Author name code: okamoto ADS astronomy entries on 2022-09-14 author:"Okamoto, Takenori J." ------------------------------------------------------------------------ Title: Quiet Sun Center to Limb Variation of the Linear Polarization Observed by CLASP2 Across the Mg II h and k Lines Authors: Rachmeler, L. A.; Bueno, J. Trujillo; McKenzie, D. E.; Ishikawa, R.; Auchère, F.; Kobayashi, K.; Kano, R.; Okamoto, T. J.; Bethge, C. W.; Song, D.; Ballester, E. Alsina; Belluzzi, L.; Pino Alemán, T. del; Ramos, A. Asensio; Yoshida, M.; Shimizu, T.; Winebarger, A.; Kobelski, A. R.; Vigil, G. D.; Pontieu, B. De; Narukage, N.; Kubo, M.; Sakao, T.; Hara, H.; Suematsu, Y.; Štěpán, J.; Carlsson, M.; Leenaarts, J. Bibcode: 2022ApJ...936...67R Altcode: 2022arXiv220701788R The CLASP2 (Chromospheric LAyer Spectro-Polarimeter 2) sounding rocket mission was launched on 2019 April 11. CLASP2 measured the four Stokes parameters of the Mg II h and k spectral region around 2800 Å along a 200″ slit at three locations on the solar disk, achieving the first spatially and spectrally resolved observations of the solar polarization in this near-ultraviolet region. The focus of the work presented here is the center-to-limb variation of the linear polarization across these resonance lines, which is produced by the scattering of anisotropic radiation in the solar atmosphere. The linear polarization signals of the Mg II h and k lines are sensitive to the magnetic field from the low to the upper chromosphere through the Hanle and magneto-optical effects. We compare the observations to theoretical predictions from radiative transfer calculations in unmagnetized semiempirical models, arguing that magnetic fields and horizontal inhomogeneities are needed to explain the observed polarization signals and spatial variations. This comparison is an important step in both validating and refining our understanding of the physical origin of these polarization signatures, and also in paving the way toward future space telescopes for probing the magnetic fields of the solar upper atmosphere via ultraviolet spectropolarimetry. Title: Shock Recovery of Granite with a Decaying Shock Wave: Feather Features Formation in Quartz Authors: Tada, T.; Kurosawa, K.; Ono, H.; Hamann, C.; Okamoto, T.; Niihara, T.; Matsui, T. Bibcode: 2022LPICo2678.1733T Altcode: We carried out shock recovery of granite with decaying compressive pulses, focusing on Feather Features (FFs) formation in quartz. FFs were formed at 8-18GPa. Title: 2021 Stellar Occultation Observation of Asteroid (3200) PHAETHON for the DESTINY+ Flyby Authors: Arai, T.; Yoshida, F.; Hayamizu, T.; Akitaya, H.; Okamoto, T.; Noda, H.; Ishiguro, M.; Urakawa, S.; Horaguchi, T.; Yamamoto, M. -Y.; Hashimoto, G.; Matsuura, S.; Marshall, S.; Destiny+ Occultation Observation Team Bibcode: 2022LPICo2678.2916A Altcode: Result of stellar occultation of Phaethon in 2021 in Japan is reported. Title: Shock Effects in Pre-Heated Basalt: Search for the Criteria for Producing Mosaicism Authors: Ono, H.; Kurosawa, K.; Niihara, T.; Mikouchi, T.; Tomioka, N.; Okamoto, T.; Matsui, T. Bibcode: 2022LPICo2678.1566O Altcode: We conducted a shock recovery experiment using basalt with a pre-heating devise. The recovered sample was processed into a thin section and investigated. Title: Shock Recovery of Granite with a Decaying Shock Wave: Fragmentation, Formation of Stishovite, and Onset of Melting at Low (<20 GPa) Shock Pressure Authors: Hamann, C.; Kurosawa, K.; Kaufmann, F. E. D.; Ono, H.; Tada, T.; Niihara, T.; Okamoto, T.; Matsui, T. Bibcode: 2022LPICo2678.2020H Altcode: Fragmemtation, stishovite formation, and shear-induced melting in granite at low (<20 GPa) shock pressure are investigated in novel shock-recovery experiments. Title: Development Status of DESTINY+ Onboard Cameras for Flyby Imaging of (3200) Phaethon Authors: Ishibashi, K.; Hong, P.; Okamoto, T.; Yamada, M.; Okudaira, O.; Suzaki, Y.; Ishimaru, T.; Ozaki, N.; Hosonuma, T.; Sato, S.; Arai, T.; Yoshida, F.; Kagitani, M.; Kameda, S.; Miyabara, T.; Ohta, M.; Takashima, T. Bibcode: 2022LPICo2678.1729I Altcode: We present the development status of two cameras onboard DESTINY+ spacecraft for flyby imaging of the asteroid (3200) Phaethon. Title: Shock Recovery of Macro Blocks of Rocky Materials with Decaying Shock Waves Authors: Kurosawa, K.; Ono, H.; Niihara, T.; Mikouchi, T.; Sakaiya, T.; Kondo, T.; Tomioka, N.; Genda, H.; Tada, T.; Tada, R.; Kayama, M.; Koike, M.; Sano, Y.; Matsuzaki, T.; Murayama, M.; Satake, W.; Okamoto, T.; Matsui, T. Bibcode: 2021LPICo2609.6163K Altcode: We have developed an experimental technique for shock recovery with decaying compressive pulses. The method allows as to collect a shocked sample experienced a variety of peak pressure depending on the initial location only at a single shot. Title: Mapping of Solar Magnetic Fields from the Photosphere to the Top of the Chromosphere with CLASP2 Authors: McKenzie, D.; Ishikawa, R.; Trujillo Bueno, J.; Auchere, F.; del Pino Aleman, T.; Okamoto, T.; Kano, R.; Song, D.; Yoshida, M.; Rachmeler, L.; Kobayashi, K.; Narukage, N.; Kubo, M.; Ishikawa, S.; Hara, H.; Suematsu, Y.; Sakao, T.; Bethge, C.; De Pontieu, B.; Vigil, G.; Winebarger, A.; Alsina Ballester, E.; Belluzzi, L.; Stepan, J.; Asensio Ramos, A.; Carlsson, M.; Leenaarts, J. Bibcode: 2021AAS...23810603M Altcode: Coronal heating, chromospheric heating, and the heating & acceleration of the solar wind, are well-known problems in solar physics. Additionally, knowledge of the magnetic energy that powers solar flares and coronal mass ejections, important drivers of space weather, is handicapped by imperfect determination of the magnetic field in the sun's atmosphere. Extrapolation of photospheric magnetic measurements into the corona is fraught with difficulties and uncertainties, partly due to the vastly different plasma beta between the photosphere and the corona. Better results in understanding the coronal magnetic field should be derived from measurements of the magnetic field in the chromosphere. To that end, we are pursuing quantitative determination of the magnetic field in the chromosphere, where plasma beta transitions from greater than unity to less than unity, via ultraviolet spectropolarimetry. The CLASP2 mission, flown on a sounding rocket in April 2019, succeeded in measuring all four Stokes polarization parameters in UV spectral lines formed by singly ionized Magnesium and neutral Manganese. Because these ions produce spectral lines under different conditions, CLASP2 thus was able to quantify the magnetic field properties at multiple heights in the chromosphere simultaneously, as shown in the recent paper by Ishikawa et al. In this presentation we will report the findings of CLASP2, demonstrating the variation of magnetic fields along a track on the solar surface and as a function of height in the chromosphere; and we will illustrate what is next for the CLASP missions and the demonstration of UV spectropolarimetry in the solar chromosphere. Title: Development of Two Types of NIR Spectral Camera for Lunar Missions SLIM and LUPEX Authors: Saiki, K.; Ohtake, M.; Nakauchi, Y.; Shiraishi, H.; Ishihara, Y.; Sato, H.; Honda, C.; Maeda, T.; Yamanaka, C.; Nagaoka, H.; Sakai, S.; Sawai, S.; Fukuda, S.; Kushiki, K.; Ebizuka, N.; Sasaki, M.; Okamoto, T.; Kayama, M.; Demura, H.; Kitazato, K.; Ogawa, Y.; Mikouchi, T.; Hirano, T. Bibcode: 2021LPI....52.2303S Altcode: The concept and development status of two spectroscopic cameras for the lunar missions Smart Lander for Investigating Moon (SLIM) project and Lunar Polar Exploration (LUPEX) project are introduced. Title: Current Status of DESTINY+ and Updated Understanding of Its Target Asteroid (3200) Phaethon Authors: Arai, T.; Yoshida, F.; Kobayashi, M.; Ishibashi, K.; Kimura, H.; Hirai, T.; Hong, P.; Wada, K.; Senshu, H.; Yamada, M.; Srama, R.; Krüger, H.; Ishiguro, M.; Yabuta, H.; Nakamura, T.; Kobayashi, S.; Watanabe, J.; Ito, T.; Ootsubo, T.; Ohtsuka, K.; Tachibana, S.; Mikouchi, T.; Morota, T.; Komatsu, M.; Nakamura-Messenger, K.; Sasaki, S.; Hiroi, T.; Abe, S.; Urakawa, S.; Hirata, N.; Demura, H.; Komatsu, G.; Noguchi, T.; Sekiguchi, T.; Kinoshita, D.; Kaneda, H.; Kameda, S.; Matsuura, S.; Ito, M.; Yamaguchi, A.; Yanagisawa, T.; Kurosaki, H.; Okamoto, T.; Nakato, A.; Yano, H.; Yoshikawa, M.; Dunham, D. W.; Buie, M. W.; Taylor, P. A.; Marshall, S.; Ozaki, N.; Yamamoto, T.; Imamura, H.; Toyota, H.; Nishiyama, K.; Takashima, T. Bibcode: 2021LPI....52.1896A Altcode: We present the current status Of DESTINY+ mission, review the results of extensive astronomical observation of the target asteroid (3200) Phaethon. Title: Development of Cameras Onboard DESTINY+ Spacecraft for Flyby Observation of (3200) Phaethon Authors: Ishibashi, K.; Hong, P.; Okamoto, T.; Ishimaru, T.; Okazaki, N.; Hosonuma, T.; Sato, S.; Arai, T.; Yoshida, F.; Okudaira, O.; Kagitani, M.; Miyabara, T.; Ohta, M.; Takashima, T. Bibcode: 2021LPI....52.1405I Altcode: We present the development status of two cameras onboard DESTINY+ spacecraft for observing the asteroid (3200) Phaethon and the preparation for the flyby imaging with them. Title: A puzzling non-detection of [O III] and [C II] from a z ≈ 7.7 galaxy observed with ALMA Authors: Binggeli, C.; Inoue, A. K.; Hashimoto, T.; Toribio, M. C.; Zackrisson, E.; Ramstedt, S.; Mawatari, K.; Harikane, Y.; Matsuo, H.; Okamoto, T.; Ota, K.; Shimizu, I.; Tamura, Y.; Taniguchi, Y.; Umehata, H. Bibcode: 2021A&A...646A..26B Altcode: 2020arXiv201113319B Context. Characterizing the galaxy population in the early Universe holds the key to understanding the evolution of these objects and the role they played in cosmic reionization. However, there have been very few observations at the very highest redshifts to date.
Aims: In order to shed light on the properties of galaxies in the high-redshift Universe and their interstellar media, we observe the Lyman-α emitting galaxy z7_GSD_3811 at z = 7.664 with bands 6 and 8 at the Atacama Large Millimeter/submillimeter Array (ALMA).
Methods: We target the far-infrared [O III] 88 μm and [C II] 158 μm emission lines and dust continuum in the star-forming galaxy z7_GSD_3811 with ALMA. We combine these measurements with earlier observations in the rest-frame ultraviolet (UV) in order to characterize the object and compare the results to those of earlier studies that observed [O III] and [C II] emission in high-redshift galaxies.
Results: The [O III] 88 μm and [C II] 158 μm emission lines are undetected at the position of z7_GSD_3811, with 3σ upper limits of 1.6 × 108 L⊙ and 4.0 × 107 L⊙, respectively. We do not detect any dust continuum in band 6 nor band 8. The measured rms in the band 8 and band 6 continua are 26 and 9.9 μJy beam-1, respectively. Similar to several other high-redshift galaxies, z7_GSD_3811 exhibits low [C II] emission for its star formation rate compared to local galaxies. Furthermore, our upper limit on the [O III] line luminosity is lower than the previously observed [O III] lines in high-redshift galaxies with similar UV luminosities. Our ALMA band 6 and 8 dust continuum observations imply that z7_GSD_3811 likely has a low dust content, and our non-detections of the [O III] and [C II] lines could indicate that z7_GSD_3811 has a low metallicity (Z ≲ 0.1 Z⊙). Title: Mapping solar magnetic fields from the photosphere to the base of the corona Authors: Ishikawa, Ryohko; Bueno, Javier Trujillo; del Pino Alemán, Tanausú; Okamoto, Takenori J.; McKenzie, David E.; Auchère, Frédéric; Kano, Ryouhei; Song, Donguk; Yoshida, Masaki; Rachmeler, Laurel A.; Kobayashi, Ken; Hara, Hirohisa; Kubo, Masahito; Narukage, Noriyuki; Sakao, Taro; Shimizu, Toshifumi; Suematsu, Yoshinori; Bethge, Christian; De Pontieu, Bart; Dalda, Alberto Sainz; Vigil, Genevieve D.; Winebarger, Amy; Ballester, Ernest Alsina; Belluzzi, Luca; Štěpán, Jiří; Ramos, Andrés Asensio; Carlsson, Mats; Leenaarts, Jorrit Bibcode: 2021SciA....7.8406I Altcode: 2021arXiv210301583I Routine ultraviolet imaging of the Sun's upper atmosphere shows the spectacular manifestation of solar activity; yet we remain blind to its main driver, the magnetic field. Here we report unprecedented spectropolarimetric observations of an active region plage and its surrounding enhanced network, showing circular polarization in ultraviolet (Mg II $h$ & $k$ and Mn I) and visible (Fe I) lines. We infer the longitudinal magnetic field from the photosphere to the very upper chromosphere. At the top of the plage chromosphere the field strengths reach more than 300 gauss, strongly correlated with the Mg II $k$ line core intensity and the electron pressure. This unique mapping shows how the magnetic field couples the different atmospheric layers and reveals the magnetic origin of the heating in the plage chromosphere. Title: Optical design of the Chromospheric LAyer Spectro-Polarimeter (CLASP2) Authors: Tsuzuki, Toshihiro; Ishikawa, Ryohko; Kano, Ryouhei; Narukage, Noriyuki; Song, Donguk; Yoshida, Masaki; Uraguchi, Fumihiro; Okamoto, Takenori J.; McKenzie, David; Kobayashi, Ken; Rachmeler, Laurel; Auchere, Frederic; Trujillo Bueno, Javier Bibcode: 2020SPIE11444E..6WT Altcode: Chromospheric LAyer Spectro-Polarimeter (CLASP2) was a sounding rocket experiment, which is a follow-up mission to the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP1) in 2015. To measure the magnetic fields in the upper solar atmosphere in a highly quantitative manner, CLASP2 changes the target wavelengths from the hydrogen Ly-α line (121.567 nm) to Mg II lines near 280 nm. We reused the main structure and most of the optical components in the CLASP1 instrument, which reduced the turnaround time and cost. We added a magnifying optical system to maintain the wavelength resolution, even at the longer wavelength of CLASP2. Here, we describe the optical design and performance of the CLASP2 instrument. Title: IRIS Mg II Observations and Non-LTE Modeling of Off-limb Spicules Authors: Tei, A.; Gunár, S.; Heinzel, P.; Okamoto, T. J.; Štěpán, J.; Jejčič, S.; Shibata, K. Bibcode: 2020AGUFMSH0010008T Altcode: We investigated the off-limb spicules observed in the Mg II h and k spectral lines by Interface Region Imaging Spectrograph (IRIS) in a solar polar coronal hole. We analyzed the large data set of obtained spectra to extract quantitative information about the line intensities, line shifts, and line widths. The observed Mg II line profiles are broad and double peaked at lower altitudes, broad but flat topped at middle altitudes, and narrow and single peaked with the largest Doppler shifts at higher altitudes. We used one-dimensional non-LTE vertical slab models (i.e., models that consider departures from local thermodynamic equilibrium) in single-slab and multi-slab configurations to interpret the observations and to investigate how a superposition of spicules along a line of sight (LOS) affects the synthetic Mg II line profiles. The employed multi-slab models are either static, i.e., without any LOS velocities, or assume randomly assigned LOS velocities of individual slabs, representing the spicule dynamics. We performed such single-slab and multi-slab modeling for a broad set of model input parameters and examined the dependence of the Mg II line profiles on these parameters. In this presentation, we demonstrate that the observed line widths of the Mg h and k line profiles are strongly affected by the presence of multiple spicules along the LOS. We also show that the profiles obtained at higher altitudes can be reproduced by single-slab models representing individual spicules. We found that the multi-slab model with a random distribution of the LOS velocities ranging from −25 to 25 km/s can well reproduce the width and the shape of the Mg II profiles observed at middle altitudes. Title: Flyby Observation of Asteroid (3200) Phaethon to Be Conducted by Cameras Onboard DESTINY+ Spacecraft Authors: Ishibashi, K.; Hong, P.; Okamoto, T.; Ishimaru, T.; Sato, S.; Yamada, M.; Okudaira, O.; Arai, T.; Yoshida, F.; Kameda, S.; Kagitani, M.; Iwata, T.; Okada, T.; Takashima, T. Bibcode: 2020LPI....51.1698I Altcode: We will report the progress of conceptual studies of the flyby observation of the asteroid (3200) Phaethon by DESTINY+ spacecraft with two onboard cameras. Title: Detections of far-infrared [O III] and dust emission in a galaxy at z = 8.312: Early metal enrichment in the heart of the reionization era Authors: Tamura, Y.; Mawatari, K.; Hashimoto, T.; Inoue, A. K.; Zackrissonm, E.; Christensen, L.; Binggeli, C.; Matsuda, Y.; Matsuo, H.; Takeuchi, T. T.; Asano, R. S.; Sunaga, K.; Shimizu, I.; Okamoto, T.; Yoshida, N.; Lee, M.; Shibuya, T.; Taniguchi, Y.; Umehata, H.; Hatsukade, B.; Kohno, K.; Ota, K. Bibcode: 2020IAUS..341..211T Altcode: We present ALMA detection of the [O III] 88 μm line and 850 μm dust continuum emission in a Y-dropout Lyman break galaxy, MACS0416_Y1. The [O III] detection confirms the object with a spectroscopic redshift to be z = 8.3118±0.0003. The 850 μm continuum intensity (0.14 mJy) implies a large dust mass on the order of 4×106M⊙. The ultraviolet-to-far infrared spectral energy distribution modeling, where the [O III] emissivity model is incorporated, suggests the presence of a young (τage ≍ 4 Myr), star-forming (SFR ≍ 60M⊙yr-1), and moderately metal-polluted (Z ≍ 0.2Z⊙) stellar component with a stellar mass of 3 × 108M⊙. An analytic dust mass evolution model with a single episode of star formation does not reproduce the metallicity and dust mass in ≍ 4 Myr, suggesting an underlying evolved stellar component as the origin of the dust mass. Title: Estimating the Temperature and Density of a Spicule from 100 GHz Data Obtained with ALMA Authors: Shimojo, Masumi; Kawate, Tomoko; Okamoto, Takenori J.; Yokoyama, Takaaki; Narukage, Noriyuki; Sakao, Taro; Iwai, Kazumasa; Fleishman, Gregory D.; Shibata, Kazunari Bibcode: 2020ApJ...888L..28S Altcode: 2019arXiv191205714S We succeeded in observing two large spicules simultaneously with the Atacama Large Millimeter/submillimeter Array (ALMA), the Interface Region Imaging Spectrograph (IRIS), and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory. One is a spicule seen in the IRIS Mg II slit-jaw images and AIA 304 Å images (Mg II/304 Å spicule). The other one is a spicule seen in the 100 GHz images obtained with ALMA (100 GHz spicule). Although the 100 GHz spicule overlapped with the Mg II/304 Å spicule in the early phase, it did not show any corresponding structures in the IRIS Mg II and AIA 304 Å images after the early phase. It suggests that the spicules are individual events and do not have a physical relationship. To obtain the physical parameters of the 100 GHz spicule, we estimate the optical depths as a function of temperature and density using two different methods. One is using the observed brightness temperature by assuming a filling factor, and the other is using an emission model for the optical depth. As a result of comparing them, the kinetic temperature of the plasma and the number density of ionized hydrogen in the 100 GHz spicule are ∼6800 K and 2.2 × 1010 cm-3. The estimated values can explain the absorbing structure in the 193 Å image, which appear as a counterpart of the 100 GHz spicule. These results suggest that the 100 GHz spicule presented in this Letter is classified to a macrospicule without a hot sheath in former terminology. Title: IRIS Mg II Observations and Non-LTE Modeling of Off-limb Spicules in a Solar Polar Coronal Hole Authors: Tei, Akiko; Gunár, Stanislav; Heinzel, Petr; Okamoto, Takenori J.; Štěpán, Jiří; Jejčič, Sonja; Shibata, Kazunari Bibcode: 2020ApJ...888...42T Altcode: 2019arXiv191112243T We investigated the off-limb spicules observed in the Mg II h and k lines by IRIS in a solar polar coronal hole. We analyzed the large data set of obtained spectra to extract quantitative information about the line intensities, shifts, and widths. The observed Mg II line profiles are broad and double peaked at lower altitudes, broad but flat topped at middle altitudes, and narrow and single peaked with the largest Doppler shifts at higher altitudes. We use one-dimensional non-LTE vertical slab models (I.e., models that consider departures from local thermodynamic equilibrium) in single-slab and multi-slab configurations to interpret the observations and to investigate how a superposition of spicules along the line of sight (LOS) affects the synthetic Mg II line profiles. The used multi-slab models either are static, I.e., without any LOS velocities, or assume randomly assigned LOS velocities of individual slabs, representing the spicule dynamics. We conducted such single-slab and multi-slab modeling for a broad set of model input parameters and showed the dependence of the Mg II line profiles on these parameters. We demonstrated that the observed line widths of the h and k line profiles are strongly affected by the presence of multiple spicules along the LOS. We later showed that the profiles obtained at higher altitudes can be reproduced by single-slab models representing individual spicules. We found that the multi-slab model with a random distribution of the LOS velocities ranging from -25 to 25 km s-1 can well reproduce the width and the shape of Mg II profiles observed at middle altitudes. Title: High-frequency Wave Propagation Along a Spicule Observed by CLASP Authors: Yoshida, Masaki; Suematsu, Yoshinori; Ishikawa, Ryohko; Okamoto, Takenori J.; Kubo, Masahito; Kano, Ryouhei; Narukage, Noriyuki; Bando, Takamasa; Winebarger, Amy R.; Kobayashi, Ken; Trujillo Bueno, Javier; Auchère, Frédéric Bibcode: 2019ApJ...887....2Y Altcode: The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) sounding rocket experiment, launched in 2015 September, observed the hydrogen Lyα line (121.6 nm) in an unprecedented high temporal cadence of 0.3 s. CLASP performed sit-and-stare observations of the quiet Sun near the limb for 5 minutes with a slit perpendicular to the limb and successfully captured an off-limb spicule evolving along the slit. The Lyα line is well suited for investigating how spicules affect the corona because it is sensitive to higher temperatures than other chromospheric lines, owing to its large optical thickness. We found high-frequency oscillations of the Doppler velocity with periods of 20-50 s and low-frequency oscillation of periods of ∼240 s on the spicule. From a wavelet analysis of the time sequence data of the Doppler velocity, in the early phase of the spicule evolution, we found that waves with a period of ∼30 s and a velocity amplitude of 2-3 km s-1 propagated upward along the spicule with a phase velocity of ∼470 km s-1. In contrast, in the later phase, possible downward and standing waves with smaller velocity amplitudes were also observed. The high-frequency waves observed in the early phase of the spicule evolution would be related with the dynamics and the formation of the spicules. Our analysis enabled us to identify the upward, downward, and standing waves along the spicule and to obtain the velocity amplitude of each wave directly from the Doppler velocity for the first time. We evaluated the energy flux by the upward-propagating waves along the spicule, and discussed the impact to the coronal heating. Title: Estimating the temperature and density of a spicule from 100 GHz data obtained with ALMA Authors: Shimojo, M.; Kawate, T.; Okamoto, T. J.; Yokoyama, T. Bibcode: 2019AGUFMSH41F3336S Altcode: We succeeded in observing two large spicules simultaneously with the Atacama Large Millimeter/submillimeter Array (ALMA), the Interface Region Imaging Spectrograph explorer (IRIS), and the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory. One is a spicule seen in the IRIS Mg II slit-jaw images and AIA 304 Å images (MgII/304Å spicule). The other one is a spicule seen in the 100 GHz images obtained with ALMA (100 GHz spicule). Although the 100 GHz spicule in the early phase overlapped with the MgII/304Å spicule, we cannot find any remarkable enhancement temporally and spatially caused by the 100 GHz spicule in the IRIS Mg II and AIA 304 Å images. Moreover, there is no overlapped region between the 100 GHz spicule and Mg II/304Å spicule in the late phase. It would suggest that the spicules are individual events and do not have a physical relationship. To obtain the physical parameters of the 100 GHz spicule from the ALMA data, we estimated two optical depths of the 100 GHz spicule from the observed brightness temperature and an emission model with assumed temperature and density. As a result of comparing them, the temperature and density of the 100 GHz spicule are 4000 - 7000 K and 2.2×1010 cm-3. The estimated values can explain the absorbing structure that is the counterpart of the 100 GHz spicule in the 193Å image. Title: Explosive Crater Experiments of Porous Gypsum Targets Authors: Nakamura, A. M.; Ogawa, K.; Murakami, Y.; Yamasaki, Y.; Nagaashi, Y.; Nomura, K.; Kadono, T.; Suetsugu, R.; Kawai, N.; Tanaka, S.; Okamoto, T. Bibcode: 2019LPICo2157.6349N Altcode: Explosive crater experiments were conducted using porous gypsum targets to investigate the similarity between the results of explosive and impact events for porous targets. Title: Novel gratings for astronomical observations Authors: Ebizuka, N.; Okamoto, T.; Takeda, M.; Hosobata, T.; Yamagata, Y.; Sasaki, M.; Kamizuka, T.; Tanaka, I.; Hattori, T.; Ozaki, S.; Aoki, W. Bibcode: 2019SPIE11180E..69E Altcode: We introduce novel gratings for next generation instruments of the TMT (Thirty Meter Telescope), the 8.2 m Subaru telescope, other ground-based and space-borne telescopes. The reflector facet transmission (RFT) grating which is a surface relief grating with sawtooth shaped grating lattice of an acute vertex angle, is developed for the WFOS of the TMT. The hybrid grism (direct vision grating) for the MOIRCSof the 8.2m Subaru Telescope is developed as a prototype of the RFT grating. The volume binary grating is developed for a high-dispersion echelle grism of the nuMOIRCS as the first light instrument of the ULTIMATE Subaru. We also developing a silicon grism for the MIMIZUKU of the 6.5m telescope of the University of Tokyo Atacama Observatory in Chile and a quasi-Bragg (QB) immersion grating. Title: The Chromospheric Layer Spectro-Polarimeter (CLASP2) Sounding Rocket Mission: First Results Authors: McKenzie, David Eugene; Ishikawa, Ryohko; Kano, Ryouhei; Rachmeler, Laurel; Trujillo Bueno, Javier; Kobayashi, Ken; Song, Donguk; Yoshida, Masaki; Auchere, Frederic; Okamoto, Takenori Bibcode: 2019AAS...23412601M Altcode: A major challenge for heliophysics is to decipher the magnetic structure of the chromosphere, because of its vital role in the transport of energy into the corona and solar wind. Routine satellite measurements of the chromospheric magnetic field will dramatically improve our understanding of the chromosphere and its connection to the rest of the solar atmosphere. Before such a satellite can be considered for flight, we must refine the measurement techniques by exploring emission lines with a range of magnetic sensitivities. In 2015, CLASP achieved the first measurement of linear polarization produced by scattering processes in a far UV resonance line (hydrogen Lyman-α), and the first exploration of the magnetic field (via the Hanle effect) and geometrical complexity in quiet regions of the chromosphere-corona transition region. These measurements are a first step towards routine quantitative characterization of the local thermal and magnetic conditions in this key layer of the solar atmosphere.

Nonetheless, Lyman-α is only one of the magnetically sensitive spectral lines in the UV spectrum. CLASP2 extends the capability of UV spectropolarimetry by acquiring ground-breaking measurements in the Mg II h and k spectral lines near 280 nm, whose cores form about 100 km below the Lyman-α core. These lines are sensitive to a larger range of field strengths than Lyman-α, through both the Hanle and Zeeman effects. CLASP2 will capture measurements of linear and circular polarization to enable the first determination of all 4 Stokes parameters in chromospheric UV radiation. Coupled with numerical modeling of the observed spectral line polarization (anisotropic radiation pumping with Hanle, Zeeman and magneto-optical effects), CLASP2 is a pathfinder for determination of the magnetic field's strength and direction, as well as of the geometry of the plasma in the upper solar chromosphere.

CLASP2 will launch from White Sands Missile Range in April 2019. In this presentation, we will summarize the characteristics of the CLASP2 flight, the performance of the UV telescope and spectropolarimeter, and our preliminary findings. Title: Multi-wavelength Multi-height Study of Super Strong Surface and Coronal Magnetic Fields in Active Region 12673 Authors: Wang, Haimin; Chen, Bin; Jing, Ju; Yu, Sijie; Liu, Chang; Yurchyshyn, Vasyl B.; Ahn, Kwangsu; Okamoto, Takenori; Toriumi, Shin; Cao, Wenda; Gary, Dale E. Bibcode: 2019AAS...23440205W Altcode: Using the joint observations of Goode Solar telescope (GST), Expanded Owens Valley Solar Array (EOVSA), Solar Dynamics Observatory (SDO) and Hinode, we study the Solar Active Region (AR) 12673 in September 2017, which is the most flare productive AR in the solar cycle 24. GST observations show the strong photospheric magnetic fields (nearly 6000 G) in polarity inversion line (PIL) and apparent photospheric twist. Consistent upward flows are also observed in Dopplergrams of Hinode, HMI and GST at the center part of that section of PIL, while the down flows are observed in two ends, indicating that the structure was rising from subsurface. Combining Non-Linear Force Free Extrapolation and EOVSA microwave imaging spectroscopy, we also look into the coronal structure of magnetic fields in this unusual AR, including the evolution before and after the X9.3 flare on September 6, 2017. Coronal fields between 1000 and 2000 gauss are found above the flaring PIL at the height range between 8 and 4Mm, outlining the structure of a fluxrope or sheared arcade. Title: Lyman-α imaging polarimetry with the CLASP2 sounding rocket mission Authors: Kano, Ryouhei; Ishikawa, Ryohko; McKenzie, David Eugene; Trujillo Bueno, Javier; Song, Donguk; Yoshida, Masaki; Okamoto, Takenori; Rachmeler, Laurel; Kobayashi, Ken; Auchere, Frederic Bibcode: 2019AAS...23430216K Altcode: Ultraviolet polarimetry offers a unique opportunity to explore the upper solar chromosphere and the transition region (TR) to the million-degree corona. These outer atmospheric regions play a key role in the transfer of mass and energy from the solar photosphere to the corona. With a sounding rocket experiment called the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), in September 2015 we succeeded in obtaining the first measurement of the linear polarization produced by scattering processes in the hydrogen Lyman-α line of the solar disk radiation. The analysis and interpretation of such spectro-polarimetric observation allowed us to obtain information on the geometrical complexity of the corrugated surface that delineates the TR, as well as on the magnetic field strength via the Hanle effect. At the same time, the CLASP slit-jaw (SJ) optics system, which is a Lyman-α filter imager characterized by a FWHM= 7 nm, allowed us to obtain broad-band Stokes-I and Q/I images over a large field of view. The obtained broad-band Q/I images are dominated by the scattering polarization signals of the Lyman-α wings, and not by the much weaker line-center signals where the Hanle effect operates. Recently, Alsina Ballester et al. (2019, ApJ, in press) showed that the scattering polarization signals of the Lyman-α wings are sensitive to chromospheric magnetic fields via the magneto-optical effects. Therefore, Lyman-α imaging polarimetry is of scientific interest also for magnetic-field investigations. On April 11, 2019, we performed another sounding rocket experiment, called the Chromospheric LAyer Spectro-Polarimeter (CLASP2). We used the same instrument after significant modifications in order to obtain spectro-polarimetric observations of a plage and a quiet region in the ionized magnesium lines around 280 nm (i.e., the Mg II h & k lines). At the same time, the CLASP2 SJ optics system allowed us to obtain broad-band Q/I and U/I images at the Lyman-α wavelength, in addition to the well-known SJ intensity images. In this presentation, we provide a first overview of the CLASP2 SJ data. Title: Shock Devolatilization/Vaporization of Evaporites in an Open System Authors: Kurosawa, K.; Moriwaki, R.; Komatsu, G.; Okamoto, T.; Yabuta, H.; Matsui, T. Bibcode: 2019LPI....50.2442K Altcode: Shock vaporization/devolatilization from evaporitic minerals, halite and gypsum, was investigated in an open system. Title: Cameras to Be Installed on the Destiny+ Spacecraft: Telescopic Camera for Phaethon (TCAP) and Multiband Camera for Phaethon (MCAP) Authors: Ishibashi, K.; Kameda, S.; Kagitani, M.; Hong, P.; Yamada, M.; Okudaira, O.; Arai, T.; Yoshida, F.; Sato, S.; Ishimaru, T.; Okamoto, T.; Iwata, T.; Okada, T.; Takashima, T. Bibcode: 2019LPI....50.1758I Altcode: We will report the progress of conceptual studies of the telescopic camera and the multiband camera for the asteroid 3200 Phaethon flyby mission DESTINY+. Title: Blue-wing enhancement of the chromospheric Mg II h and k lines in a solar flare Authors: Tei, Akiko; Sakaue, Takahito; Okamoto, Takenori J.; Kawate, Tomoko; Heinzel, Petr; UeNo, Satoru; Asai, Ayumi; Ichimoto, Kiyoshi; Shibata, Kazunari Bibcode: 2018PASJ...70..100T Altcode: 2018PASJ..tmp...61T; 2018arXiv180305237T We performed coordinated observations of AR 12205, which showed a C-class flare on 2014 November 11, with the Interface Region Imaging Spectrograph (IRIS) and the Domeless Solar Telescope (DST) at Hida Observatory. Using spectral data in the Si IV 1403 Å, C II 1335 Å, and Mg II h and k lines from IRIS and the Ca II K, Ca II 8542 Å, and Hα lines from DST, we investigated a moving flare kernel during the flare. In the Mg II h line, the leading edge of the flare kernel showed an intensity enhancement in the blue wing and a smaller intensity of the blue-side peak (h2v) than that of the red-side one (h2r). The blueshift lasted for 9-48 s with a typical speed of 10.1 ± 2.6 km s-1, which was followed by a high intensity and a large redshift with a speed of up to 51 km s-1 detected in the Mg II h line. The large redshift was a common property for all six lines, but the blueshift prior to it was found only in the Mg II lines. Cloud modeling of the Mg II h line suggests that the blue-wing enhancement with such a peak difference could have been caused by a chromospheric-temperature (cool) upflow. We discuss a scenario in which an upflow of cool plasma is lifted up by expanding hot plasma owing to the deep penetration of non-thermal electrons into the chromosphere. Furthermore, we found that the blueshift persisted without any subsequent redshift in the leading edge of the flare kernel during its decaying phase. The cause of such a long-lasting blueshift is also discussed. Title: ALMA Observations of the Solar Chromosphere on the Polar Limb Authors: Yokoyama, Takaaki; Shimojo, Masumi; Okamoto, Takenori J.; Iijima, Haruhisa Bibcode: 2018ApJ...863...96Y Altcode: 2018arXiv180701411Y We report the results of the Atacama Large Millimeter/sub-millimeter Array (ALMA) observations of the solar chromosphere on the southern polar limb. Coordinated observations with the Interface Region Imaging Spectrograph (IRIS) are also conducted. ALMA provided unprecedented high spatial resolution in the millimeter band (≈2.″0) at 100 GHz frequency with a moderate cadence (20 s). The results are as follows. (1) The ALMA 100 GHz images show saw-tooth patterns on the limb, and a comparison with Solar Dynamics Observatory/Atmospheric Imaging Assembly 171 Å images shows a good correspondence of the limbs with each other. (2) The ALMA animation shows a dynamic thorn-like structure elongating from the saw-tooth patterns on the limb, with lengths reaching at least 8″, thus suggesting jet-like activity in the ALMA microwave range. These ALMA jets are in good correspondence with the IRIS jet clusters. (3) A blob-ejection event is observed. By comparing with the IRIS Mg II slit-jaw images, the trajectory of the blob is located along the spicular patterns. Title: Wavefront error measurements and alignment of CLASP2 telescope with a dual-band pass cold mirror coated primary mirror Authors: Yoshida, Masaki; Song, Donguk; Ishikawa, Ryoko; Kano, Ryouhei; Katsukawa, Yukio; Suematsu, Yoshinori; Narukage, Noriyuki; Kubo, Masahito; Shinoda, Kazuya; Okamoto, Takenori J.; McKenzie, David E.; Rachmeler, Laurel A.; Auchère, Frédéric; Trujillo Bueno, Javier Bibcode: 2018SPIE10699E..30Y Altcode: "Chromospheric LAyer Spectro-Polarimeter (CLASP2)" is the next sounding rocket experiment of the "Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP)" that succeeded in observing for the first time the linear polarization spectra in the hydrogen Lyman-α line (121.6 nm) and is scheduled to be launched in 2019. In CLASP2, we will carry out full Stokes-vector spectropolarimetric observations in the Mg ii h and k lines near 280 nm with the spectro-polarimeter (SP), while imaging observations in the Lyman-α line will be conducted with the slitjaw optics (SJ). For the wavelength selection of CLASP2, the primary mirror of the telescope uses a new dual-band pass cold mirror coating targeting both at 121.6 nm and 280 nm. Therefore, we have to perform again the alignment of the telescope after the installation of the recoated primary mirror. Before unmounting the primary mirror from the telescope structure, we measured the wave-front error (WFE) of the telescope. The measured WFE map was consistent with what we had before the CLASP flight, clearly indicating that the telescope alignment has been maintained even after the flight. After the re-coated primary mirror was installed the WFE was measured, and coma aberration was found to be larger. Finally, the secondary mirror shim adjustments were carried out based on the WFE measurements. In CLASP2 telescope, we improved a fitting method of WFE map (applying 8th terms circular Zernike polynomial fitting instead of 37th terms circular Zernike fitting) and the improved method enables to achieve better performance than CLASP telescope. Indeed, WFE map obtained after the final shim adjustment indicated that the required specification (< 5.5 μm RMS spot radius) that is more stringent than CLASP telescope was met. Title: Optical alignment of the high-precision UV spectro-polarimeter (CLASP2) Authors: Song, Donguk; Ishikawa, Ryohko; Kano, Ryouhei; Yoshida, Masaki; Tsuzuki, Toshihiro; Uraguchi, Fumihiro; Shinoda, Kazuya; Hara, Hirohisa; Okamoto, Takenori J.; Auchère, Frédéric; McKenzie, David E.; Rachmeler, Laurel A.; Trujillo Bueno, Javier Bibcode: 2018SPIE10699E..2WS Altcode: Chromospheric LAyer Spectro-Polarimeter (CLASP2) is our next sounding rocket experiment after the success of Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP1). CLASP2 is scheduled to launch in 2019, and aims to achieve high precision measurements (< 0.1 %) of the linear and circular polarizations in the Mg ii h and k lines near the 280 nm, whose line cores originate in the upper solar chromosphere. The CLASP2 spectro-polarimeter follows very successful design concept of the CLASP1 instrument with the minimal modification. A new grating was fabricated with the same radius of curvature as the CLASP1 grating, but with a different ruling density. This allows us to essentially reuse the CLASP1 mechanical structures and layout of the optics. However, because the observing wavelength of CLASP2 is twice longer than that of CLASP1, a magnifier optical system was newly added in front of the cameras to double the focal length of CLASP2 and to maintain the same wavelength resolution as CLASP1 (0.01 nm). Meanwhile, a careful optical alignment of the spectro-polarimeter is required to reach the 0.01 nm wavelength resolution. Therefore, we established an efficient alignment procedure for the CLASP2 spectro-polarimeter based on an experience of CLASP1. Here, we explain in detail the methods for achieving the optical alignment of the CLASP2 spectro-polarimeter and discuss our results by comparing with the performance requirements. Title: DESTINY+ Mission: Flyby of Geminids Parent Asteroid (3200) Phaethon and In-Situ Analyses of Dust Accreting on the Earth Authors: Arai, T.; Kobayashi, M.; Ishibashi, K.; Yoshida, F.; Kimura, H.; Wada, K.; Senshu, H.; Yamada, M.; Okudaira, O.; Okamoto, T.; Kameda, S.; Srama, R.; Kruger, H.; Ishiguro, M.; Yabuta, H.; Nakamura, T.; Watanabe, J.; Ito, T.; Ohtsuka, K.; Tachibana, S.; Mikouchi, T.; Komatsu, M.; Nakamura-Messenger, K.; Sasaki, S.; Hiroi, T.; Abe, S.; Urakawa, S.; Hirata, N.; Demura, H.; Komatsu, G.; Noguchi, T.; Sekiguchi, T.; Inamori, T.; Yano, H.; Yoshikawa, M.; Ohtsubo, T.; Okada, T.; Iwata, T.; Nishiyama, K.; Toyota, T.; Kawakatsu, Y.; Takashima, T. Bibcode: 2018LPI....49.2570A Altcode: DESTINY+ is a flyby mission of asteroid Phaethon proposed for JAXA/ISAS Epsilon class small program with a launch target in 2022. Mission overview is presented. Title: Shock Vaporization and Post-Impact Chemistry in an Open System Without any Diaphragms Authors: Kurosawa, K.; Okamoto, T.; Yabuta, H.; Komatsu, G.; Matsui, T. Bibcode: 2018LPI....49.1960K Altcode: We developed a new experimental method for gas guns, which allows us to investigate shock vaporization in an open system without contaminations from the gun. Title: Telescopic CAmera for Phaethon (TCAP) and Multiband CAmera for Phaethon (MCAP) to be Installed on the DESTINY+ Spacecraft Authors: Ishibashi, K.; Kameda, S.; Kagitani, M.; Yamada, M.; Okudaira, O.; Okamoto, T.; Arai, T.; Yoshida, F.; Ishimaru, T.; Sato, S.; Takashima, T.; Iwata, T.; Okada, T. Bibcode: 2018LPI....49.2126I Altcode: Conceptual studies of the two cameras, a telescopic camera and a multiband camera, for the DESTINY+ mission, an asteroid flyby mission, have been carried out. Title: Super-strong Magnetic Field in Sunspots Authors: Okamoto, Takenori J.; Sakurai, Takashi Bibcode: 2018ApJ...852L..16O Altcode: 2017arXiv171208700O Sunspots are the most notable structure on the solar surface with strong magnetic fields. The field is generally strongest in a dark area (umbra), but sometimes stronger fields are found in non-dark regions, such as a penumbra and a light bridge. The formation mechanism of such strong fields outside umbrae is still puzzling. Here we report clear evidence of the magnetic field of 6250 G, which is the strongest field among Stokes I profiles with clear Zeeman splitting ever observed on the Sun. The field was almost parallel to the solar surface and located in a bright region sandwiched by two opposite-polarity umbrae. Using a time series of spectral data sets, we discuss the formation process of the super-strong field and suggest that this strong field region was generated as a result of compression of one umbra pushed by the horizontal flow from the other umbra, such as the subduction of the Earth’s crust in plate tectonics. Title: Scaling of Impact-Generated Cavity-Size for Highly Porous Targets and Its Application to Cometary Surfaces Authors: Okamoto, T.; Nakamura, A. M. Bibcode: 2017LPI....48.1817O Altcode: New scaling relations for targets with porosities larger than 30% were obtained and the results were applied for estimating crater dimensions on a comet. Title: Generation of Reduced Carbon Compounds by "Low" Velocity Impacts Authors: Ishibashi, K.; Kurosawa, K.; Okamoto, T.; Matsui, T. Bibcode: 2017LPI....48.2141I Altcode: Impact experiments with meteorite analogues at relatively low velocity (i.e., 6.5 km/s) generated a large amount of reductive gases species such as CH4. Title: Hydrocode Modeling of the Material Ejection by Spallation Authors: Kurosawa, K.; Okamoto, T.; Genda, H. Bibcode: 2017LPI....48.1855K Altcode: The launch of high-speed lightly-shocked ejecta was investigated. We found that the ejection velocity can exceed the upper limit in the shock physics. Title: Dust Sensor with a Large Detection Area Using Polyimide Film for Martian Moons Exploration Authors: Kobayashi, M.; Okudaira, O.; Kurosawa, K.; Okamoto, T.; Senshu, H.; Wada, K.; Sasaki, S.; Kimura, H.; Nakamura, M. Bibcode: 2017LPI....48.2342K Altcode: This is about a concept of a science instrument for discovery of martian dust ring. The instrument is one of payloads of Martian Moons Exploration by JAXA. Title: Helical Motions of Fine-structure Prominence Threads Observed by Hinode and IRIS Authors: Okamoto, Takenori J.; Liu, Wei; Tsuneta, Saku Bibcode: 2016ApJ...831..126O Altcode: 2016arXiv160800123O Fine-structure dynamics in solar prominences holds critical clues to understanding their physical nature of significant space-weather implications. We report evidence of rotational motions of horizontal helical threads in two active-region prominences observed by the Hinode and/or Interface Region Imaging Spectrograph satellites at high resolution. In the first event, we found transverse motions of brightening threads at speeds up to 55 km s-1 seen in the plane of the sky. Such motions appeared as sinusoidal space-time trajectories with a typical period of ∼390 s, which is consistent with plane-of-sky projections of rotational motions. Phase delays at different locations suggest the propagation of twists along the threads at phase speeds of 90-270 km s-1. At least 15 episodes of such motions occurred in two days, none associated with an eruption. For these episodes, the plane-of-sky speed is linearly correlated with the vertical travel distance, suggestive of a constant angular speed. In the second event, we found Doppler velocities of 30-40 km s-1 in opposite directions in the top and bottom portions of the prominence, comparable to the plane-of-sky speed. The moving threads have about twice broader line widths than stationary threads. These observations, when taken together, provide strong evidence for rotations of helical prominence threads, which were likely driven by unwinding twists triggered by magnetic reconnection between twisted prominence magnetic fields and ambient coronal fields. Title: Dust Sensor with Large Detection Area Using Polyimide Film and Piezoelectric Elements Authors: Kobayashi, M.; Okudaira, O.; Kurosawa, K.; Okamoto, T.; Matsui, T. Bibcode: 2016LPICo1980.4047K Altcode: We describe the development of dust particles sensor in space with large area (1m × 1m scale). The sensor has just a thin film of polyimide attached with small tips of piezoelectric elements. We performed experiments to characterize the sensor. Title: Joint SDO and IRIS Observations of a Novel, Hybrid Prominence-Coronal Rain Complex Authors: Liu, Wei; Antolin, Patrick; Sun, Xudong; Gao, Lijia; Vial, Jean-Claude; Gibson, Sarah; Okamoto, Takenori; Berger, Thomas; Uitenbroek, Han; De Pontieu, Bart Bibcode: 2016usc..confE..99L Altcode: Solar prominences and coronal rain are intimately related phenomena, both involving cool material at chromospheric temperatures within the hot corona and both playing important roles as part of the return flow of the chromosphere-corona mass cycle. At the same time, they exhibit distinct morphologies and dynamics not yet well understood. Quiescent prominences consist of numerous long-lasting, filamentary downflow threads, while coronal rain is more transient and falls comparably faster along well-defined curved paths. We report here a novel, hybrid prominence-coronal rain complex in an arcade-fan geometry observed by SDO/AIA and IRIS, which provides new insights to the underlying physics of such contrasting behaviors. We found that the supra-arcade fan region hosts a prominence sheet consisting of meandering threads with broad line widths. As the prominence material descends to the arcade, it turns into coronal rain sliding down coronal loops with line widths 2-3 times narrower. This contrast suggests that distinct local plasma and magnetic conditions determine the fate of the cool material, a scenario supported by our magnetic field extrapolations from SDO/HMI. Specifically, the supra-arcade fan (similar to those in solar flares; e.g., McKenzie 2013) is likely situated in a current sheet, where the magnetic field is weak and the plasma-beta could be close to unity, thus favoring turbulent flows like those prominence threads. In contrast, the underlying arcade has a stronger magnetic field and most likely a low-beta environment, such that the material is guided along magnetic field lines to appear as coronal rain. We will discuss the physical implications of these observations beyond prominence and coronal rain. Title: VizieR Online Data Catalog: New Numerical Galaxy Catalog (nu2GC) (Makiya+, Authors: Makiya, R.; Enoki, M.; Ishiyama, T.; Kobayashi, M. A. R.; Nagashima, M.; Okamoto, T.; Okoshi, K.; Oogi, T.; Shirakata, H. Bibcode: 2016yCat.100680025M Altcode: The mock galaxy catalog calculated by the nu2-GC model descri the paper.

File light-cone_nu2gc-H2.dat contains the galaxies having B-band apparent magnitude brighter than 28 [AB mag] and located at the redshift range 0<z<20.0, with 1 deg2 aperture.

We also provide "box-type" mock galaxy catalogs, catalognu2gc-Lz**.dat, that contain the simulated galaxies in the 1.123 (Gpc/h)3 size box at redshift z = 0.0, 0.48, 1.01, 1.97, 2.95, 6.97. For each simulated galaxy, redshift, comoving distance, stellar mass, gas mass, black hole mass, star formation rate, metallicity, and magnitude in B-, V-, SDSS-rp and 2MASS-Ks bands are given.

Terms of Use : When you write papers using these catalogs, we would be very grateful if you could refer the following two papers: Ishiyama et al., 2015PASJ...67...61I, Makiya et al., 2016PASJ...68...25M.

(7 data files). Title: Novel diffraction gratings for next generation spectrographs with high spectral dispersion Authors: Ebizuka, N.; Okamoto, T.; Hosobata, T.; Yamagata, Y.; Sasaki, M.; Uomoto, M.; Shimatsu, T.; Sato, S.; Hashimoto, N.; Tanaka, I.; Hattori, T.; Ozaki, S.; Aoki, W. Bibcode: 2016SPIE.9912E..2ZE Altcode: As a transmission grating, a surface-relief (SR) grating with sawtooth shaped ridges and volume phase holographic (VPH) grating are widely used for instruments of astronomical observations. However the SR grating is difficult to achieve high diffraction efficiency at high angular dispersion, and the VPH grating has low diffraction efficiency in high diffraction orders. We propose novel gratings that solve these problems. We introduce the hybrid grism which combines a high refractive index prism with a replicated transmission grating, which has sawtooth shaped ridges of an acute apex angle. The birefringence VPH (B-VPH) grating which contains an anisotropic medium, such as a liquid crystal, achieves diffraction efficiency up to 100% at the first diffraction order for natural polarization and for circular polarization. The quasi-Bragg (QB) grating which consists of long rectangular mirrors aligned in parallel precisely, like a window blind, achieves diffraction efficiency of 60% or more in higher than the 4th diffraction order. The volume binary (VB) grating with narrow grooves also achieves diffraction efficiency of 60% or more in higher than the 6th diffraction order. The reflector facet transmission (RFT) grating which is a SR grating with sawtooth shaped ridges of an acute apex angle achieves diffraction efficiency up to 80% in higher than the 4th diffraction order. Title: Ultra-High-Speed Imaging of the Impact Ejecta: Comparison with a SPH Simulation Authors: Okamoto, T.; Kurosawa, K.; Genda, H.; Matsui, T. Bibcode: 2016LPI....47.2515O Altcode: We conducted impact experiments to investigate the high-speed ejecta from near the impact point, comparing the results with those of SPH simulations. Title: Shock Vaporization of Water Ice in an Open System Investigated Using a Two-Stage Light Gas Gun Authors: Kurosawa, K.; Okamoto, T.; Yabuta, H.; Komatsu, G.; Matsui, T. Bibcode: 2016LPI....47.1838K Altcode: We constructed a new experimental system to investigate shock vaporization and post-impact chemistry of icy materials. Title: Laboratory Simulation of Shooting Star by Using a Two-Stage Light Gas Gun Authors: Senshu, H.; Kurosawa, K.; Okamoto, T.; Matsui, T. Bibcode: 2016LPI....47.2142S Altcode: We conducted a experimental study to simulate shooting stars in the laboratory. We successfully obtained spectroscopic data of the simulated shooting stars. Title: Resonant Absorption of Transverse Oscillations and Associated Heating in a Solar Prominence. II. Numerical Aspects Authors: Antolin, P.; Okamoto, T. J.; De Pontieu, B.; Uitenbroek, H.; Van Doorsselaere, T.; Yokoyama, T. Bibcode: 2015ApJ...809...72A Altcode: 2015arXiv150609108A Transverse magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere and may be responsible for generating the Sun’s million-degree outer atmosphere. However, direct evidence of the dissipation process and heating from these waves remains elusive. Through advanced numerical simulations combined with appropriate forward modeling of a prominence flux tube, we provide the observational signatures of transverse MHD waves in prominence plasmas. We show that these signatures are characterized by a thread-like substructure, strong transverse dynamical coherence, an out-of-phase difference between plane-of-the-sky motions and line-of-sight velocities, and enhanced line broadening and heating around most of the flux tube. A complex combination between resonant absorption and Kelvin-Helmholtz instabilities (KHIs) takes place in which the KHI extracts the energy from the resonant layer and dissipates it through vortices and current sheets, which rapidly degenerate into turbulence. An inward enlargement of the boundary is produced in which the turbulent flows conserve the characteristic dynamics from the resonance, therefore guaranteeing detectability of the resonance imprints. We show that the features described in the accompanying paper through coordinated Hinode and Interface Region Imaging Spectrograph observations match the numerical results well. Title: Resonant Absorption of Transverse Oscillations and Associated Heating in a Solar Prominence. I. Observational Aspects Authors: Okamoto, Takenori J.; Antolin, Patrick; De Pontieu, Bart; Uitenbroek, Han; Van Doorsselaere, Tom; Yokoyama, Takaaki Bibcode: 2015ApJ...809...71O Altcode: 2015arXiv150608965O Transverse magnetohydrodynamic waves have been shown to be ubiquitous in the solar atmosphere and can, in principle, carry sufficient energy to generate and maintain the Sun’s million-degree outer atmosphere or corona. However, direct evidence of the dissipation process of these waves and subsequent heating has not yet been directly observed. Here we report on high spatial, temporal, and spectral resolution observations of a solar prominence that show a compelling signature of so-called resonant absorption, a long hypothesized mechanism to efficiently convert and dissipate transverse wave energy into heat. Aside from coherence in the transverse direction, our observations show telltale phase differences around 180° between transverse motions in the plane-of-sky and line-of-sight velocities of the oscillating fine structures or threads, and also suggest significant heating from chromospheric to higher temperatures. Comparison with advanced numerical simulations support a scenario in which transverse oscillations trigger a Kelvin-Helmholtz instability (KHI) at the boundaries of oscillating threads via resonant absorption. This instability leads to numerous thin current sheets in which wave energy is dissipated and plasma is heated. Our results provide direct evidence for wave-related heating in action, one of the candidate coronal heating mechanisms. Title: The impact of dust in host galaxies on quasar luminosity functions. Authors: Shirakata, H.; Okamoto, T.; Enoki, M.; Nagashima, M.; Kobayashi, M. A. R.; Ishiyama, T.; Makiya, R. Bibcode: 2015MNRAS.450L...6S Altcode: 2014arXiv1412.1478S We have investigated effects of dust attenuation on quasar luminosity functions at z ∼ 2 using a semi-analytic galaxy formation model combined with a large cosmological N-body simulation. We estimate the dust attenuation of quasars self-consistently with that of galaxies by considering the dust in their host bulges. We find that the luminosity of the bright quasars is strongly dimmed by the dust attenuation, ∼2 mag in the B-band. Assuming the empirical bolometric corrections for active galactic nuclei (AGNs) by Marconi et al., we find that this dust attenuation is too strong to explain the B-band and X-ray quasar luminosity functions simultaneously. We consider two possible mechanisms that weaken the dust attenuation. As such a mechanism, we introduce a time delay for AGN activity, that is, gas fuelling to a central black hole starts sometime after the beginning of the starburst induced by a major merger. The other is the anisotropy in the dust distribution. We find that in order to make the dust attenuation of the quasars negligible, either the gas accretion into the black holes has to be delayed at least three times the dynamical time-scale of their host bulges or the dust covering factor is as small as ∼0.1. Title: First High-resolution Spectroscopic Observations of an Erupting Prominence Within a Coronal Mass Ejection by the Interface Region Imaging Spectrograph (IRIS) Authors: Liu, Wei; De Pontieu, Bart; Vial, Jean-Claude; Title, Alan M.; Carlsson, Mats; Uitenbroek, Han; Okamoto, Takenori J.; Berger, Thomas E.; Antolin, Patrick Bibcode: 2015ApJ...803...85L Altcode: 2015arXiv150204738L Spectroscopic observations of prominence eruptions associated with coronal mass ejections (CMEs), although relatively rare, can provide valuable plasma and three-dimensional geometry diagnostics. We report the first observations by the Interface Region Imaging Spectrograph mission of a spectacular fast CME/prominence eruption associated with an equivalent X1.6 flare on 2014 May 9. The maximum plane-of-sky and Doppler velocities of the eruption are 1200 and 460 km s-1, respectively. There are two eruption components separated by ∼200 km s-1 in Doppler velocity: a primary, bright component and a secondary, faint component, suggesting a hollow, rather than solid, cone-shaped distribution of material. The eruption involves a left-handed helical structure undergoing counterclockwise (viewed top-down) unwinding motion. There is a temporal evolution from upward eruption to downward fallback with less-than-free-fall speeds and decreasing nonthermal line widths. We find a wide range of Mg ii k/h line intensity ratios (less than ∼2 expected for optically-thin thermal emission): the lowest ever reported median value of 1.17 found in the fallback material, a comparably high value of 1.63 in nearby coronal rain, and intermediate values of 1.53 and 1.41 in the two eruption components. The fallback material exhibits a strong (\gt 5σ ) linear correlation between the k/h ratio and the Doppler velocity as well as the line intensity. We demonstrate that Doppler dimming of scattered chromospheric emission by the erupted material can potentially explain such characteristics. Title: First High-resolution Spectroscopic Observations by IRIS of a Fast, Helical Prominence Eruption Associated with a Coronal Mass Ejection Authors: Liu, W.; De Pontieu, B.; Okamoto, T. J.; Vial, J. C.; Title, A. M.; Antolin, P.; Berger, T. E.; Uitenbroek, H. Bibcode: 2014AGUFMSH11D..04L Altcode: High-resolution spectroscopic observations of prominence eruptions and associated coronal mass ejections (CMEs) are rare but can provide valuable plasma and energy diagnostics. New opportunities have recently become available with the advent of the Interface Region Imaging Spectrograph (IRIS) mission equipped with high resolution of 0.33-0.4 arcsec in space and 1 km/s in velocity, together with the Hinode Solar Optical Telescope of 0.2 arcsec spatial resolution. We report the first result of joint IRIS-Hinode observations of a spectacular prominence eruption occurring on 2014-May-09. IRIS detected a maximum redshift of 450 km/s, which, combined with the plane-of-sky speed of 800 km/s, gives a large velocity vector of 920 km/s at 30 degrees from the sky plane. This direction agrees with the source location at 30 degrees behind the limb observed by STEREO-A and indicates a nearly vertical ejection. We found two branches of redshifts separated by 200 km/s appearing in all strong lines at chromospheric to transition-region temperatures, including Mg II k/h, C II, and Si IV, suggesting a hollow, rather than solid, cone in the velocity space of the ejected material. Opposite blue- and redshifts on the two sides of the prominence exhibit corkscrew variations both in space and time, suggestive of unwinding rotations of a left-handed helical flux rope. Some erupted material returns as nearly streamline flows, exhibiting distinctly narrow line widths (~10 km/s), about 50% of those of the nearby coronal rain at the apexes of coronal loops, where the rain material is initially formed out of cooling condensation. We estimate the mass and kinetic energy of the ejected and returning material and compare them with those of the associated CME. We will discuss the implications of these observations for CME initiation mechanisms. Title: Experimental investigation for cavity dimensions of highly porous small bodies Authors: Okamoto, T.; Nakamura, A.; Hasegawa, S. Bibcode: 2014acm..conf..393O Altcode: Small bodies were probably very porous during the formation of the solar system. In order to understand the surface evolution of highly porous bodies, it is necessary to investigate the impact process for targets with such high porosity. In this study, impact experiments with sintered glass-bead targets of 87 and 94 % porosities were conducted. Growth of cavities with time and the final cavity dimensions were analyzed and compared with previous studies of porous targets.

Impact experiments were conducted using a two-stage light-gas gun at ISAS, Japan. The projectiles of a few millimeters were composed of titanium, aluminum, nylon, and basalt. The impact velocities ranged from 1.8 to 7.2 km s^{-1}. In order to observe the inside of the targets, we used a flash X-ray system and a micro-X-ray tomography instrument.

The track shape was found to be divided into two types, elongated 'carrot' shape and short 'bulb' shape [1]. The figures on the left and right present a transmission image of the bulb shape track and a sketch of a cross section of the cavity, respectively. The results of the final maximum diameter, D_max and the final entrance-hole diameter, D_ent show that both dimensions tend to increase with impact velocity and decrease with target porosity. We adopted the scaling law of crater diameter [2] for our analysis of D_max and D_ent. The following empirical relations are obtained for targets with porosity ≥ 87 %:

{D_max}/{d_p}(ρ_t/ρ_p)^{0.4} =10^{-1.52±0.27} ({Y}/ρ_t{v_0^2})^{-0.49 ± 0.07},

{D_ent}/{d_p}(ρ_t/ρ_p)^{0.4} =10^{-2.12±0.39} ({Y}/ρ_t{v_0^2})^{-0.53 ± 0.11},

where d_p, ρ_t, ρ_p, Y, and v_0 are the projectile diameter, target density, projectile density, target compressive strength, and the impact velocity, respectively. The results of the depth from the entrance hole to the maximum diameter of the cavity, L_max, shows that L_max decreases with impact velocity and increases with target porosity. If we assume that a projectile decelerates by inertial drag [1], the characteristic length L_0, which is the depth from the surface where the kinetic energy of the projectile becomes 1/e of the initial energy, is described as follows:

L_0={2ρ_p}/{3C_dρ_t}d_p,

where C_d is the drag coefficient that increases with dynamic pressure normalized by tensile strength of the projectile [1]. We found that L_max/d_p increases with L_0/d_p. It indicates that L_max depends on the degree of projectile deformation or disruption through the drag coefficient and also depends on the projectile-target density ratio. We will also discuss the growth of the cavity volume, maximum diameter, and depth of the cavity with time using dimensionless parameters of crater scaling [3]. Title: The Interface Region Imaging Spectrograph (IRIS) Authors: De Pontieu, B.; Title, A. M.; Lemen, J. R.; Kushner, G. D.; Akin, D. J.; Allard, B.; Berger, T.; Boerner, P.; Cheung, M.; Chou, C.; Drake, J. F.; Duncan, D. W.; Freeland, S.; Heyman, G. F.; Hoffman, C.; Hurlburt, N. E.; Lindgren, R. W.; Mathur, D.; Rehse, R.; Sabolish, D.; Seguin, R.; Schrijver, C. J.; Tarbell, T. D.; Wülser, J. -P.; Wolfson, C. J.; Yanari, C.; Mudge, J.; Nguyen-Phuc, N.; Timmons, R.; van Bezooijen, R.; Weingrod, I.; Brookner, R.; Butcher, G.; Dougherty, B.; Eder, J.; Knagenhjelm, V.; Larsen, S.; Mansir, D.; Phan, L.; Boyle, P.; Cheimets, P. N.; DeLuca, E. E.; Golub, L.; Gates, R.; Hertz, E.; McKillop, S.; Park, S.; Perry, T.; Podgorski, W. A.; Reeves, K.; Saar, S.; Testa, P.; Tian, H.; Weber, M.; Dunn, C.; Eccles, S.; Jaeggli, S. A.; Kankelborg, C. C.; Mashburn, K.; Pust, N.; Springer, L.; Carvalho, R.; Kleint, L.; Marmie, J.; Mazmanian, E.; Pereira, T. M. D.; Sawyer, S.; Strong, J.; Worden, S. P.; Carlsson, M.; Hansteen, V. H.; Leenaarts, J.; Wiesmann, M.; Aloise, J.; Chu, K. -C.; Bush, R. I.; Scherrer, P. H.; Brekke, P.; Martinez-Sykora, J.; Lites, B. W.; McIntosh, S. W.; Uitenbroek, H.; Okamoto, T. J.; Gummin, M. A.; Auker, G.; Jerram, P.; Pool, P.; Waltham, N. Bibcode: 2014SoPh..289.2733D Altcode: 2014arXiv1401.2491D; 2014SoPh..tmp...25D The Interface Region Imaging Spectrograph (IRIS) small explorer spacecraft provides simultaneous spectra and images of the photosphere, chromosphere, transition region, and corona with 0.33 - 0.4 arcsec spatial resolution, two-second temporal resolution, and 1 km s−1 velocity resolution over a field-of-view of up to 175 arcsec × 175 arcsec. IRIS was launched into a Sun-synchronous orbit on 27 June 2013 using a Pegasus-XL rocket and consists of a 19-cm UV telescope that feeds a slit-based dual-bandpass imaging spectrograph. IRIS obtains spectra in passbands from 1332 - 1358 Å, 1389 - 1407 Å, and 2783 - 2834 Å, including bright spectral lines formed in the chromosphere (Mg II h 2803 Å and Mg II k 2796 Å) and transition region (C II 1334/1335 Å and Si IV 1394/1403 Å). Slit-jaw images in four different passbands (C II 1330, Si IV 1400, Mg II k 2796, and Mg II wing 2830 Å) can be taken simultaneously with spectral rasters that sample regions up to 130 arcsec × 175 arcsec at a variety of spatial samplings (from 0.33 arcsec and up). IRIS is sensitive to emission from plasma at temperatures between 5000 K and 10 MK and will advance our understanding of the flow of mass and energy through an interface region, formed by the chromosphere and transition region, between the photosphere and corona. This highly structured and dynamic region not only acts as the conduit of all mass and energy feeding into the corona and solar wind, it also requires an order of magnitude more energy to heat than the corona and solar wind combined. The IRIS investigation includes a strong numerical modeling component based on advanced radiative-MHD codes to facilitate interpretation of observations of this complex region. Approximately eight Gbytes of data (after compression) are acquired by IRIS each day and made available for unrestricted use within a few days of the observation. Title: Outcome of impact disruption of iron meteorites at room temperature Authors: Katsura, T.; Nakamura, A.; Takabe, A.; Okamoto, T.; Sangen, K.; Hasegawa, S.; Liu, X.; Mashimo, T. Bibcode: 2014acm..conf..255K Altcode: The iron meteorites and some M-class asteroids are generally understood to originate in the cores of differentiated planetesimals or in the local melt pools of primitive bodies. On these primitive bodies and planetesimals, a wide range of collisional events at different mass scales, temperatures, and impact velocities would have occurred. Iron materials have a brittle-ductile transition at a certain temperature, which depends on metallurgical factors such as grain size and purity, and on conditions such as strain-rate and confining pressure [1]. An evolutional scenario of iron meteorite parent bodies was proposed in which they formed in the terrestrial planet region, after which they were scattered into the main belt by collisions, Yarkovsky thermal forces, and resonances [2]. In this case, they may have experienced collisional evolution in the vicinity of the Earth before they were scattered into the main belt. The size distribution of iron bodies in the main belt may therefore have depended on the disruption threshold of iron bodies at temperature above the brittle-ductile transition.

This paper presents the results of impact-disruption experiments of iron meteorite and steel specimens mm-cm in size as projectiles or targets conducted at room temperature using three light-gas guns and one powder gun. Our iron specimens were almost all smaller in size than their counterparts (as targets or projectiles, respectively). The fragment size distribution of iron material was different from that of rocks. In iron fragmentation, a higher percentage of the mass is concentrated in larger fragments, i.e., the mass fraction of fine fragments is much less than that of rocks shown in the Figure (left). This is probably due to the ductile nature of the iron materials at room temperature. Furthermore, the Figure (right) shows that the largest fragment mass fraction f is dependent not only on the energy density but also on the size of the specimens. In order to obtain a generalized empirical relationship for f, we assumed a power-law dependence of f on initial peak pressure P_0 normalized by a dynamic strength, Y, which was defined to be dependent on the size of the iron material. A least-squares fit to the data of iron meteorite specimens resulted in the following relationship: f∝ ({P_0}/{Y})^{-2.1}. The deformation of the iron materials was found to be most significant when the initial pressure greatly exceeded the dynamic strength of the material. Title: ALMA Will Determine the Spectroscopic Redshift z > 8 with FIR [O III] Emission Lines Authors: Inoue, A. K.; Shimizu, I.; Tamura, Y.; Matsuo, H.; Okamoto, T.; Yoshida, N. Bibcode: 2014ApJ...780L..18I Altcode: 2013arXiv1312.0684I We investigate the potential use of nebular emission lines in the rest-frame far-infrared (FIR) for determining spectroscopic redshift of z > 8 galaxies with the Atacama Large Millimeter/submillimeter Array (ALMA). After making a line emissivity model as a function of metallicity, especially for the [O III] 88 μm line which is likely to be the strongest FIR line from H II regions, we predict the line fluxes from high-z galaxies based on a cosmological hydrodynamics simulation of galaxy formation. Since the metallicity of galaxies reaches at ~0.2 Z ⊙ even at z > 8 in our simulation, we expect the [O III] 88 μm line as strong as 1.3 mJy for 27 AB objects, which is detectable at a high significance by <1 hr integration with ALMA. Therefore, the [O III] 88 μm line would be the best tool to confirm the spectroscopic redshifts beyond z = 8. Title: Study on the Triggering Process of Solar Flares Based on Hinode/SOT Observations Authors: Bamba, Y.; Kusano, K.; Yamamoto, T. T.; Okamoto, T. J. Bibcode: 2013ApJ...778...48B Altcode: 2013arXiv1309.5465B We investigated four major solar flare events that occurred in active regions NOAA 10930 (2006 December 13 and 14) and NOAA 11158 (2011 February 13 and 15) by using data observed by the Solar Optical Telescope on board the Hinode satellite. To reveal the trigger mechanism of solar flares, we analyzed the spatio-temporal correlation between the detailed magnetic field structure and the emission image of the Ca II H line at the central part of flaring regions for several hours prior to the onset of the flares. In all the flare events, we observed that the magnetic shear angle in the flaring regions exceeded 70°, as well as that characteristic magnetic disturbances developed at the centers of flaring regions in the pre-flare phase. These magnetic disturbances can be classified into two groups depending on the structure of their magnetic polarity inversion lines; the so-called opposite-polarity and reversed-shear magnetic field recently proposed by our group, although the magnetic disturbance in one event of the four samples is too subtle to clearly recognize the detailed structure. The result suggests that some major solar flares are triggered by rather small magnetic disturbances. We also show that the critical size of the flare-trigger field varies among flare events and briefly discuss how the flare-trigger process depends on the evolution of active regions. Title: Penetration Depth of Dust Grains into Highly Porous Primitive Bodies Authors: Okamoto, T.; Nakamura, A. M.; Hasegawa, S.; Kurosawa, K.; Ikezaki, K.; Tsuchiyama, A. Bibcode: 2013LPI....44.1824O Altcode: 2013LPICo1719.1824O To investigate the penetration depth of dust into small primitive bodies, we conducted impact experiments and obtained a deceleration model of dust penetration. Title: Calibrating an updated smoothed particle hydrodynamics scheme within gcd+ Authors: Kawata, D.; Okamoto, T.; Gibson, B. K.; Barnes, D. J.; Cen, R. Bibcode: 2013MNRAS.428.1968K Altcode: 2012MNRAS.tmp..115K; 2009arXiv0902.4002K We adapt a modern scheme of smoothed particle hydrodynamics (SPH) to our tree N-body/SPH galactic chemodynamics code gcd+. The applied scheme includes implementations of the artificial viscosity switch and artificial thermal conductivity proposed by Morris & Monaghan, Rosswog & Price and Price to model discontinuities and Kelvin-Helmholtz instabilities more accurately. We first present hydrodynamics test simulations and contrast the results to runs undertaken without artificial viscosity switch or thermal conduction. In addition, we also explore the different levels of smoothing by adopting larger or smaller smoothing lengths, i.e. a larger or smaller number of neighbour particles, Nnb. We demonstrate that the new version of gcd+ is capable of modelling Kelvin-Helmholtz instabilities to a similar level as the mesh code, athena. From the Gresho vortex, point-like explosion and self-similar collapse tests, we conclude that setting the smoothing length to keep Nnb as high as ∼58 is preferable to adopting smaller smoothing lengths. We present our optimized parameter sets from the hydrodynamics tests. Title: Laboratory experiments on crater scaling-law for sedimentary rocks in the strength regime Authors: Suzuki, A.; Hakura, S.; Hamura, T.; Hattori, M.; Hayama, R.; Ikeda, T.; Kusuno, H.; Kuwahara, H.; Muto, Y.; Nagaki, K.; Niimi, R.; Ogata, Y.; Okamoto, T.; Sasamori, T.; Sekigawa, C.; Yoshihara, T.; Hasegawa, S.; Kurosawa, K.; Kadono, T.; Nakamura, A. M.; Sugita, S.; Arakawa, M. Bibcode: 2012JGRE..117.8012S Altcode: 2012JGRE..11708012S We systematically conducted impact cratering experiments with sedimentary rocks at 0.8-7.1 km/s using various projectiles with 1.1-15 g/cm3 in density. The crater diameter, depth, and volume are investigated and compared with the results for igneous rocks. Then, using the non-dimensional parameters, the normalized crater diameter πD, the normalized depth πd, the normalized volume πV, the target strength per specific energy π3, and the target and projectile density ratio π4, the scaling laws, πD = (1.43 ± 0.25)π3-0.22±0.02 π40.11±0.07, πd = (0.22 ± 0.04)π3-0.25±0.02 π40.01±0.05, and πV = (0.11 ± 0.04) π3-0.71±0.05 π40.23±0.17, are obtained. The comparison with the results of igneous rocks suggests that the characteristic properties of sedimentary rocks such as the lower strength and the strong shock wave attenuation rate are actually effective for the cratering of sedimentary rocks. Title: The Aquila comparison project: the effects of feedback and numerical methods on simulations of galaxy formation Authors: Scannapieco, C.; Wadepuhl, M.; Parry, O. H.; Navarro, J. F.; Jenkins, A.; Springel, V.; Teyssier, R.; Carlson, E.; Couchman, H. M. P.; Crain, R. A.; Dalla Vecchia, C.; Frenk, C. S.; Kobayashi, C.; Monaco, P.; Murante, G.; Okamoto, T.; Quinn, T.; Schaye, J.; Stinson, G. S.; Theuns, T.; Wadsley, J.; White, S. D. M.; Woods, R. Bibcode: 2012MNRAS.423.1726S Altcode: 2011arXiv1112.0315S; 2012MNRAS.tmp.2970S We compare the results of various cosmological gas-dynamical codes used to simulate the formation of a galaxy in the Λ cold dark matter structure formation paradigm. The various runs (13 in total) differ in their numerical hydrodynamical treatment [smoothed particle hydrodynamics (SPH), moving mesh and adaptive mesh refinement] but share the same initial conditions and adopt in each case their latest published model of gas cooling, star formation and feedback. Despite the common halo assembly history, we find large code-to-code variations in the stellar mass, size, morphology and gas content of the galaxy at z= 0, due mainly to the different implementations of star formation and feedback. Compared with observation, most codes tend to produce an overly massive galaxy, smaller and less gas rich than typical spirals, with a massive bulge and a declining rotation curve. A stellar disc is discernible in most simulations, although its prominence varies widely from code to code. There is a well-defined trend between the effects of feedback and the severity of the disagreement with observed spirals. In general, models that are more effective at limiting the baryonic mass of the galaxy come closer to matching observed galaxy scaling laws, but often to the detriment of the disc component. Although numerical convergence is not particularly good for any of the codes, our conclusions hold at two different numerical resolutions. Some differences can also be traced to the different numerical techniques; for example, more gas seems able to cool and become available for star formation in grid-based codes than in SPH. However, this effect is small compared to the variations induced by different feedback prescriptions. We conclude that state-of-the-art simulations cannot yet uniquely predict the properties of the baryonic component of a galaxy, even when the assembly history of its host halo is fully specified. Developing feedback algorithms that can effectively regulate the mass of a galaxy without hindering the formation of high angular momentum stellar discs remains a challenge. Title: Flows and dynamics in prominences and cavities Authors: Okamoto, Takenori Joten Bibcode: 2012shin.confE.212O Altcode: In this talk, we will introduce a peculiar phenomenon, a slowly-rising column of cool material from the lower atmosphere in quiescent prominence observations by the Solar Optical Telescope aboard Hinode. The apparent ascent speed of the column is 2 km/s, while the fine structures of the column exhibit much faster motion of up to 20 km/s. The column eventually becomes a faint low-lying prominence. Interestingly, an overlying coronal cavity associated with the appearance of the column seen in the X-ray and EUV moves upward at 5 km/s. We investigated the relationship between these episodes and suggest that they are due to the emergence of a helical flux rope that undergoes reconnection with lower coronal fields, possibly carrying material into the coronal cavity. Under the assumption of the emerging flux scenario, the lower velocity of 2 km/s and the higher one of 20 km/s in the column are attributed to the rising motion of the emerging flux and to the outflow driven by magnetic reconnection between the emerging flux and the pre-existing coronal field, respectively. Our presentation gives a coherent explanation of the enigmatic phenomenon of the rising column with the emergence of the helical rope and its effect on the corona. Here we would like to discuss our suggestion and another possibility to explain this phenomenon, and consider how to perform good observations to connect activities in small and large scales in the future. Title: Experimental Study of Momentum Transfer Efficiency for High Porosity Targets Authors: Aoki, T.; Nakamura, A. M.; Okamoto, T.; Hasegawa, S. Bibcode: 2012LPICo1667.6207A Altcode: We performed impact experiments of high porosity targets in order to study momentum transfer efficiency. It was found from analysis of high-speed camera images that the ejecta carry a few tens % of the projectile momentum. Title: Laboratory Penetration Experiments of High Velocity Projectiles into Very Porous Targets on Exotic Origin of Dusts in Primitive Bodies Authors: Okamoto, T.; Nakamura, A. M.; Hasegawa, S.; Kurosawa, K.; Ikezaki, K.; Tsuchiyama, A. Bibcode: 2012LPICo1667.6065O Altcode: To understand dusts penetration into high porous bodies, we conducted impact experiments at velocities of 2-7 km/s into high-porosity targets of 80-90% porosity.Our results indicate that dusts can only be captured at the surface of small bodies. Title: Emergence of Twisted Flux in Prominence Observations Authors: Okamoto, T. J.; Tsuneta, S.; Berger, T. E.; Lites, B. W. Bibcode: 2012ASPC..455..123O Altcode: The emergence of twisted flux is a key process for supply of magnetic flux into the corona as well as solar dynamic activities such as sunspot formation and trigger of coronal mass ejections. In particular, there are numerous discussions about the role and necessity of twisted flux emergence for origin of prominences. However, the difficulty to measure vector magnetic fields has not allowed us to investigate the detailed relationship between emerging twisted flux and prominence. Hinode has changed the situation. The Spectro-Polarimeter aboard Hinode has high sensitivity to weaker magnetic fields of fine structures, and provides opportunities to detect weak horizontal magnetic fields. As a result, we have obtained signatures of twisted flux emergence associated with prominences: The observational features are "broadening and narrowing of a region dominated by horizontal magnetic field" and "rotating direction of horizontal field" on the photosphere. Moreover, the data show the interaction between the emerging twisted flux and granules, and that the flux rope has high intrinsic strength 650 G, while the flux density is as low as 100 G. Theoretical research with numerical simulation on the basis of these results is active. In addition, we investigate activities of a coronal cavity overlying a prominence on the limb, and suggest the existence of twisted flux rope to explain the activities of prominence and the coronal cavity comprehensively. Here we introduce both these observational and theoretical results, and discuss the details about emerging twisted flux. Title: Laboratory Impact Study on Velocity of the Fastest Ejecta from Porous Small Bodies Authors: Nakamura, A. M.; Okamoto, T.; Kiyomizu, K.; Aoki, T.; Nagaoka, H.; Hasegawa, S. Bibcode: 2012LPICo1667.6337N Altcode: We conducted laboratory impact experiments in order to study velocity filed of ejecta from porous targets with porosity of 40-94 %. We showed the fastest ejecta velocity depends on porosity and impact velocity and much lower than those of rocks. Title: Capture of Hypervelocity Dusts by Highly Porous Small Bodies Authors: Okamoto, T.; Nakamura, A. M.; Hasegawa, S.; Kurosawa, K.; Ikezaki, K.; Tsuchiyama, A. Bibcode: 2012LPI....43.1782O Altcode: We conducted dust impact experiments into highly porous brittle targets using a flash X-ray system and showed that the deceleration process of projectiles and the cavity morphology is similar to those reported for aerogel targets. Title: The baryons in the Milky Way satellites Authors: Parry, O. H.; Eke, V. R.; Frenk, C. S.; Okamoto, T. Bibcode: 2012MNRAS.419.3304P Altcode: 2011MNRAS.tmp.1998P; 2011arXiv1105.3474P We investigate the formation and evolution of satellite galaxies using smoothed particle hydrodynamics (SPH) simulations of a Milky Way (MW) like system, focusing on the best resolved examples, analogous to the classical MW satellites. Comparing with a pure dark matter simulation, we find that the condensation of baryons has had a relatively minor effect on the structure of the satellites' dark matter haloes. The stellar mass that forms in each satellite agrees relatively well over three levels of resolution (a factor of ∼64 in particle mass) and scales with (sub)halo mass in a similar way in an independent semi-analytical model. Our model provides a relatively good match to the average luminosity function of the MW and M31. To establish whether the potential wells of our satellites are realistic, we measure their masses within observationally determined half-light radii, finding that they have somewhat higher mass-to-light ratios than those derived for the MW dSphs from stellar kinematic data; the most massive examples are most discrepant. A statistical test yields an ∼6 per cent probability that the simulated and observationally derived distributions of masses are consistent. If the satellite population of the MW is typical, our results could imply that feedback processes not properly captured by our simulations have reduced the central densities of subhaloes, or that they initially formed with lower concentrations, as would be the case, for example, if the dark matter were made of warm, rather than cold particles. Title: You Cannot Press Out the Black Hole Authors: Ida, D.; Okamoto, T. Bibcode: 2012PThPh.127..163I Altcode: 2011arXiv1105.6173I It is shown that a ball-shaped black hole region homeomorphic with D^n cannot be pressed out, along whichever axis penetrating the black hole region, into a black ring with a doughnut-shaped black hole region homeomorphic with S^1 × D^{n-1}. A more general prohibition law for the change of the topology of black holes, including a version of no-bifurcation theorems for black holes, is given. Title: Generation and propagation of Alfvenic waves in spicules Authors: De Pontieu, B.; Okamoto, T. J.; Rouppe van der Voort, L.; Hansteen, V. H.; Carlsson, M. Bibcode: 2011AGUFMSH13B1956D Altcode: Both spicules and Alfven waves have recently been implicated in playing a role in the heating of the outer atmosphere. Yet we do not know how spicules or Alfven waves are generated. Here we focus on the properties of Alfvenic waves in spicules and their role in forming spicules. We use high-resolution observations taken with the Solar Optical Telescope onboard Hinode, and with the CRISP Fabry-Perot Interferometer at the Swedish Solar Telescope (SST) in La Palma to study the generation and propagation of Alfvenic waves in spicules and their disk counterparts. Using automated detection algorithms to identify propagating waves in limb spicules, we find evidence for both up- and downward propagating as well as standing waves. Our data suggests significant reflection of waves in and around spicules and provides constraints for theoretical models of spicules and wave propagation through the chromosphere. We also show observational evidence (using SST data) of the generation of Alfven waves and the role they play in forming spicules. Title: Temporary capture of asteroids by Jupiter/Saturn Authors: Higuchi, A.; Okamoto, T.; Ida, S. Bibcode: 2011epsc.conf.1832H Altcode: 2011DPS....43.1832H Irregular satellites observed around giant planets are thought to be object that were initially in the heliocentric orbits and later been captured into their current orbits around their host planets. To clarify the possibility of their origin in the asteroid belt, we calculated the orbit of mass-less particles initially distributed around the outer asteroid belt under the perturbations by Jupiter and Saturn. We found that the asteroids can be the candidates for the irregular satellites, not only of Jupiter but also of Saturn. Title: Propagating Waves Along Spicules Authors: Okamoto, Takenori J.; De Pontieu, Bart Bibcode: 2011ApJ...736L..24O Altcode: 2011arXiv1106.4270O Alfvénic waves are thought to play an important role in coronal heating and acceleration of solar wind. Here we investigate the statistical properties of Alfvénic waves along spicules (jets that protrude into the corona) in a polar coronal hole using high-cadence observations of the Solar Optical Telescope on board Hinode. We developed a technique for the automated detection of spicules and high-frequency waves. We detected 89 spicules and found (1) a mix of upward propagating, downward propagating, as well as standing waves (occurrence rates of 59%, 21%, and 20%, respectively); (2) the phase speed gradually increases with height; (3) upward waves dominant at lower altitudes, standing waves at higher altitudes; (4) standing waves dominant in the early and late phases of each spicule, while upward waves were dominant in the middle phase; (5) in some spicules, we find waves propagating upward (from the bottom) and downward (from the top) to form a standing wave in the middle of the spicule; and (6) the medians of the amplitude, period, and velocity amplitude were 55 km, 45 s, and 7.4 km s-1, respectively. We speculate that upward propagating waves are produced near the solar surface (below the spicule) and downward propagating waves are caused by reflection of (initially) upward propagating waves off the transition region at the spicule top. The mix of upward and downward propagating waves implies that exploiting these waves to perform seismology of the spicular environment requires careful analysis and may be problematic. Title: Lunar BroadBand Seismometer System in the Japanese lunar landing mission SELENE-2: its science goals and instrument details Authors: Shiraishi, H.; Kobayashi, N.; Takeuchi, N.; Murakami, H.; Lognonne, P.; Giardini, D.; Christensen, U. R.; Okamoto, T.; Kuge, K.; Zhao, D.; Mocquet, A.; Mimoun, D.; de Raucourt, S.; Nebut, T.; Tillier, S.; Kawamura, T.; Mance, D.; Zweifel, P.; Bierwirth, M.; Roll, R.; Ishihara, Y.; Araki, E.; Ogawa, K.; Yamada, R.; Shirai, K.; Iijima, Y.; Hayakawa, M.; Tanaka, S.; Kakuma, H.; Yamada, I. Bibcode: 2010AGUFM.U51B0039S Altcode: SELENE-2 is the first lunar landing mission of Japan. We are developing a broadband seismometer system as a powerful candidate for a payload instrument. In this paper, we demonstrate the necessity of broadband seismometer observation and its scientific targets. The Apollo projects in 1970's installed an equilateral triangle seismograph network at apexes where Apollo 12,14,15 and 16 landed. The passive seismic observation had lasted for over 7 years and it provided us with the first information on the lunar seismicity and the lunar structure down to a depth of 1,000km. It, however, had two drawbacks: (1) the size of the network is limited within 1,000km, and (2) the sensitivity of the seismometers with a limited narrow band of 0.17Hz is marginal to detect the small deep moonquakes which occurred frequently. In addition, due to the strong scattering of seismic waves, P and S wave arrivals could not be picked up accurately, and the typical picking error is up to 10sec. Because of these problems, the lunar velocity models obtained so far are less certain, in particular, at depths greater than 200km. In the SELENE-2 project we plan to have only one landing site and so we cannot run a seismic network observation by the project alone. Thus, we need to obtain more information from the feeble seismic waveforms using a broadband (0.02-50Hz) seismometer having 10 times higher sensitivity than that of the Apollo seismometers to overcome the drawback (2) as mentioned above. The characteristic frequency of the shallow layer is about 0.12Hz for the seismic velocity model of Nakamura(1981). Below that frequency, we expect clear detection of seismic phases reflected and converted at an internal discontinuity such as the core-mantle boundary. The long-period seismic waveforms may provide us not only information on the depth of an internal discontinuity but also seismic velocity contrast at the boundary. Another scientific target is to determine the corner frequency of deep moonquakes which can provide us information on the physical state in the source region. Although it was suggested that the corner frequency of deep moonquakes is much smaller than that of earthquakes, the result is not conclusive because of the narrow band of the Apollo seismometers. To realize the highly sensitive broadband seismic observation in a timely manner, we make use of the heritage of a short-period seismometer(SP) developed in the past Lunar-A project and a long-period broadband seismometer VBB(LP) developed in the ExoMars project. We customize these seismic sensors to work properly under the severe conditions at the lunar surface. The thermal shield module is the key technology to realize high performance in the seismic observation on the moon. Title: A rising cool column associated with formation of prominence and coronal cavity Authors: Okamoto, T. J.; Tsuneta, S.; Berger, T. E. Bibcode: 2010AGUFMSH51A1665O Altcode: A prominence consists of relatively cool chromospheric plasma found above the solar limb at coronal heights where the temperature and density are typically two order of magnitude higher and lower, respectively. Prominences are frequently associated with larger coronal structures known as coronal cavities. There are numerous observational studies on prominences with multi-wavelength and with high-spatial resolution and also on the relationship between cavities and coronal mass ejections, while less analyses on activities inside coronal cavities. Continuous observations were performed of a quiescent prominence with the Hinode satellite on 2006 December 23 and 24. In the Ca II H-line channel of the Solar Optical Telescope we observed a peculiar slowly-rising column of cool material from the lower atmosphere. The apparent ascent speed of the column is 2 km/s, while the fine structures of the column exhibit much faster motion of up to 20 km/s. The column eventually becomes a faint low-lying prominence. An overlying coronal cavity associated with the appearance of the column seen in the X-ray and EUV moves upward at 5 km/s. We discuss the relationship between these episodes and suggest that they are due to the emergence of a helical flux rope that undergoes reconnection with lower coronal fields, possibly carrying material into the coronal cavity. Under the assumption of the emerging flux scenario, the lower velocity of 2 km/s and the higher one of 20 km/s in the column are attributed to the rising motion of the emerging flux and to the outflow driven by magnetic reconnection between the emerging flux and the pre-existing coronal field, respectively. Our presentation gives a coherent explanation of the enigmatic phenomenon of the rising column with the emergence of the helical rope and its effect on the corona. Title: A Rising Cool Column as a Signature of Helical Flux Emergence and Formation of Prominence and Coronal Cavity Authors: Okamoto, Takenori J.; Tsuneta, Saku; Berger, Thomas E. Bibcode: 2010ApJ...719..583O Altcode: 2010arXiv1006.4633O Continuous observations were performed of a quiescent prominence with the Solar Optical Telescope on board the Hinode satellite on 2006 December 23 and 24. A peculiar slowly rising column of ~104 K plasma develops from the lower atmosphere during the observations. The apparent ascent speed of the column is 2 km s-1, while the fine structures of the column exhibit much faster motion of up to 20 km s-1. The column eventually becomes a faint low-lying prominence. An overlying coronal cavity associated with the appearance of the column seen in the X-ray and EUV moves upward at ~5 km s-1. We discuss the relationship between these episodes and suggest that they are due to the emergence of a helical flux rope that undergoes reconnection with lower coronal fields, possibly carrying material into the coronal cavity. Under the assumption of the emerging flux scenario, the lower velocity of 2 km s-1 and the higher one of 20 km s-1 in the column are attributed to the rising motion of the emerging flux and to the outflow driven by magnetic reconnection between the emerging flux and the pre-existing coronal field, respectively. The present paper gives a coherent explanation of the enigmatic phenomenon of the rising column with the emergence of the helical rope and its effect on the corona. We discuss the implications that the emergence of such a helical rope has on the dynamo process in the convection zone. Title: Emergence of Helical Flux and the Formation of an Active Region Filament Channel Authors: Lites, B. W.; Kubo, M.; Berger, T.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A.; Okamoto, T. J.; Otsuji, K. Bibcode: 2010ApJ...718..474L Altcode: We present comprehensive observations of the formation and evolution of a filament channel within NOAA Active Region (AR) 10978 from Hinode/Solar Optical Telescope and TRACE. We employ sequences of Hinode spectro-polarimeter maps of the AR, accompanying Hinode Narrowband Filter Instrument magnetograms in the Na I D1 line, Hinode Broadband Filter Instrument filtergrams in the Ca II H line and G-band, Hinode X-ray telescope X-ray images, and TRACE Fe IX 171 Å image sequences. The development of the channel resembles qualitatively that presented by Okamoto et al. in that many indicators point to the emergence of a pre-existing sub-surface magnetic flux rope. The consolidation of the filament channel into a coherent structure takes place rapidly during the course of a few hours, and the filament form then gradually shrinks in width over the following two days. Particular to this filament channel is the observation of a segment along its length of horizontal, weak (500 G) flux that, unlike the rest of the filament channel, is not immediately flanked by strong vertical plage fields of opposite polarity on each side of the filament. Because this isolated horizontal field is observed in photospheric lines, we infer that it is unlikely that the channel formed as a result of reconnection in the corona, but the low values of inferred magnetic fill fraction along the entire length of the filament channel suggest that the bulk of the field resides somewhat above the low photosphere. Correlation tracking of granulation in the G band presents no evidence for either systematic flows toward the channel or systematic shear flows along it. The absence of these flows, along with other indications of these data from multiple sources, reinforces (but does not conclusively demonstrate) the picture of an emerging flux rope as the origin of this AR filament channel. Title: Quiescent Prominence Dynamics Observed with the Hinode Solar Optical Telescope. I. Turbulent Upflow Plumes Authors: Berger, Thomas E.; Slater, Gregory; Hurlburt, Neal; Shine, Richard; Tarbell, Theodore; Title, Alan; Lites, Bruce W.; Okamoto, Takenori J.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Magara, Tetsuya; Suematsu, Yoshinori; Shimizu, Toshifumi Bibcode: 2010ApJ...716.1288B Altcode: Hinode/Solar Optical Telescope (SOT) observations reveal two new dynamic modes in quiescent solar prominences: large-scale (20-50 Mm) "arches" or "bubbles" that "inflate" from below into prominences, and smaller-scale (2-6 Mm) dark turbulent upflows. These novel dynamics are related in that they are always dark in visible-light spectral bands, they rise through the bright prominence emission with approximately constant speeds, and the small-scale upflows are sometimes observed to emanate from the top of the larger bubbles. Here we present detailed kinematic measurements of the small-scale turbulent upflows seen in several prominences in the SOT database. The dark upflows typically initiate vertically from 5 to 10 Mm wide dark cavities between the bottom of the prominence and the top of the chromospheric spicule layer. Small perturbations on the order of 1 Mm or less in size grow on the upper boundaries of cavities to generate plumes up to 4-6 Mm across at their largest widths. All plumes develop highly turbulent profiles, including occasional Kelvin-Helmholtz vortex "roll-up" of the leading edge. The flows typically rise 10-15 Mm before decelerating to equilibrium. We measure the flowfield characteristics with a manual tracing method and with the Nonlinear Affine Velocity Estimator (NAVE) "optical flow" code to derive velocity, acceleration, lifetime, and height data for several representative plumes. Maximum initial speeds are in the range of 20-30 km s-1, which is supersonic for a ~10,000 K plasma. The plumes decelerate in the final few Mm of their trajectories resulting in mean ascent speeds of 13-17 km s-1. Typical lifetimes range from 300 to 1000 s (~5-15 minutes). The area growth rate of the plumes (observed as two-dimensional objects in the plane of the sky) is initially linear and ranges from 20,000 to 30,000 km2 s-1 reaching maximum projected areas from 2 to 15 Mm2. Maximum contrast of the dark flows relative to the bright prominence plasma in SOT images is negative and ranges from -10% for smaller flows to -50% for larger flows. Passive scalar "cork movies" derived from NAVE measurements show that prominence plasma is entrained by the upflows, helping to counter the ubiquitous downflow streams in the prominence. Plume formation shows no clear temporal periodicity. However, it is common to find "active cavities" beneath prominences that can spawn many upflows in succession before going dormant. The mean flow recurrence time in these active locations is roughly 300-500 s (5-8 minutes). Locations remain active on timescales of tens of minutes up to several hours. Using a column density ratio measurement and reasonable assumptions on plume and prominence geometries, we estimate that the mass density in the dark cavities is at most 20% of the visible prominence density, implying that a single large plume could supply up to 1% of the mass of a typical quiescent prominence. We hypothesize that the plumes are generated from a Rayleigh-Taylor instability taking place on the boundary between the buoyant cavities and the overlying prominence. Characteristics, such as plume size and frequency, may be modulated by the strength and direction of the cavity magnetic field relative to the prominence magnetic field. We conclude that buoyant plumes are a source of quiescent prominence mass as well as a mechanism by which prominence plasma is advected upward, countering constant gravitational drainage. Title: Response of the Solar Atmosphere to the Emergence of `Serpentine' Magnetic Field Authors: Harra, L. K.; Magara, T.; Hara, H.; Tsuneta, S.; Okamoto, T. J.; Wallace, A. J. Bibcode: 2010SoPh..263..105H Altcode: Active region magnetic flux that emerges to the photosphere from below will show complexity in the structure, with many small-scale fragmented features appearing in between the main bipole and then disappearing. Some fragments seen will be absorbed into the main polarities and others seem to cancel with opposite magnetic field. In this paper we investigate the response of the corona to the behaviour of these small fragments and whether energy through reconnection will be transported into the corona. In order to investigate this we analyse data from the Hinode space mission during flux emergence on 1 - 2 December 2006. At the initial stages of flux emergence several small-scale enhancements (of only a few pixels size) are seen in the coronal line widths and diffuse coronal emission exists. The magnetic flux emerges as a fragmented structure, and coronal loops appear above these structures or close to them. These loops are large-scale structures - most small-scale features predominantly stay within the chromosphere or at the edges of the flux emergence. The most distinctive feature in the Doppler velocity is a strong ring of coronal outflows around the edge of the emerging flux region on the eastern side which is either due to reconnection or compression of the structure. This feature lasts for many hours and is seen in many wavelengths. We discuss the implications of this feature in terms of the onset of persistent outflows from an active region that could contribute to the slow solar wind. Title: Scattering Polarization in the Fe I 630 nm Emission Lines at the Extreme Limb of the Sun Authors: Lites, B. W.; Casini, R.; Manso Sainz, R.; Jurčák, J.; Ichimoto, K.; Ishikawa, R.; Okamoto, T. J.; Tsuneta, S.; Bellot Rubio, L. Bibcode: 2010ApJ...713..450L Altcode: Spectro-polarimetric observations with the Solar Optical Telescope onboard Hinode reveal the emission spectrum of the Fe I 630 nm lines at the solar limb. The emission shell extends for less than 1'' thereby making it extremely difficult to detect from ground-based observatories viewing the limb through the Earth's atmosphere. The linear polarization signal is clearly due to scattering and it is predominantly oriented in the radial direction. Using a comprehensive atomic model of iron, we are able to interpret qualitatively the observed signals, including the radial orientation of the linear polarization. The Hanle effect causes the linear polarization of the Fe I 630 nm lines to be sensitive to magnetic fields between ~0.1 G and ~40 G, and also to be sensitive to the field's topology for stronger fields. The overall degree of observed polarization can be reproduced by randomly oriented horizontal magnetic fields of strength ≈2 G. The discovery of their scattering polarization signals thus opens a new diagnostic opportunity for these lines. Title: Hinode/SOT Measurements of Flows and Waves in Solar Prominences Authors: Berger, Thomas; Okamoto, Takenori; Schmieder, Brigitte Bibcode: 2010cosp...38.2913B Altcode: 2010cosp.meet.2913B We review Hinode Solar Optical Telescope (SOT) measurements of flows and waves in quies-cent and active solar prominences. In quiescent prominences, Hinode/SOT observations have revealed a new mode of buoyant transport in the form of dark upflows that originate at the chromospheric base of the prominence. The upflows can take the form of large-scale (10 Mm) "bubbles" that rise through the entire prominence into the overlying coronal cavity, or they can take the form of numerous small-scale (1 Mm) plumes that generate from an apparent Rayleigh-Taylor instability on the boundary between the prominence and the impinging buoy-ant flow system. The episodic flows directly inject mass, magnetic flux, and helicity into the overlying coronal cavity, moving the system towards destabilization and eruption in the form of CMEs. Hinode/SOT quiescent prominence observations have also verified the existence of ubiquitous downflow streams and vortex flows confirming that prominences are far from magne-tostatic conditions. Tracking and doppler measurements of prominence downflows find speeds of 5-15 km s-1 and imply that the trajectories are not strictly vertical. Active region promi-nence studies find counter-streaming flows along horizontal magnetic field lines with velocities of 20-30 km s-1 ; upflows, downflow streams, and rotational flows have not been observed in these systems. Active Region prominence field lines exhibit transverse oscillations indicative of Alfv`n waves with periods of several minutes, amplitudes of 1 Mm, and wavelengths of 250 Mm or more. These properties are consistent with magnetic field strengths of 50 gauss or more at typical prominence density conditions and carry enough energy to heat the surrounding prominence/corona transition region (PCTR). Title: Small-scale oscillations in a quiescent prominence observed by HINODE/SOT. Prominence oscillations Authors: Ning, Z.; Cao, W.; Okamoto, T. J.; Ichimoto, K.; Qu, Z. Q. Bibcode: 2009A&A...499..595N Altcode: Context: Investigations of the behavior of small-scale threads can provide an alternative approach to studying prominence dynamics and understanding its origin and nature.
Aims: The behavior of threads are analyzed in a quiescent prominence, including drifting and both the horizontally and vertically oscillating motions. These indicate waves in the solar prominence.
Methods: We used the Hα images at a setting wavelength of +0.076 Å. A quiescent prominence was observed by HINODE/SOT on 2008 January 15 for about 3 h in total.
Results: Consistent with previous findings, prominences show numerous thread-like structures. Some threads clearly exhibit both vertically and horizontally oscillatory motions, while others are only drifting. Complicated cases show both drifting and oscillatory motions simultaneously. In the upper part of the prominence, the threads are oscillating independently of each other. We find that three threads oscillate with the same phase for at least two periods. The oscillations seem to be strongly damped since they disappear after a few periods. The maximum number of observed periods is 8 in our observations. In the lower part of the prominence, however, the different threads have a mixed character with the individual oscillatory motions unstable for one entire period. Most oscillatory motions will disappear after a half period or less, while the new oscillatory motions are excited nearby. A 5-min period is predominant, and the oscillating amplitudes show an average value of ±3.5 km s-1. We find some upflows in the spicule layer, and they appear to transport the mass from photosphere (or spicules themselves) to the prominence. These upflows have an average velocity amplitude of 0.8 km s-1.
Conclusions: The threads exhibit three distinct behaviors. The first is only drifting, the second is typically oscillating, and the third shows both characteristics. There are no substantial differences between the periods of horizontally and vertically oscillating threads in this prominence. Title: Waveform inversion for slip distribution of the 2006 Java tsunami earthquake by using 2.5D finite-difference Green's function Authors: Okamoto, T.; Takenaka, H. Bibcode: 2009EP&S...61E..17O Altcode: We first incorporate the large effect of near-source heterogeneity on teleseismic body waveforms in the inversion of the slip distribution of the 2006 Java tsunami earthquake. We incorporate the effect by computing the response of an assumed "2.5D" model structure of the Java trench by a 2.5D finite-difference method. Based on a simulation of inversion, we suggest that intense smearing is possible when we apply 1D Green's functions in the analysis, and that it may obscure the slip pattern. In the inversion of real data, we confirm macroscopic features, such as a long duration (∼165 s) and a slow rupture velocity (∼1.25 km/s). The region of the initial rupture is found to be isolated from the eastern broad region in which we further identify a heterogeneous slip distribution. Most of these regions are likely to be at the sedimentary plate interface where the accreted sediment and the subducting plate are in contact. In particular, the nearly ``isolated'' feature of a shallow slip region suggests a possible faulting in the shallowest part of the sedimentary plate interface without being strongly enforced by the rupture propagated from the deeper part of the fault. Such heterogeneity suggests a highly variable frictional behavior at the sedimentary plate interface. Title: Prominence Formation Associated with an Emerging Helical Flux Rope Authors: Okamoto, Takenori J.; Tsuneta, Saku; Lites, Bruce W.; Kubo, Masahito; Yokoyama, Takaaki; Berger, Thomas E.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Nagata, Shin'ichi; Shibata, Kazunari; Shimizu, Toshifumi; Shine, Richard A.; Suematsu, Yoshinori; Tarbell, Theodore D.; Title, Alan M. Bibcode: 2009ApJ...697..913O Altcode: 2009arXiv0904.0007O The formation and evolution process and magnetic configuration of solar prominences remain unclear. In order to study the formation process of prominences, we examine continuous observations of a prominence in NOAA AR 10953 with the Solar Optical Telescope on the Hinode satellite. As reported in our previous Letter, we find a signature suggesting that a helical flux rope emerges from below the photosphere under a pre-existing prominence. Here we investigate more detailed properties and photospheric indications of the emerging helical flux rope, and discuss their relationship to the formation of the prominence. Our main conclusions are: (1) a dark region with absence of strong vertical magnetic fields broadens and then narrows in Ca II H-line filtergrams. This phenomenon is consistent with the emergence of the helical flux rope as photospheric counterparts. The size of the flux rope is roughly 30,000 km long and 10,000 km wide. The width is larger than that of the prominence. (2) No shear motion or converging flows are detected, but we find diverging flows such as mesogranules along the polarity inversion line. The presence of mesogranules may be related to the emergence of the helical flux rope. (3) The emerging helical flux rope reconnects with magnetic fields of the pre-existing prominence to stabilize the prominence for the next several days. We thus conjecture that prominence coronal magnetic fields emerge in the form of helical flux ropes that contribute to the formation and maintenance of the prominence. Title: Effect of Near-Source Trench Structure on Teleseismic Body Waveforms: AN Application of a 2.5D Fdm to the Java Trench Authors: Okamoto, T.; Takenaka, H. Bibcode: 2009aogs...13..215O Altcode: We study strong effect of near-source structure on teleseismic body waveforms from two well-recorded aftershocks of the 2006 Java tsunami earthquake. We assume a two-dimensional, heterogeneous model of the Java trench structure on the basis of recent seismic surveys. We compute synthetic waveforms by an efficient "2.5-dimensional" (2.5D) finite-difference method. A "waveform relocation technique" which combines a non-linear inversion of source parameters with a grid search procedure is applied in order to correct possible systematic bias in hypocentral parameters. Simulation of inversion shows that the resolution of the source position obtained by using 2.5D Green's functions is better than that for 1D Green's functions. The synthetic waveforms obtained by the inversion of true data with 2.5D Green's functions reproduce well the observed large later phases, and retrieved moment tensors are similar to those of Global CMT. Thus, the effect of the near-source structure can be reproduced by 2.5D model, and with the 2.5D synthetics we can obtain improved source parameters at the trench regions where only teleseismic data are available. Title: Chemical Abundance Patterns in the Local Dwarf Galaxies in the CDM Universe Authors: Nagashima, M.; Okamoto, T. Bibcode: 2008ASPC..399..475N Altcode: We present chemical properties of dwarf galaxies in a semi-analytic galaxy formation model. We find a good match with observations of the Local dwarf spheroidals. The supernova feedback is a key to understanding the different metal abundances of the Local Group dwarf spheroidals from those associated with the Milky Way. Title: High Resolution Observations of Spicules with Hinode/SOT Authors: Suematsu, Y.; Ichimoto, K.; Katsukawa, Y.; Shimizu, T.; Okamoto, T.; Tsuneta, S.; Tarbell, T.; Shine, R. A. Bibcode: 2008ASPC..397...27S Altcode: High time cadence unprecedented images at the limb with Ca II H line filtergraph from the Solar Optical Telescope (SOT) aboard Hinode have revealed that a spicule consists of highly dynamic multi-threads (typically twin) as thin as a few tenths of an arcsecond, and shows prominent lateral movement or oscillation with rotation on its axis during its life. This multi-thread structure and lateral motion indicate that the spicules can be driven by magnetic reconnection at unresolved spatial scales at their footpoints. Title: Galaxy Formation Authors: Okamoto, T. Bibcode: 2008ASPC..393..111O Altcode: 2007arXiv0712.0086O I review the current status of theoretical studies of galaxy formation. I outline the importance of the physics of baryonic component in galaxy formation by showing results obtained by using two major tools, semi-analytical approaches and cosmological simulations. In particular, I emphasize the role of feedback in galaxy formation and discuss whether apparent conflicts between the standard theory of structure formation, the cold dark matter model, and observations can be solved by the feedback. I also discuss future prospects in numerical simulations of galaxy formation. Title: Giant Chromospheric Anemone Jet Observed with Hinode and Comparison with Magnetohydrodynamic Simulations: Evidence of Propagating Alfvén Waves and Magnetic Reconnection Authors: Nishizuka, N.; Shimizu, M.; Nakamura, T.; Otsuji, K.; Okamoto, T. J.; Katsukawa, Y.; Shibata, K. Bibcode: 2008ApJ...683L..83N Altcode: 2008arXiv0810.3384N Hinode discovered a beautiful giant jet with both cool and hot components at the solar limb on 2007 February 9. Simultaneous observations by the Hinode SOT, XRT, and TRACE 195 Å satellites revealed that hot (~5 × 106 K) and cool (~104 K) jets were located side by side and that the hot jet preceded the associated cool jet (~1-2 minutes). A current-sheet-like structure was seen in optical (Ca II H), EUV (195 Å), and soft X-ray emissions, suggesting that magnetic reconnection is occurring in the transition region or upper chromosphere. Alfvén waves were also observed with Hinode SOT. These propagated along the jet at velocities of ~200 km s-1 with amplitudes (transverse velocity) of ~5-15 km s-1 and a period of ~200 s. We performed two-dimensional MHD simulation of the jets on the basis of the emerging flux-reconnection model, by extending Yokoyama and Shibata's model. We extended the model with a more realistic initial condition (~106 K corona) and compared our model with multiwavelength observations. The improvement of the coronal temperature and density in the simulation model allowed for the first time the reproduction of the structure and evolution of both the cool and hot jets quantitatively, supporting the magnetic reconnection model. The generation and the propagation of Alfvén waves are also reproduced self-consistently in the simulation model. Title: Emerging Helical Flux Rope Associated with Prominence Formation Observed by Hinode Authors: Okamoto, Takenori Bibcode: 2008AstHe.101..385O Altcode: The new Japan/US/UK solar physics satellite Hinode enables the highest resolution imaging of prominences as yet seen with a temporal uniformity that allows long-hours of diffraction-limited movies and a capability of photospheric vector magnetic field measurements. The author investigates formation and evolution processes of active-region prominences with the Solar Optical Telescope observations. Here a discovery about emergence of a helical flux rope associated with prominence formation is reported and the property of the helical flux rope is discussed. Title: Emergence of a helical flux rope and prominence formation Authors: Okamoto, T. J.; Tsuneta, S.; Lites, B. W.; Kubo, M.; Yokoyama, T.; Berger, T. E.; Ichimoto, K.; Katsukawa, Y.; Nagata, S.; Shibata, K.; Shimizu, T.; Shine, R. A.; Suematsu, Y.; Tarbell, T. D.; Title, A. M. Bibcode: 2008AGUSMSP43B..06O Altcode: We report a discovery about emergence of a helical flux rope. The episode may be related to the formation and evolution of an active region prominence. Statistical studies by previous authors indicate that numerous prominences have the inverse-polarity configuration suggesting the helical magnetic configurations. There are two theoretical models about formation of such a coronal helical magnetic field in association with prominences: flux rope model and sheared-arcade model. We have so far no clear observational evidence to support either model. In order to find a clue about the formation of the prominence, we had continuous observations of NOAA AR 10953 with the SOT during 2007 April 28 to May 9. A prominence was located over the polarity inversion line in the south-east of the main sunspot. These observations provided us with a time series of vector magnetic fields on the photosphere under the prominence. We found four new features: (1) The abutting opposite-polarity regions on the two sides along the polarity inversion line first grew laterally in size and then narrowed. (2) These abutting regions contained vertically-weak, but horizontally-strong magnetic fields. (3) The orientations of the horizontal magnetic fields along the polarity inversion line on the photosphere gradually changed with time from a normal- polarity configuration to an inverse-polarity one. (4) The horizontal-magnetic field region was blueshifted. These indicate that helical flux rope emerges from below the photosphere into the corona along the polarity inversion line under the prominence. We suggest that this supply of a helical magnetic flux possibly into the corona is related to formation and maintenance of active-region prominences. Title: Hinode SOT Observations of Solar Quiescent Prominence Dynamics Authors: Berger, Thomas E.; Shine, Richard A.; Slater, Gregory L.; Tarbell, Theodore D.; Title, Alan M.; Okamoto, Takenori J.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Suematsu, Yoshinori; Tsuneta, Saku; Lites, Bruce W.; Shimizu, Toshifumi Bibcode: 2008ApJ...676L..89B Altcode: We report findings from multihour 0.2'' resolution movies of solar quiescent prominences (QPs) observed with the Solar Optical Telescope (SOT) on the Hinode satellite. The observations verify previous findings of filamentary downflows and vortices in QPs. SOT observations also verify large-scale transverse oscillations in QPs, with periods of 20-40 minutes and amplitudes of 2-5 Mm. The upward propagation speed of several waves is found to be ~10 km s-1, comparable to the sound speed of a 10,000 K plasma, implying that the waves are magnetoacoustic in origin. Most significantly, Hinode SOT observations reveal that dark, episodic upflows are common in QPs. The upflows are 170-700 km in width, exhibit turbulent flow, and rise with approximately constant speeds of ~20 km s-1 from the base of the prominence to heights of ~10-20 Mm. The upflows are visible in both the Ca II H-line and Hα bandpasses of SOT. The new flows are seen in about half of the QPs observed by SOT to date. The dark upflows resemble buoyant starting plumes in both their velocity profile and flow structure. We discuss thermal and magnetic mechanisms as possible causes of the plumes. Title: Emergence of a Helical Flux Rope under an Active Region Prominence Authors: Okamoto, Takenori J.; Tsuneta, Saku; Lites, Bruce W.; Kubo, Masahito; Yokoyama, Takaaki; Berger, Thomas E.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Nagata, Shin'ichi; Shibata, Kazunari; Shimizu, Toshifumi; Shine, Richard A.; Suematsu, Yoshinori; Tarbell, Theodore D.; Title, Alan M. Bibcode: 2008ApJ...673L.215O Altcode: 2008arXiv0801.1956O Continuous observations were obtained of NOAA AR 10953 with the Solar Optical Telescope (SOT) on board the Hinode satellite from 2007 April 28 to May 9. A prominence was located over the polarity inversion line (PIL) to the southeast of the main sunspot. These observations provided us with a time series of vector magnetic fields on the photosphere under the prominence. We found four features: (1) The abutting opposite-polarity regions on the two sides along the PIL first grew laterally in size and then narrowed. (2) These abutting regions contained vertically weak but horizontally strong magnetic fields. (3) The orientations of the horizontal magnetic fields along the PIL on the photosphere gradually changed with time from a normal-polarity configuration to an inverse-polarity one. (4) The horizontal magnetic field region was blueshifted. These indicate that helical flux rope was emerging from below the photosphere into the corona along the PIL under the preexisting prominence. We suggest that this supply of a helical magnetic flux to the corona is associated with evolution and maintenance of active region prominences. Title: Giant chromospheric jet observed with Hinode and magnetic reconnection model Authors: Nishizuka, Naoto; Shimizu, Masaki; Nakamura, Tahei; Otsuji, Kenichi; Okamoto, Takenori; Shibata, Kazunari; Katsukawa, Yukio Bibcode: 2008cosp...37.2239N Altcode: 2008cosp.meet.2239N Heating of the solar chromosphere and corona is one of the long-standing puzzles in astronomy and also a key to understand the Sun-Earth connection through solar wind and EUV/X-ray radiation. A solar space telescope mission Hinode revealed that solar chromosphere is much more dynamic than had been thought and is full of tiny jets, which may be a key to resolve the puzzle of chromospheric and coronalheating. It has long been observed that H-alpha jets called surges often occur in the chromosphere. They have been believed to be produced by magnetic reconnection, which is an energy conversion mechanism from magnetic energy into thermal and kinetic energies of plasma when anti-parallel magnetic fields encounter and reconnect with each other. Hinode's new chromospheric observations (with Calcium II H broad band filter) revealed that jets are ubiquitous in the chromosphere and some of the jets show evidence of magnetic reconnection. However, there have not been simultaneous observations of the chromospheric jets at X-ray, EUV, and Optical (at Calcium II H line) wavelengths until now. Here we report first multi-wavelength observations of a chromospheric jet with Solar Optical Telescope (SOT) and X-Ray Telescope (XRT) on board Hinode and TRACE 195A filter. With its unprecedented high quality instruments at both optical and X-rays, Hinode discovered a beautiful, giant jet with both cool (104 K) and hot (5x106 K) components at the solar limb. TRACE satellite also observed the same jet with EUV telescope and revealed the existence of both hot (106 K) and cool (unknown temperature) components. These data set are probably the best multi-wavelength observations of solar jets until now. We also performed magnetohydrodynamic simulation of the jet based on the reconnection model and found that it can explain various observational facts very well. It has often been argued that some of solar jets are produced by magnetic reconnection, but previous observations had a limitation on spatial and temporal resolutions and temperature coverage. Using these new data and twodimensional magnetohydrodynamic simulations of the jet, we showed, for the first time, how hot and cool jets are heated and accelerated during the reconnection, including associated generation of Alfvén waves. This jet formation dynamics would show a proto-tyep of reconnection e model of solar jets and can be applied for other small jets discovered by Hinode, which might heat the chromosphere and corona. Title: Chromospheric Anemone Jets as Evidence of Ubiquitous Reconnection Authors: Shibata, Kazunari; Nakamura, Tahei; Matsumoto, Takuma; Otsuji, Kenichi; Okamoto, Takenori J.; Nishizuka, Naoto; Kawate, Tomoko; Watanabe, Hiroko; Nagata, Shin'ichi; UeNo, Satoru; Kitai, Reizaburo; Nozawa, Satoshi; Tsuneta, Saku; Suematsu, Yoshinori; Ichimoto, Kiyoshi; Shimizu, Toshifumi; Katsukawa, Yukio; Tarbell, Theodore D.; Berger, Thomas E.; Lites, Bruce W.; Shine, Richard A.; Title, Alan M. Bibcode: 2007Sci...318.1591S Altcode: 2008arXiv0810.3974S The heating of the solar chromosphere and corona is a long-standing puzzle in solar physics. Hinode observations show the ubiquitous presence of chromospheric anemone jets outside sunspots in active regions. They are typically 3 to 7 arc seconds = 2000 to 5000 kilometers long and 0.2 to 0.4 arc second = 150 to 300 kilometers wide, and their velocity is 10 to 20 kilometers per second. These small jets have an inverted Y-shape, similar to the shape of x-ray anemone jets in the corona. These features imply that magnetic reconnection similar to that in the corona is occurring at a much smaller spatial scale throughout the chromosphere and suggest that the heating of the solar chromosphere and corona may be related to small-scale ubiquitous reconnection. Title: Hinode SOT observations of plume upflows and cascading downflows in quiescent solar prominences Authors: Berger, T.; Shine, R.; Slater, G.; Tarbell, T.; Title, A.; Lites, B.; Tsuneta, S.; Okamoto, T. J.; Ichimoto, K.; Katsukawa, Y.; Sekii, T.; Suematsu, Y.; Shimizu, T. Bibcode: 2007AGUFMSH53A1065B Altcode: We present several Hinode SOT filtergram movies of quiescent solar prominences that show newly discovered "plume-like" upflows and cascading "waterfall-like" downflows that persist for the entire multi-hour duration of the observations. The flow speeds are on the order of 10 km/sec with typical widths of 400-700 km. Preliminary calculations show that if the upflows are buoyancy driven, the associated thermal perturbation is on the order of 10,000 K, sufficient to explain the dark appearance of the upflows in the interference filter passbands. In addition we observe rotational vortices and body oscillations within the prominences. These new observations challenge current magnetostatic models of solar prominences by showing that prominence plasmas are in constant motion, often in directions perpendicular to the magnetic field lines proposed by the models. TRACE, Hinode/EIS, and Hinode/XRT observations are used to investigate the differential topology of the flows across temperature regimes. Title: Coronal Transverse Magnetohydrodynamic Waves in a Solar Prominence Authors: Okamoto, T. J.; Tsuneta, S.; Berger, T. E.; Ichimoto, K.; Katsukawa, Y.; Lites, B. W.; Nagata, S.; Shibata, K.; Shimizu, T.; Shine, R. A.; Suematsu, Y.; Tarbell, T. D.; Title, A. M. Bibcode: 2007Sci...318.1577O Altcode: 2008arXiv0801.1958O Solar prominences are cool 104 kelvin plasma clouds supported in the surrounding 106 kelvin coronal plasma by as-yet-undetermined mechanisms. Observations from Hinode show fine-scale threadlike structures oscillating in the plane of the sky with periods of several minutes. We suggest that these represent Alfvén waves propagating on coronal magnetic field lines and that these may play a role in heating the corona. Title: Triggering Mechanism for the Filament Eruption on 2005 September 13 in NOAA Active Region 10808 Authors: Nagashima, Kaori; Isobe, Hiroaki; Yokoyama, Takaaki; Ishii, Takako T.; Okamoto, Takenori J.; Shibata, Kazunari Bibcode: 2007ApJ...668..533N Altcode: 2007arXiv0706.3519N On 2005 September 13 a filament eruption accompanied by a halo coronal mass ejection (CME) occurred in the most flare-productive active region, NOAA 10808, in solar cycle 23. Using multiwavelength observations before the filament eruption on September 13, we investigate the processes leading to the catastrophic eruption. We find that the filament slowly ascended at a speed of 0.1 km s-1 over 2 days before the eruption. During slow ascension, many small flares were observed close to the footpoints of the filament, where new magnetic elements were emerging. On the basis of the observational facts, we discuss the triggering mechanism leading to the filament eruption. We suggest that the process toward the eruption is as follows. First, a series of small flares played a role in changing the topology of the loops overlying the filament. Second, the small flares gradually changed the equilibrium state of the filament and caused the filament to ascend slowly over 2 days. Finally, a C2.9 flare that occurred when the filament was close to the critical point for loss of equilibrium directly led to the catastrophic filament eruption right after it. Title: Examinations of the Relative Alignment of the Instruments on SOT Authors: Okamoto, T. J.; Katsukawa, Y.; Shimizu, T.; Ichimoto, K.; Suematsu, Y.; Tsuneta, S.; Tarbell, T. D. Bibcode: 2007ASPC..369...47O Altcode: We report the results of the examination about the relative alignment among the instruments on SOT. We employ a test data set obtained in the natural sun-light test in May 2005, which has had a grid pattern over the entire FOV. SOT has the filtergraph (FG) and the spectro-polarimeter (SP). The FG consists of six broadband filter imagers (BFI) and six narrowband filter imagers (NFI). We examined the displacements among the images taken with different filters to an accuracy of better than 0.1 pixel corresponding to 0.02''. It is important to know relative displacements and plate scales of these instruments for accurate alignment of observational data. We note that the values measured in our work are relative and it is needed to decide the absolute values with another way. Title: High Resolution Observation of Spicules in Ca II H with Hinode/SOT Authors: Suematsu, Yoshinori; Katsukawa, Y.; Ichimoto, K.; Tsuneta, S.; Okamoto, T.; Nagata, S.; Shimizu, T.; Tarbell, T.; Shine, R.; Title, A. Bibcode: 2007AAS...210.9411S Altcode: 2007BAAS...39..219S High cadence observation with a Ca II H broadband filtergraph (passband of 0.25 nm) of the Solar Optical Telescope (SOT) aboard HINODE has revealed dynamical nature of solar limb spicules. Thanks to a diffraction-limited and low-scattered light property of the instrument, we can track the detailed evolution of individual spicules for the first time with a spatial resolution of 0.2 arcsec. The spicules in Ca II H are typically several arcsec tall and have multi-thread structure; each threads are a few tenth of arcsec wide. It should be stressed that most spicules do not show a simple up-and-down motion along a rigid path line. They start with bright structure emanating from Ca II H bright region, get widen and diffused with time and ascent, showing expansion with lateral or even helical motion in tall events. Small and short lived spicules tend to fade out after ascent. We will present new findings of spicule dynamics in different magnetic environments and discuss about long standing controversy of its motion and evolution. Title: Discovery Of Cool Cloud-like Structures In The Corona With Hinode Solar Optical Telescope Authors: Okamoto, Takenori; Tsuneta, S.; Katsukawa, Y.; Ichimoto, K.; Suematsu, Y.; Shimizu, T.; Nagata, S.; Shibata, K.; Tarbell, T.; Shine, R.; Berger, T.; Lites, B.; Myers, D. Bibcode: 2007AAS...210.9426O Altcode: 2007BAAS...39..221O A solar observation satellite Hinode (Japanese for sun rise) was launched in September 2006.Hinode carried 3 advanced solar telescopes, visible light telescope, EUV imaging spectrometer, and X-ray telescope to simultaneously observe the photosphere, chromosphere, transition region, and corona. In the performance verification phase of the Hinode spacecraft with its telescopes, we observed an active region AR10921 near the west limb of the solar disk on November 9 2006. At this point, we planned to observe spicules on the limb with a broadband filter dedicated to Ca II H line (3968A). Ca II-H emission line (3968A) comes from plasma with temperature of approx. 10(4) K, which is much lower than the coronal temperature of 10(6-7) K. In addition to spectacular spicules, we find a large cloud-like structure located 10,000-20,000 km above the limb. The cloud has a very complex fine structure with dominant horizontal thread-like structure. Some features are moving horizontally and also have clear vertical oscillatory motions. The periods and amplitudes of these oscillations are 130-250 seconds and 200-850 km, respectively. The vertical oscillatory motion sometimes has a coherence length as long as 16,000 km. We conclude that from various observational features this vertical oscillation is a signature of Alfven waves propagating along the horizontal magnetic fields. We will discuss their origin and implications. Title: e-SpaceCam : Development of a Remote Cooperative Observation System for Telescopes with P2P(Peer-to-Peer) Agent Network Using Location Information Authors: Okamoto, T.; Kato, S. Bibcode: 2006IAUSS...2E.100O Altcode: Introduction. It is very important for astronomical study and observation to operate a telescope by oneself. However, there are various problems such as the cost and location to use the telescope. The most promising technology that solves those problems is a remote telescope system. However, an old and usual remote telescope system was Server & Client type system. Therefore, the remote telescope owners and the remote telescope users have to manage their telescope by themselves. Especially, enough knowledge of the network, the time and cost to control the telescopes are necessary for the remote telescope owners. So it is difficult for general telescope owners to offer their telescopes as remote telescopes. We are developing a new environment that manages the remote telescopes. The environment connects users who want to use telescopes with the telescopes connected with PC (RS232c, USB, etc) all over the world. Our goal is to develop an environment by which users are able to cooperate and to share a lot of telescopes and the observational data for the education and the observation. Methods. Our remote telescope system is established on the P2P agent network. Various agents execute tasks allocated instead of users. (to retrieve, to connect, to control, etc) So users needn't do irksome tasks. Our system mounts LL-Net (Location-based Logical Network). LL-Net can manage user nodes on the P2P network by a key made based on location information. Our system key is allocated by the longitude and latitude. Results and Discussion. Users can retrieve remote telescopes that suit them and connect with them. Telescope owners can make their telescopes remote telescopes without troublesome jobs. Logical network constructed with LL-Net enables telescopes which the user hoped to be retrieved efficiently. We investigate more suitable use of LL-Net for a remote telescope. We plan to realize to share the observational data and to make remote telescopes cooperate. Title: The metal enrichment of galaxies and galaxy clusters in the cold dark matter universe Authors: Nagashima, M.; Lacey, C. G.; Okamoto, T.; Baugh, C. M.; Frenk, C. S.; Cole, S. Bibcode: 2006AIPC..847..442N Altcode: We investigate the metal enrichment due to type II and Ia supernovae using semi-analytic models of galaxy formation based on the cold dark matter model of the Universe. Title: Simulations of SH wave scattering due to cracks by the 2-D finite difference method Authors: Suzuki, Y.; Kawahara, J.; Okamoto, T.; Miyashita, K. Bibcode: 2006EP&S...58..555S Altcode: We simulate SH wave scattering by 2-D parallel cracks using the finite difference method (FDM), instead of the popularly used boundary integral equation method (BIEM). Here special emphasis is put on simplicity; we apply a standard FDM (fourth-order velocity-stress scheme with a staggered grid) to media in cluding traction-freecracks, which are expressed by arrays of grid points with zero traction. Two types of accuracy tests based oncomparison with a reliable BIEM, suggest that the present method gives practically sufficient accuracy, except for the wavefields in the vicinity of cracks, which can be well handled if the second-order FDM is used instead. As an application of this method, we also simulate wave propagation in media with randomly distributed cracks of the same length. We experimentally determine the attenuation and velocity dispersion induced by scattering from the synthetic seismograms, using a waveform averaging technique. It is shown that the results are well explained by a theory based on the Foldy approximation for crack densities of up to about 01. The presence of a free surface does not affect the validity of the theory. A preliminary experiment also suggests that the validity will not change even for multi-scale cracks. Title: Filament Oscillations and Moreton Waves Associated with EIT Waves Authors: Okamoto, Takenori J.; Nakai, Hidekazu; Keiyama, Atsushi; Narukage, Noriyuki; UeNo, Satoru; Kitai, Reizaburo; Kurokawa, Hiroki; Shibata, Kazunari Bibcode: 2004ApJ...608.1124O Altcode: In this paper we compare EUV Imaging Telescope (EIT) waves with simultaneous phenomena seen in Hα in order to address the question of what an EIT wave is. We surveyed the events associated with solar flares larger than GOES M-class in 1999-2002. The Hα data are taken with the Flare-monitoring Telescope (FMT) at the Hida Observatory of Kyoto University. Among 14 simultaneous observations of EIT waves and Hα, 11 were found to have filament eruptions, three were associated with Moreton waves, and one was found to have only filament oscillations. This shows that we cannot see clear wave fronts in Hα even if EIT waves exist, but that it is possible to recognize invisible waves by means of filament oscillations. The nature of filament oscillations and Moreton waves associated with EIT waves is examined in detail, and it is found that the filament oscillations were caused by EIT waves. Title: Morphological Evolution of Cluster Galaxies Authors: Okamoto, T.; Nagashima, M. Bibcode: 2003RMxAC..17...98O Altcode: We investigate environmental effects on morphology evolution of bright cluster galaxies (L > L[*]) in a Lambda -dominated cold dark matter universe using a combination of N-body simulations and semi-analytic (SA) model. We normalize our model parameters to reproduce the properties of local galaxies, and then we study how ram pressure stripping (RPS) and small starburst triggered by a minor merger (minor burst) affect the morphologies of cluster galaxies. We find that the morphological fraction of galaxies with intermediate bulge-to-total luminosity ratios (B/Ts) cannot be reproduced and the effect of the RPS is negligible unless we consider the minor burst. Title: Cloud mass function in a gas rich dwarf galaxy Authors: Saitou, T.; Habe, A.; Okamoto, T. Bibcode: 2003IAUS..208..441S Altcode: No abstract at ADS Title: Substructure of Galaxy Clusters and Cosmological Constant Authors: Suwa, T.; Habe, A.; Yoshikawa, K.; Okamoto, T. Bibcode: 2003IAUS..208..447S Altcode: No abstract at ADS Title: Environmental Effects on Evolution of Cluster Galaxies Authors: Okamoto, T.; Nagashima, M. Bibcode: 2003IAUS..208..435O Altcode: No abstract at ADS Title: Full waveform moment tensor inversion by reciprocal finite difference Green's function Authors: Okamoto, T. Bibcode: 2002EP&S...54..715O Altcode: We study two important aspects of the waveform moment tensor inversion for the shallow earthquakes in the subduction region: the effect of the intense lateral inhomogeneity in the structure, and the strategy to invert the waveform data for the focal mechanisms. For the first aspect, using a forward finite difference modeling, we demonstrate that the effect of the inhomogeneity is quite large on the surface waves with a period of about 20s, and the current knowledge on the subduction region structure is practically effective in reproducing the characteristics in the observed waveforms. For the second aspect, we develop a reciprocal moment tensor inversion method that can generate the Green's functions for a large quantity of source locations (19,200 in this study) in a realistic inhomogeneous structure by only three finite difference calculations per a single station. The inversion with a grid search scheme result in a reasonable source location, moment tensor and fit of the waveforms using data from only two stations. The constraint on the epicenter in the "transverse" direction is found to be somewhat weak in the case of single-station inversions, but the two-station inversion improves the constraint. Title: Study of Multiphase Interstellar Matter in a Gas Rich Dwarf Galaxy Authors: Saitou, T.; Okamoto, T.; Habe, A. Bibcode: 2002aprm.conf..289S Altcode: Because of limitations in numerical resolution of cosmological galaxy formation simulations, previous studies can not consider multiphase structures of the ISM which should strongly affect galaxy properties. For instance, the size of disk galaxies formed in numerical simulations is smaller than that of observed galaxies.

In this study, by increasing the numerical resolution, we take into account the multiphase structure of ISM produced by radiative cooling, UV heating and supernova feedback. We simulate evolutions of multiphase ISM in a gas-rich dwarf galaxy, and obtain various aspects corresponding to gas-rich dwarf galaxies, especially, giant molecular cloud associations and superbubbles produced by subsequent supernovae.

The cloud mass function in our models has a power law form with index α ∼-1.7 which agrees well with the observed values α ∼ -1.5 to -2.0. The bubble size approximately corresponds to the scale height of a warm (103 K< T<104 K) disk.

Our numerical results show that feedback by SNe plays a very important role in regulation of ISM evolution in a gas-rich dwarf galaxy. Title: Properties of Galaxies in Rich Clusters Authors: Okamoto, T.; Nagashima, Masahiro Bibcode: 2001ASPC..222..149O Altcode: 2001pgf..conf..149O No abstract at ADS Title: Formation and evolution of galactic halos in a cluster of galaxies Authors: Habe, A.; Okamoto, T. Bibcode: 2000NuPhS..80C0907H Altcode: No abstract at ADS Title: Galaxy Distribution in Clusters of Galaxies Authors: Okamoto, T.; Yachi, S.; Habe, A. Bibcode: 1999IAUS..183..262O Altcode: beta-discrepancy have been pointed out from comparison of optical and X-ray observations of clusters of galaxies. To examine physical reason of beta-discrepancy, we use N-body simulation which contains two components, dark particles and galaxies which are identified by using adaptive-linking friend of friend technique at a certain red-shift. The gas component is not included here, since the gas distribution follows the dark matter distribution in dark halos (Jubio F. Navarro, Carlos S. Frenk and Simon D. M. White 1995). We find that the galaxy distribution follows the dark matter distribution, therefore beta-discrepancy does not exist, and this result is consistent with the interpretation of the beta-discrepancy by Bahcall and Lubin (1994), which was based on recent observation. Title: Formation and Evolution of Galactic Halos in Clusters of Galaxies Authors: Okamoto, T.; Habe, A. Bibcode: 1999ASSL..240...57O Altcode: 1999numa.conf...57O No abstract at ADS Title: Formation and evoluton of galactic halos in a cluster of galaxies Authors: Habe, A.; Okamoto, T. Bibcode: 1998tx19.confE.516H Altcode: We investigate time evolution both of a rich cluster of galaxies and its member galactic halos in the standard cold dark matter (SCDM) universe, using high resolution N-body simulations. In our numerical results, we find out several hundreds of galactic halos inside of the cluster's virial radius by using the adaptive friends-of-friends algorithm. A number of halos formed at higher redshift have been tidally disrupted till z = 0 in the cluster. Therefore we improve a method of deriving merging history trees of galaxies by taking account of tidally stripped galaxies. We find that at high redshift (z > 3), the fraction of merging galaxies in the cluster formation region is higher than that of the field. After z ~3, however, it rapidly decreases. The fraction of the strongly stripped galaxies in the cluster increases with time from z ~= 0.5. At z = 0 a clear correlation appears between the fraction and the distance from the center of the cluster. Title: Optical Spectra and Semi-Empirical Model of a White-Light Flare Authors: Ding, M. D.; Fang, C.; Gan, W. Q.; Okamoto, T. Bibcode: 1994ApJ...429..890D Altcode: We derive a semi-empirical atmospheric model for the 1979 September 19 white-light flare (WLF), based on the observed continuum at 3590 to 3990 A and the Ca II K line profile. The model has a strongly heated photosphere, but has a chromospheric structure within the range of ordinary flare models. According to this model, the white-light continuum is mainly produced by the H- emission in the photosphere. A negative Balmer jump appears in the continuum spectrum (without considering the line blanketing effect), due to the Balmer continuum absorption in the chromosphere. From the spectral features and model results, the traditional heating mechanisms that are proposed to transport the energy from the corona down to deep layers seem insufficient to fully explain the photospheric heating for this WLF. The heating energy may originate within the photosphere itself. The possible energy release processes are also discussed, but a satisfactory explanation needs further quantitative studies. Title: Doppler Shifts of Metallic Lines for a White-Light Flare Authors: Ding, M. D.; Fang, C.; Okamoto, T. Bibcode: 1994SoPh..149..143D Altcode: In this paper we investigate the Doppler shifts of the metallic lines for a 3B white-light flare on September 19, 1979. The results show that there is no systematic shift at the line center, while there may appear some asymmetry at the line wing. A possible heating process of this flare is proposed to interpret the observed spectral features. Title: Construction of magneto-otical filters and their application to solar observations. Authors: Miyazaki, H.; Sakurai, T.; Okamoto, T.; Ichimoto, K.; Miyashita, M.; Koyama, K.; Sakata, A.; Wada, S. Bibcode: 1993RNAOJ...2..417M Altcode: 1993RNOAJ...2..417M The magneto-optical filter (MOF) is made of a transparent cell placed in a strong magnetic field. The cell contains the vapor of material like sodium. By utilizing the magneto-optical effect near the wavelength of a spectral line, MOF provides a very narrow and stable passband, which is particularly suitable for helioseimological observations. The cell becomes less transparent as it ages, and can only be used in observations for several months. The authors' aim was to construct a filter that can be continuously used for several years without losing the sodium vapor at the cell wall. This was achieved by heating the whole cell to about 200°C. Title: Spectral analysis of the 3B flare on September 19, 1979: asymmetries and shifts of metallic lines Authors: Ding, Ming-de; Fang, Cheng; Okamoto, T. Bibcode: 1993ChA&A..17..413D Altcode: The asymmetries and Doppler shifts of metallic lines of the 3B flare on September 19, 1979 are investigated in this paper. The results show that: (1) red asymmetries dominate in strong metallic lines, but blue asymmetries also exist in some weak lines; (2) the maximum of the line asymmetry always precedes the maximum of the line intensity; (3) the blue asymmetry occurs generally in the early phase, and can occasionally turn to a red one in the later phase; and (4) the line center has no obvious shift, regardless of the line asymmetry. It is proposed that, the mass motions around the temperature minimum region caused by the impulsive heating or the propagation of the chromospheric condensation can explain these observational results. The study on metallic lines has an auxiliary help for understanding the dynamic process in the lower atmosphere of solar flares. Title: Spectral analysis of the 3B flare on September 19, 1979: asymmetry and Doppler shift of the metal lines. Authors: Ding, Mingde; Fang, Cheng; Okamoto, T. Bibcode: 1993AcApS..13..245D Altcode: The asymmetry and Doppler shift of metal lines of the 3B flare on September 19, 1979 are investigated. The results show that: (1) red asymmetries dominate in strong metal lines, but blue asymmetries also exist in some weak lines; (2) the maximum of the line asymmetry always precedes the maximum of the line intensity; (3) the blue asymmetry occurs generally in the early phase and can turn to a red one in the later phase; and (4) the line center has no obvious shift, regardless of the line asymmetry. It is proposed that the mass motions around the temperature minimum region caused by the impulsive heating or the propagation of the chromospheric condensation can explain these observational results. The study on metal lines can help understanding the dynamic process in the lower atmosphere of solar flares. Title: Solar Flare Telescope project. Authors: Ichimoto, K.; Sakurai, T.; Hiei, E.; Nishino, Y.; Shinoda, K.; Noguchi, M.; Imai, H.; Irie, M.; Miyashita, M.; Tanaka, N.; Kumagai, K.; Sano, I.; Suematsu, Y.; Okamoto, T.; Miyazaki, H.; Fukushima, H.; Yose, Y.; Zhao, Z. W. Bibcode: 1993RNAOJ...1..375I Altcode: 1993RNOAJ...1..375I The Solar Flare Telescope was built at Mitaka in 1989. This instrument comprises four telescopes which observe (1) Hα images, (2) continuum images, (3) vector magnetic fields, and (4) Doppler velocities, respectively. The instrument aims at the study of energy build-up and energy release in solar flares, in cooperation with the Solar-A satellite (Yohkoh). The Solar Flare Telescope has been in operation since 1990 December. Title: Semi-empirical model of the white light flare on September 19, 1979. Authors: Fang, Cheng; Ding, Mingde; Okamoto, T.; Gan, Weiqun Bibcode: 1993ScChA..36..217F Altcode: The intensities of the continuum emission and the Ca II Ka line of the white light flare on Sep 19, 1979 are measured and analyzed. Their variations with time are given. It is indicated that the continuum emission of this flare appeared in the early impulsive phase and lasted for about 5 - 6 min, with the time of maximum intensity 2 - 3 min earlier than that for the microwave radio burst. Based on the non-LTE theory, a semi-empirical model at a time with the continuum emission being relatively intensive is presented. The results show that the temperature in the flare photosphere is increased by 150 - 250K, and that the continuum emission is produced mainly by the negative hydrogen ion. Title: Ca ii K line asymmetries in two well-observed solar flares of October 18, 1990 Authors: Fang, C.; Hiei, E.; Okamoto, T. Bibcode: 1991SoPh..135...89F Altcode: Two-dimensional evolutions of two flares of October 18, 1990 have been well observed in the CaII K line with a CCD camera at Norikura station of National Astronomical Observatory in Japan. There are two common characteristics for the flares: 3 ∼- 5 min before the impulsive phase, the heating already begins at the footpoints of the flares, but no asymmetry in line emission has been detected. After the onset of the impulsive phase, CaII K line emission at the footpoints shows strong red asymmetry, with the maximum asymmetry occurring at the same time as the peak of the radio bursts. The maximum downward velocity is about 30 ∼ 50 km s−1. For flare 1, blue and red asymmetries were observed in two sides of the footpoint area. They developed and attained a maximum nearly at the same time and the inferred Doppler velocities are comparable (30 ∼ 40 km s−1). This implies that two mass jets started from a small region and ejected along a loop but in opposite directions with roughly equivalent momentum. A possible mechanism has been discussed. Title: Thermal design of a superfluid helium dewar for infrared telescope on-board space flyer unit Authors: Fujii, G.; Hasui, T.; Hama, K.; Okamoto, T.; Machida, T.; Murakami, M.; Matsumoto, T.; Okuda, H.; Kyoya, M. Bibcode: 1988tcls.rept..407F Altcode: The Infrared Telescope in Space (IRTS) onboard Space Flyer Unit is cooled down to 1.8 K by stored superfluid helium, allowing spectroscopic observation even in far infrared regions. The cooled mission life time is longer than several weeks. Minimization of heat leak to the lowest temperature level is one of the primary design goals for the maximum life time. The superfluid helium management at the launching site and also in the zero-g situation should also be well planned. Title: Latitude distribution of the green corona for the period 1951 - 1985. Authors: Okamoto, T. Bibcode: 1986TokRe..20..547O Altcode: No abstract at ADS Title: Facular limb-darkening functions for irradiance modeling. Authors: Hirayama, T.; Okamoto, T.; Hudson, H. S. Bibcode: 1984NASCP2310...59H Altcode: 1984siva.work...59H The limb-darkening function of faculae is an important factor in estimating facular contributions to solar irradiance variations. The authors review the existing photometric data and generate a synthetic limb-darkening function for faculae, which is then compared with the limb-darkening functions currently in use for irradiance modeling. It is found that the excess facular flux ranges from 0.017 to 0.0349 of the solar photospheric flux for the various representations. The present limitation appears to be the lack of comprehensive photometric data. Title: Polarimetry with the coronograph of the Norikura Observatory. II. Authors: Shimizu, I.; Okamoto, T. Bibcode: 1984TokRe..20..240S Altcode: No abstract at ADS Title: Observation of the flare of 12 June 1982 by Norikura coronagraph and Hinotori Authors: Hiei, E.; Okamoto, T.; Tanaka, K. Bibcode: 1983SoPh...86..185H Altcode: Flare activity was observed near the limb with two coronagraphs at the Norikura Solar Observatory and the Soft X-ray Crystal Spectrometer (SOX) aboard HINOTORI. A prominence activation occurred and then Hα brightenings were seen on the disk near the prominence. The prominence became very bright and its electron density increased to 1012.8 cm−3 in 1/2 hour. Loop prominence systems appeared above the Hα brightenings about half an hour after the onset of the flare, and were observed in the coronal lines CaXV 5694Å, FeXIV 5303Å, and FeX 6374Å. Shifted and asymmetric profiles of the emission line of 5303Å were sometimes observed, and turbulent phenomena occurred even in the thermal phase. The energy release site of the flare at the onset would be lower than 20 000 km above the solar limb. Title: Preliminary Observation of Missing Energy Flux of Sunspot Authors: Hirayama, T.; Okamoto, T. Bibcode: 1981SoPh...73...37H Altcode: We have searched for the missing energy flux of the sunspot by measuring white-light photographs over the region around the sunspots exceeding ten times of the diameter of spots. It was found that the excess brightness amounts to 0.3-0.8% of the local continuum intensity immediately beyond the penumbra and smoothly decrease to zero at the edge of our inspected radii of 130 000-160000km. This result suggests that the flux deficit in sunspots of the order of 30% over the umbra-penumbra is roughly the same as the excess flux found in the very large surrounding region which includes photospheric facular contributions. Among nineteen spots fourteen showed this extended bright ring. Narrow band photoelectric scans revealed that the excess radiation originates in the continuum, not from weakened absorption lines. Title: Improvement of a visual photometer for measuring coronal line intensities. Authors: Miyazaki, H.; Okamoto, T.; Fukushima, H. Bibcode: 1981TokRe..19..532M Altcode: No abstract at ADS Title: Helium Abundance from Optical Spectra of Quiescent Prominences. Authors: Hirayama, T.; Nakagomi, Y.; Okamoto, T. Bibcode: 1979phsp.coll...48H Altcode: 1979phsp.conf...48H; 1979IAUCo..44...48H The solar helium abundance is determined from observations of 11 quiescent prominences with a 25-cm coronagraph. The He/H abundance ratio is found to be 16% + or - 4%. This corresponds to a value of 11.2 + or - 0.1 on the logarithmic scale where the hydrogen abundance is set equal to 12. Title: Energy Flows of Extensive Air Showers near Sea Level (Abstract) Authors: Jogo, N.; Kameda, T.; Maeda, T.; Mizushima, K.; Okamoto, T. Bibcode: 1977ICRC....8...24J Altcode: 1977ICRC...15h..24J No abstract at ADS Title: Measurement of photographic density of neutral filters. Authors: Okamoto, T. Bibcode: 1974TokRe..17...40O Altcode: No abstract at ADS Title: A photographic measurement of filter with a densitometer. Authors: Okamoto, T. Bibcode: 1970TokRe..15..188O Altcode: No abstract at ADS