. F.; Canto, J.; Persi,
P.; Ferrari-Toniolo, M.; Lopez, J. A.
Bibcode: 1985RMxAA..11...83T
Altcode:
The faint nebulosity GM24 = PP8S was observed at infrared (1-20 m)
and radio (6cm and CO line) wavelengths in the vicinity of a CO "hot
spot" reported previously. Radio continuum (6cm) emission from an H II
region was detected with the Very Large Array. Its position coincides
with a 1-4 m emission peak. GM24 appears to be the visible part of an
obscured H II region that is beginning to emerge from the molecular
cloud. Our infrared maps made at the Observatorio Astron6mico Nacional
at San Pedro Martir, show two additional (1-20 m) peaks located at
distances \ 30 arcsec from the compact H II region, all surrounded
by extended near-infrared (14 m) emission. A detailed CO (J = 1 0)
map of the whole molecular cloud was obtained with the University of
Texas MillimeterWave Telescope. High resolution spectroscopy of the Hα
line was also obtained with the Anglo-Australian Telescope. Our results
are interpreted in terms of recent formation of three massive stars;
one of which, having developed an H II region, is at a slightly later
phase of its evolution. The extended near-infrared emission may arise
in a reflection nebula similar to NGC 7538-Irs 9.
Title: IRAS and near-infrared observations of the Seyfert galaxies
MCG 8-11-11, MKN 79 and MKN 279.
Authors: Spinoglio, L.; Persi, P.; Ferrari-Toniolo, M.; Giovannelli,
F.; Bassani, L.; Di Cocco, G.; Clement, R. M.; Coe, M. J.; Dean,
A. J.; Sembay, S.; Roth, M.; Tapia, M.; MacDougall, J. R.; Elsmore, B.
Bibcode: 1985A&A...153...55S
Altcode:
IRAS-pointed observations and near-infrared photometry of the Seyfert
galaxies MCG 8-11-11, Mkn 79 and Mkn 279 are presented. Superimposed
on a power law behaviour with α = -1.2, MCG 8-11-11 shows an excess
at 25 μm which can be accounted for by black body emission at ≡200K
from a dust emitting region of 73 pc or more. Mkn 79 has a single power
law spectrum from 1 to 100 μm with α = -1.0. The spectrum of Mkn 279
from 12 to 100 μm can be fitted with a power law spectral index α =
-1.44, breaking to a flatter spectrum at around 10 μm. Alternatively,
the near-infrared data of this object can be interpreted in terms of a
strong galactic component emerging over the underlying power law. The
infrared observations are discussed and compared to measurements taken
from the same objects at other wavelengths.
Title: Radio and Infrared Observations of Cyg OB2 No.5
Authors: Rodriguez, L. F.; Canto, J.; Sarmiento, A.; Roth, M.; Tapia,
M.; Persi, P.; Ferrari-Toniolo, M.
Bibcode: 1985ASSL..116..127R
Altcode: 1985rst..conf..127R
VLA measurements of the 6-cm flux of Cyg OB2 No. 5 reveal it has
increased by a factor of 4 between 1980 and 1984. From July 1983 to
September 1984 the 6-cm flux has slowly increased from 5.8 to 7.3
mJy. During September 1984 the 6- and 2-cm fluxes were measured on
seven occasions. During this month, no variability was detected at the
10-percent level and the spectral index was 0.1 + or - 0.1. The 6.6-day
variability found at 2.2 microns originates from the eclipsing of the
contact binary system. There is no evidence of IR variability from the
emission originating in the ionized wind. It is as yet unclear if the
radio emission has a thermal or a nonthermal nature. A model in terms
of the ejection of a dense shell (superposed on a steady stellar wind)
is discussed.
Title: Herbig-Haro objects 1 and 2 : another infrared candidate for
their energy source.
Authors: Rodriguez, L. F.; Roth, M.; Tapia, M.
Bibcode: 1985MNRAS.214P...9R
Altcode:
A possible source for the excitation energy of Herbig-Haro objects
1 and 2 has been detected at wavelengths of 1 - 4 μm. Its position
coincides with a recent detection of a 6-cm radio continuum source and
the centre of an NH3 torus orientated perpendicularly to
the line joining H-H 1 and 2. Its infrared (1 - 200 μm) luminosity is
approximately 10 L_sun;, consistent with a reddened (AV ≅
12) T Tauri-type star. From upper limits in visual and near-infrared
plates and from infrared photometry, a reddening law which resembles
that of the Orion Belt and Sword regions has been calculated.
Title: Near-infrared sources in the molecular cloud G35.2-0.74.
Authors: Tapia, M.; Roth, M.; Persi, P.; Ferrari-Toniolo, M.
Bibcode: 1985MNRAS.213..833T
Altcode:
Near-infrared (1-4 microns) observations of the molecular cloud
G35.2-0.74 are presented. The observations were carried out using the
InSb infrared spectrometer-photometer on the 2.1-m telescope of the
Observatorio Astronomico Nacional in Mexico. The instrumentation was
described in detail in a previous study. The observations indicate the
presence of four infrared sources in the vicinity of two previously
reported centers of star formation in G35.2-0.74. The northern part of
the cloud contains three point sources which are interpreted as highly
obscured stars. The star Irs 1 coincided with H2O and OH maser emission
and appears to be a very young early-type star reddened by Av of about
54. It is suggested that Irs 1 is the source of pumping energy to the
masers, the ionizing energy to the H II regions, and the outflow that
leads to the observed bipolarity. The southern part of G35.2-0.74
shows a diffuse source at 2.2 microns with a flux distribution in
the short-wavelength region compatible with free-free emission. The
evolutionary aspects of the region are discussed in terms of the
available observations.
Title: An infrared study of the giant HII region NGC 3603.
Authors: Persi, P.; Tapia, M.; Roth, M.; Ferrari-Toniolo, M.
Bibcode: 1985A&A...144..275P
Altcode:
New infrared observations of several sources in the complex giant
H II region NGC 3603 are presented. Three sources, Irs1, Irs2, and
Irs9, embedded in the optically visible nebula, have been analyzed in
detail by means of CVF spectra between 2 and 4 microns and a 2.2-micron
map. The presence of the hydrogen Br-alpha and Br-gamma emission lines
in the spectrum of Irs1 with an intensity ratio of 0.65 suggests a
stellar wind being associated with this object. The near-infrared
energy distribution of Irs9 can be fitted by a black body at 900 K;
its spectrum is featureless in the 2 micron region while the 3.3
micron emission feature can be traced in the 3-4 micron window. HD
97950, responsible for the ionization of the giant H II-region, is
shown to have an excess emission longward of about 2 microns, which,
if interpreted as originating in an ionized stellar wind, implies a
mass-loss rate of 0.000025 solar masses/yr, typical for a Wolf-Rayet
star. Finally, the source Irs16, located NE of the bright nebula,
was classified from the strong CO and H2O absorption bands as late M;
it shows a long term variability in the K-band of about 6 mag.
Title: Time-variable, excess radio emission from CYG OB2 No5.
Authors: Persi, P.; Ferrari-Toniolo, M.; Tapia, M.; Roth, M.;
Rodriguez, L. F.
Bibcode: 1985A&A...142..263P
Altcode:
VLA measurements of the 6 cm flux of Cyg OB2 No. 5 reveal that it has
increased by a factor of 3 between 1980 and 1983. The spectral index
of this excess radio emission is 0.2±0.1. The radio variability of
this and other O-type stars recently reported appears to have time
scales of months. The evidence of a 6.6 day periodicity found at 2.2 μm
indicates that the IR variability observed in the contact binary system
Cyg OB2 No. 5 originates from the eclipsing stars instead of from the
expanding envelope. This result places important constraints on models
where the mass loss rate of the star suffers changes. It is yet unclear
if the radio emission has a thermal or a nonthermal nature. A model in
terms of the ejection of a dense shell by the O-type stars is discussed.
Title: Infrared observations of the planetary nebula NGC 2346.
Authors: Roth, M.; Echevarria, J.; Tapia, M.; Carrasco, L.; Costero,
R.; Rodriguez, L. F.
Bibcode: 1984PASP...96S.794R
Altcode:
No abstract at ADS
Title: Near-Infrared Sources in the Molecular Cloud G35.2-0.74
Authors: Roth, M.; Tapia, M.; Persi, P.; Ferrari-Toniolo, M.
Bibcode: 1984BAAS...16..919R
Altcode: 1984BAAS...16..918R
No abstract at ADS
Title: Infrared light curves of the central object of NGC 2346 :
the shape of the obscuring cloud.
Authors: Roth, M.; Echevarria, J.; Tapia, M.; Carrasco, L.; Costero,
R.; Rodriguez, L. F.
Bibcode: 1984A&A...137L...9R
Altcode:
Infrared light curves of the central object of NGC 2346 show that
the observed flux originates from the central A-type star and a
warm circumstellar dust cloud. Two eclipses are seen in the J and H
bands instead of the single eclipse previously reported from visual
measurements. No light modulation is present at longer wavelengths. A
simple model in terms of the passage of an elongated cloud can account
for most of the existing observations.
Title: Near-infrared and visual photometry of H and KHI Persei.
Authors: Tapia, M.; Roth, M.; Costero, R.; Navarro, S.
Bibcode: 1984RMxAA...9...65T
Altcode:
Broad-band near-infrared photometry in the JHK (and sometimes L' and M)
bands of 82 stars in h and x Persei is presented. The stars observed
cover the upper main sequence of the central parts of the clusters
as well as the giants and supergiants of the extended region. New
UBV photoelectric photometry of 24 stars for which only photographic
photometry was previously available is also reported. The infrared
results are consistent with a unique value of the extinction in the
direction of both clusters of AV= 1.85 ± 0.12. Comparisons between
the infrared and visual data suggest that the observed dispersion
towards large values of E(B- is not due to variable reddening as
previously stated in the literature but that it may be intrinsic to
the atmosphere of some B-type stars. Infrared excesses were found
in the brightest B and A-type supergiants. These are explained by
bremsstrahlung associated with their hot stellar winds. Most of the
Be stars in x Persei also present significant infrared excesses due
to circumstellar dust emission or bremsstrahlung or both.
Title: An Infrared Photometric and Spectrometric System in San-Pedro
Authors: Roth, M.; Iriarte, A.; Tapia, M.; Resendiz, G.
Bibcode: 1984RMxAA...9...25R
Altcode:
A new infrared photorneter-spectrometer has recently been put into
operation on the 2.1-m telescope of the Observatorio Astronomico
Nacional in San Pedro Martir, Baja California. The system, which
was partially designed and built in our Institute, allows wide-band
photometry in the 1 to 20 μm wavelength range and low resolution
(λ/Δλ ∼ 100) spectrometry in the 2.0 to 3.9 μm region using
InSb photovoltaic and Ge bolometer detectors. The various components
of the system are described and tests carried out on the telescope
are presented.
Title: La structure interne de la magnétopause.
Authors: Roth, M.
Bibcode: 1984MmARB..44....1R
Altcode:
The kinetic model developed in this paper aims to give a description
of the internal structure of the magnetopause. It takes, among other
factors, the interplanetary magnetic field and the thermal motion
of the particles into account. These factors have been neglected in
previous theories. This model describes the structure of a tangential
discontinuity in a multi-component collisionless plasma. Furthermore,
from the consideration of the two-stream instabilities a minimum
magnetopause thickness can be deduced. The tangential discontinuities
observed at the magnetopause are linked to regions where magnetosheath
and magnetospheric plasmas are interpenetrated.
Title: Infrared and Visual Observations of H-Persei and Chi-Persei
Authors: Tapia, M.; Roth, M.; Costero, R.; Navarro, S.
Bibcode: 1984IAUS..105..353T
Altcode:
Near-infrared observations of 82 stars in h and χ Persei (NGC 869 and
884) were obtained. (J-H) vs (H-K) and (H-K) vs (K-L) diagrams are
presented. From the infrared data alone, the authors find a unique
value for the extinction in the direction of both clusters and for
stars of all luminosity classes. From the infrared characteristics two
clearly distinguishable groups of B supergiants are found. Most of the
Be stars in χ Persei present significant infrared excesses. Schild's
(1967) suggestion is supported that h Persei is younger, by a factor
of two in age, than χ Persei.
Title: Une première dans la magnétosphère... Expériences actives
dans un plasma cosmique: le projet AMPTE
Authors: Roth, M.
Bibcode: 1984C&T...100..150R
Altcode:
No abstract at ADS
Title: Interdisciplinary study of directional discontinuities in
the solar wind with ISPM.
Authors: Lemaire, J.; Roth, M.; Scherer, M.; Schulz, M.
Bibcode: 1983ESASP1050..263L
Altcode:
The solar-wind plasma contains large-scale as well as small-scale
plasma irregularities or inhomogeneities. Theoretical models of these
discontinuities will be developed as part of the ISPM investigation. The
magnetic and particle observations obtained by ISPM will be used
to check these models, and consequently to identify fundamental
plasma-physical processes.
Title: Boundary layers in space plasmas: a kinetic model of tangential
discontinuities.
Authors: Roth, M.
Bibcode: 1983pig..conf..139R
Altcode:
No abstract at ADS
Title: A Catalogue of Open Cluster Ages
Authors: Roth, M. L.
Bibcode: 1983MitAG..60..429R
Altcode:
No abstract at ADS
Title: Density scaling of the angular momentum versus mass universal
relationship
Authors: Carrasco, L.; Roth, M.; Serrano, A.
Bibcode: 1982A&A...106...89C
Altcode:
The relationship between angular momentum density j and mass M is
investigated for a number of astronomical objects, and an updated
version of the log j versus log M diagram is presented. It is shown
that the specific angular momentum density follows an M to the k power
law, where k is greater than or equal to 2/3 but less than or equal
to 3/4. It is also found that this relationship is scaled by a weak
power of the density, and that this density dependence increases the
slope of the log j-log M relation when it is derived for a sample of
objects with different mean density values. The power law is explained
in terms of the mechanical equilibrium between gravitational and
rotational energy (Ozernoy, 1967). The relationship may also be used
to predict a relationship between radius and mass for flat galaxies,
with M at the 0.33-0.5 power. This conclusion is found to be in close
agreement with observations.
Title: Zum Alter offener Sternhaufen
Authors: Roth, M. L.
Bibcode: 1982MitAG..55..201R
Altcode:
No abstract at ADS
Title: La magnétosphère terrestre.
Authors: Roth, M.
Bibcode: 1982Ciel...44....8R
Altcode:
No abstract at ADS
Title: Differences between solar wind plasmoids and ideal
magnetohydrodynamic filaments
Authors: Lemaire, J.; Roth, M.
Bibcode: 1981P&SS...29..843L
Altcode:
Plasma irregularities present in the solar wind are plasmoids,
i.e. plasma-magnetic field entities. These actual plasmoids differ
from ideal magnetohydrodynamic (MHD) filaments. Indeed, (1) their
"skin" is not infinitely thin but has a physical thickness which is
determined by the gyromotion of the thermal ions and electrons, (2)
they are of finite extent and their magnetic flux is interconnected
with the interplanetary magnetic flux, (3) when they penetrate into
the magnetosphere their magnetic field lines become rooted in the
ionosphere (i.e. in a medium with finite transverse conductivity), (4)
the external Lorentz force acting on their boundary surface depends on
the orientation of their magnetic moment with respect to the external
magnetic field, (5) when their mechanical equilibrium is disturbed,
hydromagnetic oscillations can be generated. It is also suggested that
the front side of all solar wind plasmoids which have penetrated into
the magnetosphere is the inner edge of the magnetospheric boundary
layer while the magnetopause is considered to be the surface where the
magnetospheric plasma ceases to have a trapped pitch angle distribution.
Title: A Drive Unit for the Instrument Pointing System
Authors: Birner, R.; Roth, M.
Bibcode: 1981NASCP2181..263B
Altcode:
No abstract at ADS
Title: Differences between solar wind plasmoids and ideal
magnetohydrodynamic filaments
Authors: Lemaire, J.; Roth, M.
Bibcode: 1981STIN...8218110L
Altcode:
The time dependent impulsive penetration model of solar wind
plasma-magnetosphere interaction is elaborated on in order to emphasize
its differences from ideal MHD models. The plasma-magnetic field
entities differ from ideal MHD filaments. Their skin is not infinitely
thin, but has a physical thickness determined by the gyromotion of the
thermal ions and electrons. They are finite and their magnetic flux
is interconnected with the interplanetary magnetic flux. When they
penetrate into the magnetosphere their magnetic field lines become
rooted in the ionosphere, i.e., in a medium with finite transverse
conductivity. The external Lorentz force acting on their boundary
surface depends on the orientation of their magnetic moment with respect
to the external magnetic field. When their mechanical equilibrium is
perturbed, hydromagnetic oscillations can be generated. The front side
of all solar wind plasmoids which penetrate into the magnetosphere is
considered to be the inner edge of the magnetospheric boundary layer,
while the magnetopause is the surface where the magnetospheric plasma
ceases to have a trapped pitch angle distribution.
Title: La magnétosphère terrestre.
Authors: Roth, M.
Bibcode: 1981Ciel...43..269R
Altcode:
No abstract at ADS
Title: Altersbestimmung offener Sternhaufen mit Hilfe von
Sternmodellen an der Schönberg-Chandrasekhar-Grenze
Authors: Roth, M. L.
Bibcode: 1981MitAG..52..126R
Altcode:
No abstract at ADS
Title: On the initial distribution and evolution of angular momentum
for main sequence stars .
Authors: Carrasco, L.; Franco, J.; Roth, M.
Bibcode: 1980A&A....86..217C
Altcode:
From published photometric periods for BY Dra type stars, the angular
momentum per unit mass (J/M) for a number of these objects has been
computed. The compound values of J/M show that the late type main
sequence flare stars have high angular velocities and that their
distribution of J/M for spectral types later than K0V, as a function of
mass, exceeds by several orders of magnitude any possible extrapolation
of the same distribution for intermediate masses. A simple model,
developed to explain these results is described.
Title: VLBI System for Weekly Measurement of UTI and Polar Motion:
Preliminary Results
Authors: Roth, M.; Yunck, T.
Bibcode: 1980TDAPR..58...15R
Altcode: 1980tdar.nasa...15R
The DSN implementation of a system for measuring UT1 and polar motion
using very long baseline interferometry (VLBI) is currently being
tested. The VLBI experiments are being conducted on a weekly basis
on each of two intercontinental baselines. During a 17 day period in
September 1979, data were obtained for seven consecutive experiments
using an early version of that system. Those experiments were used to
refine the estimation procedure to be used in the operational system and
to provide a preliminary assessment of the performance of the system.
Title: The Galactic Distribution of Angular Momentum Density and
Star Formation
Authors: Carrasco, L.; Serrano, A.; Roth, M.
Bibcode: 1980BAAS...12R.445C
Altcode:
No abstract at ADS
Title: Density Scaling of the Specific Angular Momentum (J/M) in
the Universe
Authors: Carrasco, L.; Roth, M.; Serrano, A.
Bibcode: 1980BAAS...12Q.445C
Altcode:
No abstract at ADS
Title: A photometer for infrared astronomy.
Authors: Roth, M.; Carrasco, L.; Franco, J.; Resendiz, G.
Bibcode: 1980RMxF...27...39R
Altcode:
No abstract at ADS
Title: More on avoided level crossing of non-radial stellar
oscillations
Authors: Roth, M. L.; Weigert, A.
Bibcode: 1979A&A....80...48R
Altcode:
Adiabatic linear non-radial oscillations were calculated for stars with
masses from 5 to 16 solar masses which are evolving through central
hydrogen burning. The eigenvalues, vorticities, and (quasi-adiabatic)
damping times of the resulting normal modes are discussed with regard
to the avoided level crossing.
Title: Photometric study of trapezium-type systems.
Authors: Echevarria, J.; Roth, M.; Warman, J.
Bibcode: 1979RMxAA...4..287E
Altcode:
UBVRI photometry for 68 multiple systems of Ambartsumian's list is
presented and analyzed. We conclude that the incidence of optical
systems is much higher than expected; we also find that several
selection effects are noticeable in the catalog. No obvious sign of
youth seems to be present throughout the sample.
Title: Visual and infrared observations of trapezium-like objects.
Authors: Roth, M.; Echevarria, J.; Franco, J.; Warman, J.
Bibcode: 1979RMxAA...4..209R
Altcode:
UBVRIKLMQ observations are presented on seven trapezium like objects,
previously reported to have abnormally high infrared fluxes. We
conclude that in four cases the source responsible for the infrared
flux does not correspond to a member of the trapezium system under
consideration; in the three remaining cases, the infrared fluxes are
due to the presence of bright and very cool stars. These results and
their consequences are discussed.
Title: Control of impulsive penetration of solar wind irregularities
into the magnetosphere by the interplanetary magnetic field direction
Authors: Lemaire, J.; Rycroft, M. J.; Roth, M.
Bibcode: 1979P&SS...27...47L
Altcode:
Impulsive penetration of a solar wind filament into the magnetosphere
is possible when the plasma element has an excess momentum density with
respect to the background medium. This first condition is satisfied when
the density is larger inside than outside the plasma inhomogeneity. In
this paper we discuss the second condition which must be satisfied
for such a plasma element to be captured by the magnetosphere: the
magnetization vector ( M) carried by this plasma must have a positive
component along the direction of B0, the magnetic field where
the element penetrates through the magnetopause. On the contrary, when M
· B0 < 0 , the filament is stopped at the surface of the
magnetopause. Thus the outcome of the interaction of the filament with
the magnetosphere depends upon the orientation of the Interplanetary
Magnetic Field. For instance, penetration and capture in the frontside
magnetosphere implies that Bsw, the Interplanetary Magnetic
Field, has a southward, or a small northward, component. Penetration
and capture in the northern lobe of the magnetotail is favoured for an
IMF pointing away from the Sun; in the southern lobe Bsw
must be directed towards the Sun for capture. Finally, for capture
in the vicinity of the polar cusps the magnetospheric field (
B0) assumes a wider range of orientations. Therefore, near
the neutral points, it is easier to find a place where the condition M
· B0 > 0 is satisfied than elsewhere. As a consequence,
the penetration and capture of solar wind irregularities in the cleft
regions is possible for almost any orientation of the interplanetary
magnetic field direction. All observations made to date support these
theoretical conclusions.
Title: Photometric Study of Trapezium-Type Systems
Authors: Echevarria, J.; Roth, M.; Warman, J.
Bibcode: 1978BAAS...10..650E
Altcode:
No abstract at ADS
Title: Evolution and Angular Momentum in the Main Sequence
Authors: Carrasco, L.; Franco, J.; Roth, M.
Bibcode: 1978BAAS...10..695C
Altcode:
No abstract at ADS
Title: Penetration of solar wind plasma elements into the
magnetopause.
Authors: Lemaire, J.; Roth, M.
Bibcode: 1978JATP...40..331L
Altcode: 1978STIN...7925967L
The theory that the solar wind is made up of intertwined filamentary
plasma elements with dimensions smaller than the diameter of the
magnetosphere is considered, and it is suggested that these elements
can dent the magnetopause, and that they can become partially engulfed
in the magnetosphere. A number of magnetospheric observations are cited
to support this penetration mechanism which does not rely on magnetic
field merging.
Title: Structure of tangential discontinuities at the magnetopause:
the nose of the magnetopause.
Authors: Roth, M.
Bibcode: 1978JATP...40..323R
Altcode:
A description of the nose region of the magnetopause is attempted on
the basis of a theoretical model of the magnetopause as a tangential
discontinuity. The tangential discontinuity in the magnetic field is
described in terms of a kinetic theory based on Maxwell's equations
and Vlasov's equations for each particle species. With no electric
potential difference between the two sides of the sheath in the nose
region, computations show the existence of an electron-dominated layer
where the electric current is carried mainly by electrons. This layer
is unstable, so that the electrons become more isotropic and the layer
broadens. True ion (or electron) layers are constructed by imposing a
suitable electric potential difference between the two faces of the
sheath in order to keep the electron (or ion) velocity distribution
Maxwellian everywhere.
Title: Evolution of stars with two shell sources: the second loop
in the H-R diagram.
Authors: Hoeppner, W.; Kaehler, H.; Roth, M. L.; Weigert, A.
Bibcode: 1978A&A....63..391H
Altcode:
A model evolving through the second loop during He-shell source burning
can be divided into two basic regions which are treated separately:
a contracting C-O core and an envelope with two shell sources which
is close to an equilibrium structure. Sequences of such envelopes for
a 9-solar-mass star are presented, and it is shown how they interact
with a contracting core to form a loop in the H-R diagram. Conditions
for the occurrence of this evolution are given.
Title: Der zweite "loop" im HRD
Authors: Höppner, W.; Kähler, H.; Roth, M. L.; Weigert, A.
Bibcode: 1978MitAG..43R.236H
Altcode:
No abstract at ADS
Title: Control of pulse penetration of solar wind irregularities
into the magnetosphere by the interplanetary magnetic field direction
Authors: Lemaire, J.; Rycroft, M. J.; Roth, M.
Bibcode: 1978STIN...7925968L
Altcode:
A condition which must be satisfied for a plasma element to be captured
by the magnetosphere is that the magnetization vector M carried
by this plasma must have a positive component along the direction
of B, the magnetic field where the element penetrates through the
magnetopause. Otherwise, when MB 0 the filament is stopped at the
surface of the magnetopause. Thus the outcome of the interaction of
the filament with the magnetosphere depends upon the orientation of
the interplanetary magnetic field. Therefore, it is easier to find a
place near the neutral points where the condition MB 0 is satisfied
than elsewhere. As a consequence, the penetration and capture of
solar wind irregularities in the cleft regions is possible for almost
any orientation of the interplanetary magnetic field direction. All
observations made to date support these theoretical conclusions.
Title: Penetration of solar wind plasma elements into the
magnetosphere
Authors: Lemaire, J.; Roth, M.
Bibcode: 1976STIN...7727055L
Altcode:
Considering that the solar wind is unsteady and non-uniform, it is
suggested that field aligned plasma elements dent the magnetopause
surface. This indentation makes the magnetopause boundary convex, and
therefore locally unstable with respect to flute instabilities. The
intruding element is braked and stopped within 1 or 2 earth radii from
the magnetopause. Its excess convection kinetic energy is dissipated in
the lower polar cusp ionosphere in time lapses of 50 to 500 seconds
depending on the value of integrated Pedersen conductivity. Once
the plasma element has been engulfed, keeping its identity, the warm
plasma content is dissipated by precipitation and by drifting. The
magnetosheath particles with large pitch angles are mirrored, and
feed the plasma mantle flow. Several consequences of this penetration
mechanism are pointed out: ionospheric heating beneath the polar cusp;
Birkeland currents on the eastward and westward edges of the plasma
element; diamagnetic field fluctuations within 1-2 RE from
the magnetopause (multiple magnetopause crossings); oscillation of
the magnetopause surface after a new element has penetrated; exit of
energetic particles out of the magnetosphere, and entry of energetic
solar wind particles into the magnetosphere along the magnetic field
lines of the intruding element; magnetic flux is substracted from
the dayside magnetosphere and added to the geomagnetic tail when the
magnetic field of the element has a southward component.
Title: The plasmapause as a plasma sheath: a minimum thickness.
Authors: Roth, M.
Bibcode: 1976JATP...38.1065R
Altcode:
The plasmapause is considered as a stationary boundary layer (a sheath)
separating two types of plasmas characterized by different temperatures
and densities: on one side, the hot trapped particles imbedded in the
cold exospheric plasma of ionospheric origin; on the other side, the
plasmatrough including the hot ring-current particles. The structure
of this layer is described by a kinetic model using the Vlasov-Maxwell
equations for the charged particles and fields. In the absence of any
collisional effects or wave-particle interactions, a minimum value for
the thickness of the plasmapause is deduced which is of the order of
5 times the Larmor radius of the cold ions.
Title: The plasmapause as a plasma sheath: A minimum thickness
Authors: Roth, M.
Bibcode: 1976STIN...7629109R
Altcode:
The plasmapause is considered as a stationary boundary layer (a sheath)
separating two types of plasmas characterized by different temperatures
and densities: on one side, the hot trapped particles imbedded in the
cold exospheric plasma of ionospheric origin, and on the other side the
plasmatrough including the hot ring current particles. The structure of
this layer is described by a kinetic model using the Vlasov-Maxwell's
equations for the charged particles and fields. In the absence of any
collisional effects or wave-particle interactions a minimum value for
the thickness of the plasmapause is deduced which is of the order of
5 times the Larmor radius of the cold ions.
Title: The effects of different field aligned ionization models on the
electron densities and total flux tube contents deduced from whistlers
Authors: Roth, M.
Bibcode: 1975AnG....31...69R
Altcode:
Results are compared which are obtained when different physical
and empirical models for the ionization distribution along whistler
propagation paths are used for whistler analysis. Five models are
briefly described, including the empirical r-to-the-inverse-fourth-power
model, the constant density model, the diffusion equilibrium model, the
gyrofrequency model, the collisionless model of Evitar et al. (1964)
for a nonrotating planet, and a similar one developed by Lemaire
(1973) which includes a finite rotation rate. The equatorial and
exobase densities are calculated for these models together with the
total flux-tube content, nose frequency - time delay characteristics
are computed, and the first model is used as the reference for
the comparisons. The results indicate that inferred values of the
equatorial densities are not as sensitive to the model choice as are
the electron densities at 1000 km altitude. Good agreement is found
between the reference model and the physical exospheric models of
Evitar et al. and Lemaire, providing strong support for the validity
of the kinetic theory of ion-exospheres.
Title: Theoretical discussion of the binary system AS Eridani.
Authors: Refsdal, S.; Roth, M. L.; Weigert, A.
Bibcode: 1975MSRSL...8..431R
Altcode: 1975phs..conf..431R
No abstract at ADS
Title: Diskussion des Doppelsternsystems AS Eridani
Authors: Refsdal, S.; Roth, M. L.; Weigert, A.
Bibcode: 1975MitAG..36...95R
Altcode:
No abstract at ADS
Title: On the binary system AS Eri.
Authors: Refsdal, S.; Roth, M. L.; Weigert, A.
Bibcode: 1974A&A....36..113R
Altcode:
Summary. The very accurate observations of the semidetached system AS
Eri by Popper (1973) require a corresponding refinement of the theory of
binary evolution to white dwarfs. Here we discuss mainly the influence
of chemical profiles and loss of angular momentum. The internal state
of the present subgiant component and the future and past evolution of
the system are discussed. The past evolution offers the problem that
many possibilities are left for the initial conditions, the ranges of
which are discussed. A loss of angular momentum since the onset of mass
exchange is indicated. Key words: binary systems evolution mass exchange
Title: On the Secular Stability of Models with an Isothermal Core
Authors: Gabriel, M.; Roth, M. L.
Bibcode: 1974A&A....32..309G
Altcode:
Summary. The secular stability of models with an isothermal core is
discussed. The determinant of secular stability for (7=0 is related
to quantities defined as far as possible at the surface of the core
and at the bottom of the envelope. This relation is used to discuss
the validity of 2 intuitive criteria for secular stability. Key words:
stellar structure - evolution - secular stability
Title: Beispiele für Mehrfachlösungen bei Sternmodellen
Authors: Roth, M. L.; Weigert, A.
Bibcode: 1973MitAG..32..240R
Altcode:
No abstract at ADS
Title: Die Abhängigkeit der Schönberg-Chandrasekhar-Grenze vom
Wasserstoff-Profil
Authors: Roth, M. L.
Bibcode: 1973MitAG..34...82R
Altcode:
No abstract at ADS
Title: Examples of Multiple Solutions for Equilibrium Stars with
Helium Cores
Authors: Roth, M. L.; Weigert, A.
Bibcode: 1972A&A....20...13R
Altcode:
Summary. The different types of equilibrium configurations are discussed
for stars with He-cores and hydrogen rich envelopes. As an example,
a star of given mass and chemical composition is treated for which
up to six solutions are shown to exist. - The Henyey determinant H
vanishes, i.e. infinitely neighbouring solutions exist, when He-burning
equilibrium models of 9 M0 become secularly unstable. Real stars avoid
this by appreciable g-values which keep H always finite. Key words:
stellar structure - multiple solutions
Title: Secular instabilities in supergiant stars.
Authors: Lauterborn, D.; Refsdal, S.; Roth, M. L.
Bibcode: 1972css..conf..355L
Altcode: 1971css..conf..355L
No abstract at ADS
Title: Stars with Central Helium Burning and the Occurrence of Loops
in the H-R Diagram. II. Secular Instabilities During the Loops
Authors: Lauterborn, D.; Refsdal, S.; Roth, M. L.
Bibcode: 1971A&A....13..119L
Altcode:
The central He-burning phase of stars with 7 Me and 9 Me has been
investigated. Th some cases secular instabfflties occur during the
loops, particularly when the mass of the star is high, and when the
ratio of mixing length to pressure scale-height (1/Hp) is low. Due to
this effect, the time a star (M> 6 Me) needs to cross the Cepheid
strip can in some cases increase considerably when 1/Hp is increased,
so that the expected number of Cepheids with long periods wnl increase
with increasing 1/Hp. Key words: stellar evolution - helium buring -
loops - secular instabilities - Cepheids
Title: Time scales of stars during the crossing of the cepheid strip.
Authors: Lauterborn, D.; Refsdal, S.; Roth, M. L.
Bibcode: 1971ndnf.coll...96L
Altcode:
No abstract at ADS