Author name code: magain ADS astronomy entries on 2022-09-14 author:"Magain, Pierre" ------------------------------------------------------------------------ Title: COSMOGRAIL. XIX. Time delays in 18 strongly lensed quasars from 15 years of optical monitoring Authors: Millon, M.; Courbin, F.; Bonvin, V.; Paic, E.; Meylan, G.; Tewes, M.; Sluse, D.; Magain, P.; Chan, J. H. H.; Galan, A.; Joseph, R.; Lemon, C.; Tihhonova, O.; Anderson, R. I.; Marmier, M.; Chazelas, B.; Lendl, M.; Triaud, A. H. M. J.; Wyttenbach, A. Bibcode: 2020A&A...640A.105M Altcode: 2020arXiv200205736M We present the results of 15 years of monitoring lensed quasars, which was conducted by the COSMOGRAIL programme at the Leonhard Euler 1.2 m Swiss Telescope. The decade-long light curves of 23 lensed systems are presented for the first time. We complement our data set with other monitoring data available in the literature to measure the time delays in 18 systems, among which nine reach a relative precision better than 15% for at least one time delay. To achieve this, we developed an automated version of the curve-shifting toolbox PyCS to ensure robust estimation of the time delay in the presence of microlensing, while accounting for the errors due to the imperfect representation of microlensing. We also re-analysed the previously published time delays of RX J1131-1231 and HE 0435-1223, by adding six and two new seasons of monitoring, respectively, and confirming the previous time-delay measurements. When the time delay measurement is possible, we corrected the light curves of the lensed images from their time delay and present the difference curves to highlight the microlensing signal contained in the data. To date, this is the largest sample of decade-long lens monitoring data, which is useful to measure H0 and the size of quasar accretion discs with microlensing as well as to study quasar variability.

All light curves presented in this paper are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/640/A105 Title: VizieR Online Data Catalog: R-band light curves of 23 lensed QSOs (Millon+, 2020) Authors: Millon, M.; Courbin, F.; Bonvin, V.; Paic, E.; Meylan, G.; Tewes, M.; Sluse, D.; Magain, P.; Chan, J. H. H.; Galan, A.; Joseph, R.; Lemon, C.; Tihhonova, O.; Anderson, R. I.; Marmier, M.; Chazelas, B.; Lendl, M.; Triaud, A. H. M. J.; Wyttenbach, A. Bibcode: 2020yCat..36400105M Altcode: R-band cosmograil light curves of lensed quasars taken at the Euler 1.2m Swiss telescope with the EulerCAM and EulerC2 instrument. Additional data taken at the SMARTS 1.3m telescope with the ANDICAM optical/ infrared camera are also included for SDSS J0924+0219 (MacLeod et al., 2015ApJ...806..258M, Cat. J/ApJ/806/258).

For HE 0435-1223 and RX J1131-1231, data taken at the 1.5m telescope at the Maidanak Observatory, the Mercator Belgian telescope and at the SMARTS 1.3 m telescope are included (Courbin et al. 2011A&A...536A..53C, Cat, J/A+A/536/A53, Tewes et al. 2013A&A...553A.120T, 2013A&A...556A..22T, Cat. J/A+A/556/A22). For SDSS J1515+1511, we had the data from Shalyapin & Goicoechea (2017ApJ...836...14S) from the Liverpool Telescope.

(5 data files). Title: COSMOGRAIL. XVII. Time delays for the quadruply imaged quasar PG 1115+080 Authors: Bonvin, V.; Chan, J. H. H.; Millon, M.; Rojas, K.; Courbin, F.; Chen, G. C. -F.; Fassnacht, C. D.; Paic, E.; Tewes, M.; Chao, D. C. -Y.; Chijani, M.; Gilman, D.; Gilmore, K.; Williams, P.; Buckley-Geer, E.; Frieman, J.; Marshall, P. J.; Suyu, S. H.; Treu, T.; Hempel, A.; Kim, S.; Lachaume, R.; Rabus, M.; Anguita, T.; Meylan, G.; Motta, V.; Magain, P. Bibcode: 2018A&A...616A.183B Altcode: 2018arXiv180409183B We present time-delay estimates for the quadruply imaged quasar PG 1115+080. Our results are based on almost daily observations for seven months at the ESO MPIA 2.2 m telescope at La Silla Observatory, reaching a signal-to-noise ratio of about 1000 per quasar image. In addition, we re-analyze existing light curves from the literature that we complete with an additional three seasons of monitoring with the Mercator telescope at La Palma Observatory. When exploring the possible source of bias we considered the so-called microlensing time delay, a potential source of systematic error so far never directly accounted for in previous time-delay publications. In 15 yr of data on PG 1115+080, we find no strong evidence of microlensing time delay. Therefore not accounting for this effect, our time-delay estimates on the individual data sets are in good agreement with each other and with the literature. Combining the data sets, we obtain the most precise time-delay estimates to date on PG 1115+080, with Δt(AB) = 8.3+1.5-1.6 days (18.7% precision), Δt(AC) = 9.9+1.1-1.1 days (11.1%) and Δt(BC) = 18.8+1.6-1.6 days (8.5%). Turning these time delays into cosmological constraints is done in a companion paper that makes use of ground-based Adaptive Optics (AO) with the Keck telescope.

Lightcurve data points are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/616/A183 Title: A cosmology-independent calibration of Type Ia supernovae data Authors: Hauret, C.; Magain, P.; Biernaux, J. Bibcode: 2018MNRAS.479.3996H Altcode: 2018arXiv180610900H; 2018MNRAS.tmp.1635H Recently, the common methodology used to transform Type Ia supernovae (SNe Ia) into genuine standard candles has been suffering criticism. Indeed, it assumes a particular cosmological model [namely the flat Λ cold dark matter (ΛCDM)] to calibrate the standardization corrections parameters, i.e. the dependence of the supernova peak absolute magnitude on its colour, post-maximum decline rate and host galaxy mass. As a result, this assumption could make the data compliant to the assumed cosmology and thus nullify all works previously conducted on model comparison. In this work, we verify the viability of these hypotheses by developing a cosmology-independent approach to standardize SNe Ia data from the recent JLA compilation. Our resulting corrections turn out to be very close to the ΛCDM-based corrections. Therefore, even if a ΛCDM-based calibration is questionable from a theoretical point of view, the potential compliance of SNe Ia data does not happen in practice for the JLA compilation. Previous works of model comparison based on these data do not have to be called into question. However, as this cosmology-independent standardization method has the same degree of complexity than the model-dependent one, it is worth using it in future works, especially if smaller samples are considered, such as the superluminous Type Ic supernovae. Title: VizieR Online Data Catalog: R-band light curves of PG 1115+080 (Bonvin+, 2018) Authors: Bonvin, V.; Chan, J. H. H.; Millon, M.; Rojas, K.; Courbin, F.; Chen, G. C. -F.; Fassnacht, C. D.; Paic, E.; Tewes, M.; Chao, D. C. -Y.; Chijani, M.; Gilman, D.; Gilmore, K.; Williams, P.; Buckley-Geer, E.; Frieman, J.; Marshall, P. J.; Suyu, S. H.; Treu, T.; Hempel, A.; Kim, S.; Lachaume, R.; Rabus, M.; Anguita, T.; Meylan, G.; Motta, V.; Magain, P. Bibcode: 2018yCat..36160183B Altcode: We have been monitoring the quadruply lensed quasar PG1115+080 for 8 months in the R band (~600-720nm) using the MPIA/ESO 2.2m telescope. The resulting R-band light curves of the quadruply lensed quasar PG1115+080, is displayed in Fig. 2 of the paper.

(1 data file). Title: High-precision multiwavelength eclipse photometry of the ultra-hot gas giant exoplanet WASP-103 b Authors: Delrez, L.; Madhusudhan, N.; Lendl, M.; Gillon, M.; Anderson, D. R.; Neveu-VanMalle, M.; Bouchy, F.; Burdanov, A.; Collier-Cameron, A.; Demory, B. -O.; Hellier, C.; Jehin, E.; Magain, P.; Maxted, P. F. L.; Queloz, D.; Smalley, B.; Triaud, A. H. M. J. Bibcode: 2018MNRAS.474.2334D Altcode: 2017arXiv171102566D We present 16 occultation and three transit light curves for the ultra-short period hot Jupiter WASP-103b, in addition to five new radial velocity measurements. We combine these observations with archival data and perform a global analysis of the resulting extensive data set, accounting for the contamination from a nearby star. We detect the thermal emission of the planet in both the z΄ and KS bands, the measured occultation depths being 699±110 ppm (6.4σ) and 3567_{-350}^{+400} ppm (10.2σ), respectively. We use these two measurements, together with recently published HST/WFC3 data, to derive joint constraints on the properties of WASP-103b's dayside atmosphere. On one hand, we find that the z΄ band and WFC3 data are best fit by an isothermal atmosphere at 2900 K or an atmosphere with a low H2O abundance. On the other hand, we find an unexpected excess in the KS band measured flux compared to these models, which requires confirmation with additional observations before any interpretation can be given. From our global data analysis, we also derive a broad-band optical transmission spectrum that shows a minimum around 700 nm and increasing values towards both shorter and longer wavelengths. This is in agreement with a previous study based on a large fraction of the archival transit light curves used in our analysis. The unusual profile of this transmission spectrum is poorly matched by theoretical spectra and is not confirmed by more recent observations at higher spectral resolution. Additional data, in both emission and transmission, are required to better constrain the atmospheric properties of WASP-103b. Title: Analysis of luminosity distributions of strong lensing galaxies: subtraction of diffuse lensed signal Authors: Biernaux, J.; Magain, P.; Hauret, C. Bibcode: 2017A&A...604A..46B Altcode: 2017arXiv170502282B Context. Strong gravitational lensing gives access to the total mass distribution of galaxies. It can unveil a great deal of information about the lenses' dark matter content when combined with the study of the lenses' light profile. However, gravitational lensing galaxies, by definition, appear surrounded by lensed signal, both point-like and diffuse, that is irrelevant to the lens flux. Therefore, the observer is most often restricted to studying the innermost portions of the galaxy, where classical fitting methods show some instabilities.
Aims: We aim at subtracting that lensed signal and at characterising some lenses' light profile by computing their shape parameters (half-light radius, ellipticity, and position angle). Our objective is to evaluate the total integrated flux in an aperture the size of the Einstein ring in order to obtain a robust estimate of the quantity of ordinary (luminous) matter in each system.
Methods: We are expanding the work we started in a previous paper that consisted in subtracting point-like lensed images and in independently measuring each shape parameter. We improve it by designing a subtraction of the diffuse lensed signal, based only on one simple hypothesis of symmetry. We apply it to the cases where it proves to be necessary. This extra step improves our study of the shape parameters and we refine it even more by upgrading our half-light radius measurement method. We also calculate the impact of our specific image processing on the error bars.
Results: The diffuse lensed signal subtraction makes it possible to study a larger portion of relevant galactic flux, as the radius of the fitting region increases by on average 17%. We retrieve new half-light radii values that are on average 11% smaller than in our previous work, although the uncertainties overlap in most cases. This shows that not taking the diffuse lensed signal into account may lead to a significant overestimate of the half-light radius. We are also able to measure the flux within the Einstein radius and to compute secure error bars to all of our results. Title: Cosmological Time, Entropy and Infinity Authors: Hauret, Clémentine; Magain, Pierre; Biernaux, Judith Bibcode: 2017Entrp..19..357H Altcode: Time is a parameter playing a central role in our most fundamental modelling of natural laws. Relativity theory shows that the comparison of times measured by different clocks depends on their relative motion and on the strength of the gravitational field in which they are embedded. In standard cosmology, the time parameter is the one measured by fundamental clocks (i.e., clocks at rest with respect to the expanding space). This proper time is assumed to flow at a constant rate throughout the whole history of the universe. We make the alternative hypothesis that the rate at which the cosmological time flows depends on the dynamical state of the universe. In thermodynamics, the arrow of time is strongly related to the second law, which states that the entropy of an isolated system will always increase with time or, at best, stay constant. Hence, we assume that the time measured by fundamental clocks is proportional to the entropy of the region of the universe that is causally connected to them. Under that simple assumption, we find it possible to build toy cosmological models that present an acceleration of their expansion without any need for dark energy while being spatially closed and finite, avoiding the need to deal with infinite values. Title: A seven-planet resonant chain in TRAPPIST-1 Authors: Luger, Rodrigo; Sestovic, Marko; Kruse, Ethan; Grimm, Simon L.; Demory, Brice-Olivier; Agol, Eric; Bolmont, Emeline; Fabrycky, Daniel; Fernandes, Catarina S.; Van Grootel, Valérie; Burgasser, Adam; Gillon, Michaël; Ingalls, James G.; Jehin, Emmanuël; Raymond, Sean N.; Selsis, Franck; Triaud, Amaury H. M. J.; Barclay, Thomas; Barentsen, Geert; Howell, Steve B.; Delrez, Laetitia; de Wit, Julien; Foreman-Mackey, Daniel; Holdsworth, Daniel L.; Leconte, Jérémy; Lederer, Susan; Turbet, Martin; Almleaky, Yaseen; Benkhaldoun, Zouhair; Magain, Pierre; Morris, Brett M.; Heng, Kevin; Queloz, Didier Bibcode: 2017NatAs...1E.129L Altcode: 2017NatAs...1..129L; 2017arXiv170304166L The TRAPPIST-1 system is the first transiting planet system found orbiting an ultracool dwarf star 1 . At least seven planets similar in radius to Earth were previously found to transit this host star 2 . Subsequently, TRAPPIST-1 was observed as part of the K2 mission and, with these new data, we report the measurement of an 18.77 day orbital period for the outermost transiting planet, TRAPPIST-1 h, which was previously unconstrained. This value matches our theoretical expectations based on Laplace relations 3 and places TRAPPIST-1 h as the seventh member of a complex chain, with three-body resonances linking every member. We find that TRAPPIST-1 h has a radius of 0.752 R ⊕ and an equilibrium temperature of 173 K. We have also measured the rotational period of the star to be 3.3 days and detected a number of flares consistent with a low-activity, middle-aged, late M dwarf. Title: Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1 Authors: Gillon, Michaël; Triaud, Amaury H. M. J.; Demory, Brice-Olivier; Jehin, Emmanuël; Agol, Eric; Deck, Katherine M.; Lederer, Susan M.; de Wit, Julien; Burdanov, Artem; Ingalls, James G.; Bolmont, Emeline; Leconte, Jeremy; Raymond, Sean N.; Selsis, Franck; Turbet, Martin; Barkaoui, Khalid; Burgasser, Adam; Burleigh, Matthew R.; Carey, Sean J.; Chaushev, Aleksander; Copperwheat, Chris M.; Delrez, Laetitia; Fernandes, Catarina S.; Holdsworth, Daniel L.; Kotze, Enrico J.; Van Grootel, Valérie; Almleaky, Yaseen; Benkhaldoun, Zouhair; Magain, Pierre; Queloz, Didier Bibcode: 2017Natur.542..456G Altcode: 2017arXiv170301424G One aim of modern astronomy is to detect temperate, Earth-like exoplanets that are well suited for atmospheric characterization. Recently, three Earth-sized planets were detected that transit (that is, pass in front of) a star with a mass just eight per cent that of the Sun, located 12 parsecs away. The transiting configuration of these planets, combined with the Jupiter-like size of their host star—named TRAPPIST-1—makes possible in-depth studies of their atmospheric properties with present-day and future astronomical facilities. Here we report the results of a photometric monitoring campaign of that star from the ground and space. Our observations reveal that at least seven planets with sizes and masses similar to those of Earth revolve around TRAPPIST-1. The six inner planets form a near-resonant chain, such that their orbital periods (1.51, 2.42, 4.04, 6.06, 9.1 and 12.35 days) are near-ratios of small integers. This architecture suggests that the planets formed farther from the star and migrated inwards. Moreover, the seven planets have equilibrium temperatures low enough to make possible the presence of liquid water on their surfaces. Title: Red worlds: Spitzer exploration of a compact system of temperate terrestrial planets transiting a nearby Jupiter-sized star Authors: Gillon, Michael; Burdanov, Artem; Delrez, Laetitia; Jehin, Emmanuel; Magain, Pierre; Van Grootel, Valerie; Bolmont, Emeline; Leconte, Jeremy; Raymond, Sean; Selsis, Franck; Demory, Brice-Olivier; Queloz, Didier; Triaud, Amaury; de Wit, Julien; Burgasser, Adam; Carey, Sean; Ingalls, Jim; Lederer, Sue; Agol, Eric; Deck, Katherine Bibcode: 2016sptz.prop13067G Altcode: The recently detected TRAPPIST-1 planetary system represents a unique opportunity to extend the nascent field of comparative exoplanetology into the realm of temperate terrestrial worlds. It is composed of at least three Earth-sized planets similar in sizes and irradiations to Earth and Venus transiting an ultra-cool dwarf star only 39 light-years away. Thanks to the Jupiter-size and infrared brightness of their host star, the planets are amenable for detailed atmospheric characterization with JWST, including for biosignatures detection. Our Spitzer Exploration Science Program aims to prepare and optimize the detailed study of this fascinating planetary system through the two following complementary sub-programs: (1) a 480 hrs continuous monitoring of the star to explore its full inner system up to its ice line in a search for any other transiting object(s) (planet, moon, Trojan) with a sensitivity high enough to detect any body as small as Ganymede, and (2) the observation of ~130 transits of the planets (520 hrs). This second part has two goals. First, to measure precisely the planets' masses and eccentricities through the Transit Timing Variations method, to constrain strongly their compositions and energy budgets. Secondly, to measure with an extremely high precision the planets' effective radii at 4.5 microns to assess, when combined with future HST/WFC3 observations, the presence of an atmosphere around them. The two complementary parts of this program will make it a long-lasting legacy of Spitzer to the fields of comparative exoplanetology and astrobiology, by providing the necessary measurements on the inner system of TRAPPIST-1 (complete census, masses, eccentricities, first insights on atmospheres) required to initiate and optimize the detailed atmospheric characterization of its different components with JWST and other future facilities.

Data from program 13175 can also be found in this program. Title: Variable time flow as an alternative to dark energy Authors: Magain, Pierre; Hauret, Clémentine Bibcode: 2016arXiv160606169M Altcode: Time is a parameter playing a central role in our most fundamental modelling of natural laws. Relativity theory shows that the comparison of times measured by different clocks depends on their relative motions and on the strength of the gravitational field in which they are embedded. In standard cosmology, the time parameter is the one measured by fundamental clocks, i.e. clocks at rest with respect to the expanding space. This proper time is assumed to flow at a constant rate throughout the whole history of the Universe. We make the alternative hypothesis that the rate at which cosmological time flows depends on the global geometric curvature the Universe. Using a simple one-parameter model for the relation between proper time and curvature, we build a cosmological model that fits the Type Ia Supernovae data (the best cosmological standard candles) without the need for dark energy nor probably exotic dark matter. Title: Temperate Earth-sized planets transiting a nearby ultracool dwarf star Authors: Gillon, Michaël; Jehin, Emmanuël; Lederer, Susan M.; Delrez, Laetitia; de Wit, Julien; Burdanov, Artem; Van Grootel, Valérie; Burgasser, Adam J.; Triaud, Amaury H. M. J.; Opitom, Cyrielle; Demory, Brice-Olivier; Sahu, Devendra K.; Bardalez Gagliuffi, Daniella; Magain, Pierre; Queloz, Didier Bibcode: 2016Natur.533..221G Altcode: 2016arXiv160507211G Star-like objects with effective temperatures of less than 2,700 kelvin are referred to as ‘ultracool dwarfs’. This heterogeneous group includes stars of extremely low mass as well as brown dwarfs (substellar objects not massive enough to sustain hydrogen fusion), and represents about 15 per cent of the population of astronomical objects near the Sun. Core-accretion theory predicts that, given the small masses of these ultracool dwarfs, and the small sizes of their protoplanetary disks, there should be a large but hitherto undetected population of terrestrial planets orbiting them—ranging from metal-rich Mercury-sized planets to more hospitable volatile-rich Earth-sized planets. Here we report observations of three short-period Earth-sized planets transiting an ultracool dwarf star only 12 parsecs away. The inner two planets receive four times and two times the irradiation of Earth, respectively, placing them close to the inner edge of the habitable zone of the star. Our data suggest that 11 orbits remain possible for the third planet, the most likely resulting in irradiation significantly less than that received by Earth. The infrared brightness of the host star, combined with its Jupiter-like size, offers the possibility of thoroughly characterizing the components of this nearby planetary system. Title: Long-term activity and outburst of comet C/2013 A1 (Siding Spring) from narrow-band photometry and long-slit spectroscopy Authors: Opitom, C.; Guilbert-Lepoutre, A.; Jehin, E.; Manfroid, J.; Hutsemékers, D.; Gillon, M.; Magain, P.; Roberts-Borsani, G.; Witasse, O. Bibcode: 2016A&A...589A...8O Altcode: 2015arXiv151007514O We present a unique data set of more than one year's worth of regular observations of comet C/2013 A1(Siding Spring) taken with TRAPPIST, along with low-resolution spectra obtained with the ESO/VLT FORS 2 instrument. The comet made a close approach to Mars on October 19, 2014, and was then observed by many space-borne and ground-based telescopes. We followed the evolution of the OH, NH, CN, C3, and C2 production rates as well as the Afρ parameter, a proxy for the dust production. We detected an outburst two weeks after perihelion, with gas and dust production rates increased by a factor of five within a few days. By modelling the shape of the CN and C2 radial profiles, we determined that the outburst happened on November 10 around 15:30 UT (±5 h) and measured a gas expansion velocity of 1.1 ± 0.2 km s-1. We used a thermal evolution model to reproduce the activity pattern and outburst. Our results are consistent with the progressive formation of a dust mantle explaining the shallow dependence of gas production rates, which may be partially blown off during the outburst. We studied the evolution of gas composition, using various ratios such as CN/OH, C2/OH, or C3/OH, which showed little or no variation with heliocentric distance, including at the time of the outburst. This indicates a relative level of homogeneity of the nucleus composition.

Based on observations obtained at the ESO/VLT in the framework of program 93.C-0619. Title: Two Birds One Stone: Simultaneous Atmospheric Pre-Screening of Two Temperate Earth-Sized Exoplanets During Their Double Transit Authors: de Wit, Julien; Burdanov, Artem; Burgasser, Adam J.; Delrez, Laetitia; Demory, Brice-Olivier; Gillon, Michael; Jehin, Emmanuel; Lederer, Susan; Lewis, Nikole; Magain, Pierre; Queloz, Didier; Triaud, Amaury; Van Grootel, Valerie Bibcode: 2016hst..prop14500D Altcode: We have detected three temperate Earth-sized planets transiting an ultra-cool dwarf star only 12 pc away, TRAPPIST-1. This discovery sparks the era of detailed characterization and habitability assessment of Earth-sized exoplanets. It also opens a new chapter for exoplanetology: comparative planetology in the realm of temperate terrestrial planets.

TRAPPIST-1's system is currently the subject of an intense, worldwide follow-up effort that spans the electromagnetic spectrum from the UV to radio. Being uniquely suited for NIR and UV high-precision observations, HST has a key role to play in this follow-up effort.

Updated ephemerids resulting from two Spitzer DDTs show that TRAPPIST-1 b and c will transit simultaneously on May 4th, 2016 at 9h10 UT providing a unique and rare opportunity to study for the first time, and simultaneously, the atmospheres of temperate Earth-sized planets outside of the Solar System. We propose a 4-orbit pre-screening program with WFC3 to definitely test the H/He-dominated atmospheric scenario for these planets and determine the relative inclination of both planets, bringing invaluable constraints on the dynamical history of the system. Title: On the eclipsing binary nature of a nearby ultracool dwarf Authors: Gillon, Michael; Jehin, Emmanuel; de Wit, Julien; Demory, Brice-Olivier; Burgasser, Adam; Van Grootel, Valerie; Lederer, Susan; Triaud, Amaury; Delrez, Laetitia; Burdanov, Artem; Queloz, Didier; Magain, Pierre Bibcode: 2016sptz.prop12130G Altcode: The eclipsing binary nature of a nearby ultracool dwarf has just been revealed. The aim of this DDT is to investigate this nearby system further through high-precision infrared time-series photometry. Title: On the eclipsing binary nature of a nearby ultracool dwarf Authors: Gillon, Michael; de Wit, Julien; Jehin, Emmanuel; Burdanov, Artem; Van Grootel, valerie. vangrootel@ulg. ac. be; Delrez, Laetitia; Magain, Pierre; Burgasser, Adam; Demory, Brice-Olivier; Triaud, Amaury; Queloz, Didier; Lederer, Sue Bibcode: 2016sptz.prop12126G Altcode: The eclipsing binary nature of a nearby ultracool dwarf has just been revealed. The aim of this DDT is to investigate this nearby system further through high-precision infrared time-series photometry. Title: Analysis of luminosity distributions and the shape parameters of strong gravitational lensing elliptical galaxies Authors: Biernaux, J.; Magain, P.; Sluse, D.; Chantry, V. Bibcode: 2016A&A...585A..84B Altcode: 2015arXiv151009118B Context. The luminosity profiles of galaxies acting as strong gravitational lenses can be tricky to study. Indeed, strong gravitational lensing images display several lensed components, both point-like and diffuse, around the lensing galaxy. Those objects limit the study of the galaxy luminosity to its inner parts. Therefore, the usual fitting methods perform rather badly on such images. Previous studies of strong lenses luminosity profiles using software such as GALFIT or IMFITFITS and various PSF-determining methods have resulted in somewhat discrepant results.
Aims: The present work aims at investigating the causes of those discrepancies, as well as at designing more robust techniques for studying the morphology of early-type lensing galaxies with the ability to subtract a lensed signal from their luminosity profiles.
Methods: We design a new method to independently measure each shape parameter, namely, the position angle, ellipticity, and half-light radius of the galaxy. Our half-light radius measurement method is based on an innovative scheme for computing isophotes that is well suited to measuring the morphological properties of gravititational lensing galaxies. Its robustness regarding various specific aspects of gravitational lensing image processing is analysed and tested against GALFIT. It is then applied to a sample of systems from the CASTLES database.
Results: Simulations show that, when restricted to small, inner parts of the lensing galaxy, the technique presented here is more trustworthy than GALFIT. It gives more robust results than GALFIT, which shows instabilities regarding the fitting region, the value of the Sérsic index, and the signal-to-noise ratio. It is therefore better suited than GALFIT for gravitational lensing galaxies. It is also able to study lensing galaxies that are not much larger than the PSF. New values for the half-light radius of the objects in our sample are presented and compared to previous works.

Table 6 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/585/A84 Title: TRAPPIST photometry and imaging monitoring of comet C/2013 R1 (Lovejoy): Implications for the origin of daughter species Authors: Opitom, C.; Jehin, E.; Manfroid, J.; Hutsemékers, D.; Gillon, M.; Magain, P. Bibcode: 2015A&A...584A.121O Altcode: 2015arXiv150701520O We report the results of the narrow-band photometry and imaging monitoring of comet C/2013 R1 (Lovejoy) with the robotic telescope TRAPPIST (La Silla observatory). We gathered around 400 images over 8 months pre- and post-perihelion between September 12, 2013 and July 6, 2014. We followed the evolution of the OH, NH, CN, C3, and C2 production rates computed with the Haser model, as well as the evolution of the dust production. All five gas species display an asymmetry about perihelion, since the rate of brightening is steeper than the rate of fading. The study of the coma morphology reveals gas and dust jets that indicate one or several active zone(s) on the nucleus. The dust, C2, and C3 morphologies present some similarities, while the CN morphology is different. OH and NH are enhanced in the tail direction. The study of the evolution of the comet activity shows that the OH, NH, and C2 production rate evolution with the heliocentric distance is correlated to the dust evolution. The CN and, to a lesser extent, the C3 do not display such a correlation with the dust. This evidence and the comparison with parent species production rates indicate that C2 and C3, on one hand, and OH and NH, on the other, could be - at least partially - released from organic - rich grains and icy grains. On the contrary, all evidences point to HCN being the main parent of CN in this comet.

Appendix A is available in electronic form at http://www.aanda.org Title: Five years of comet narrow band photometry and imaging with TRAPPIST Authors: Opitom, Cyrielle; Jehin, Emmanuel; Manfroid, Jean; Hutsemékers, Damien; Gillon, Michaël; Magain, Pierre Bibcode: 2015DPS....4750602O Altcode: TRAPPIST is a 60-cm robotic telescope in La Silla Observatory [1] mainly dedicated to the study of exoplanets and comets. The telescope is equipped with a set of narrow band cometary filters designed by the NASA for the Hale-Bopp observing campaign [2]. Since its installation in 2010, we gathered a high quality and homogeneous data set of more than 30 bright comets observed with narrow band filters. Some comets were only observed for a few days but others have been observed weekly during several months on both sides of perihelion. From the images, we derived OH, NH, CN, C2, and C3 production rates using a Haser [3] model in addition to the Afρ parameter as a proxy for the dust production. We computed production rates ratios and the dust color for each comet to study their composition and followed the evolution of these ratios and colors with the heliocentric distance.The TRAPPIST data set, rich of more than 10000 images obtained and reduced in an homogeneous way, allows us to address several fundamental questions such as the pristine or evolutionary origin of composition differences among comets. The evolution of comet activity with the heliocentric distance, the differences between species, and from comet to comet, will be discussed. Finally, the first results about the one year campaign on comet C/2013 US10 (Catalina) and our recent work on the re-determination of Haser scalelengths will be presented.[1] Jehin et al., The Messenger, 145, 2-6, 2011[2] Farnham et al., Icarus, 147, 180-204, 2000[3] Haser, Bulletin de l’Académie Royal des Sciences de Belgique,63, 739, 1957 Title: VizieR Online Data Catalog: Shape parameters of lensing galaxies (Biernaux+, 2016) Authors: Biernaux, J.; Magain, P.; Sluse, D.; Chantry, V. Bibcode: 2015yCat..35850084B Altcode: In the paper we explain procedures designed to measure the position angle, the ellipticity and the half-light radius of lensing galaxies, that rely on an innovative scheme to compute isophotes. Table 6 details frame per frame the characteristics of the masks used in this work. Those values are in fact the shape parameters of the galaxies, before correcting from the effect of the PSF. The relative coordinates of the galaxy center, with regards to a reference lensed image, and the size of the region of interest are given as well. The reference lensed image can be found in Fig. 2 in the paper and is the one labelled A (or A1 in some cases).

(2 data files). Title: On the nature of cosmological time Authors: Magain, Pierre; Hauret, Clémentine Bibcode: 2015arXiv150502052M Altcode: Time is a parameter playing a central role in our most fundamental modeling of natural laws. Relativity theory shows that the comparison of times measured by different clocks depends on their relative motions and on the strength of the gravitational field in which they are embedded. In standard cosmology, the time parameter is the one measured by fundamental clocks, i.e. clocks at rest with respect to the expanding space. This proper time is assumed to flow at a constant rate throughout the whole history of the Universe. We make the alternative hypothesis that the rate at which cosmological time flows depends on the dynamical state of the Universe. In thermodynamics, the arrow of time is strongly related to the second law, which states that the entropy of an isolated system will always increase with time or, at best, stay constant. Hence, we assume that time measured by fundamental clocks is proportional to the entropy of the region of the Universe that is causally connected to them. Under that simple assumption, we build a cosmological model that explains the Type Ia Supernovae data (the best cosmological standard candles) without the need for exotic dark matter nor dark energy. Title: TRAPPIST monitoring of comet C/2012 F6 (Lemmon) Authors: Opitom, C.; Jehin, E.; Manfroid, J.; Hutsemékers, D.; Gillon, M.; Magain, P. Bibcode: 2015A&A...574A..38O Altcode: We report the results of the long-term narrowband photometry and imaging monitoring of comet C/2012 F6 (Lemmon) with the robotic TRAPPIST telescope (La Silla Observatory). Observations covered 52 nights pre- and post-perihelion between December 11, 2012, and June 11, 2013 (perihelion: 24 March, 2013). We followed the evolution of the OH, NH, CN, C3, and C2 production rates computed with the Haser model as well as the evolution of the A(θ)fρ parameter as a proxy for the dust production. All five gas species display similar slopes for the heliocentric dependence. An asymmetry about perihelion is observed, the rate of brightening being steeper than the rate of fading. The chemical composition of the comet's coma changes slightly along the orbit: the relative abundance of C2 to CN increases with the heliocentric distance (r) below -1.4 au and decreases with r beyond 1.4 au while the C3-to-CN ratio is constant during our observations. The behavior of the dust is different from that of the gas, the slope of the heliocentric dependence becoming steeper in early February, correlated to a change in the visual lightcurve slope. However, the dust color does not vary during the observations. The application of several enhancement techniques on the images revealed structures in the CN, C3, and C2 images. These features imply the existence of one or several active zone(s) on the comet nucleus. The shape of the structures is similar in these three filters and changes from a roughly hourglass shape in December and January to a corkscrew shape in February and March. The structures in the continuum filters (sampling the dust) are not correlated to those observed for the gas. During several full nights in February, we observed changes in the CN and C2 structures that repeated periodically because of the nucleus rotation, our derived rotational period being of 9.52 ± 0.05 h.

Full Tables 2, 4, 6 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/574/A38 Title: A global analysis of Spitzer and new HARPS data confirms the loneliness and metal-richness of GJ 436 b Authors: Lanotte, A. A.; Gillon, M.; Demory, B. -O.; Fortney, J. J.; Astudillo, N.; Bonfils, X.; Magain, P.; Delfosse, X.; Forveille, T.; Lovis, C.; Mayor, M.; Neves, V.; Pepe, F.; Queloz, D.; Santos, N.; Udry, S. Bibcode: 2014A&A...572A..73L Altcode: 2014arXiv1409.4038L Context. GJ 436b is one of the few transiting warm Neptunes for which a detailed characterisation of the atmosphere is possible, whereas its non-negligible orbital eccentricity calls for further investigation. Independent analyses of several individual datasets obtained with Spitzer have led to contradicting results attributed to the different techniques used to treat the instrumental effects.
Aims: We aim at investigating these previous controversial results and developing our knowledge of the system based on the full Spitzer photometry dataset combined with new Doppler measurements obtained with the HARPS spectrograph. We also want to search for additional planets.
Methods: We optimise aperture photometry techniques and the photometric deconvolution algorithm DECPHOT to improve the data reduction of the Spitzer photometry spanning wavelengths from 3-24 μm. Adding the high-precision HARPS radial velocity data, we undertake a Bayesian global analysis of the system considering both instrumental and stellar effects on the flux variation.
Results: We present a refined radius estimate of RP = 4.10 ± 0.16 R⊕ , mass MP = 25.4 ± 2.1 M⊕, and eccentricity e = 0.162 ± 0.004 for GJ 436b. Our measured transit depths remain constant in time and wavelength, in disagreement with the results of previous studies. In addition, we find that the post-occultation flare-like structure at 3.6 μm that led to divergent results on the occultation depth measurement is spurious. We obtain occultation depths at 3.6, 5.8, and 8.0 μm that are shallower than in previous works, in particular at 3.6 μm. However, these depths still appear consistent with a metal-rich atmosphere depleted in methane and enhanced in CO/CO2, although perhaps less than previously thought. We could not detect a significant orbital modulation in the 8 μm phase curve. We find no evidence of a potential planetary companion, stellar activity, or a stellar spin-orbit misalignment.
Conclusions: Recent theoretical models invoking high-metallicity atmospheres for warm Neptunes are a reasonable match to our results, but we encourage new modelling efforts based on our revised data. Future observations covering a wide wavelength range of GJ 436b and other Neptune-class exoplanets will further illuminate their atmosphere properties, whilst future accurate radial velocity measurements might explain the eccentricity.

Based on observations made with the HARPS spectrograph on the 3.6 m ESO telescope at the ESO La Silla Observatory, Chile.Table 2 and Figs. 5-7 are available in electronic form at http://www.aanda.org Title: VizieR Online Data Catalog: TRAPPIST monitoring of comet C/2012 F6 (Lemmon) (Opitom+, 2015) Authors: Opitom, C.; Jehin, E.; Manfroid, J.; Hutsemekers, D.; Gillon, M.; Magain, P. Bibcode: 2014yCat..35740038O Altcode: 2014yCat..35749038O Observational circumstances, OH, NH, CN, C3 and C2 production and A(θ)f{rho} values of comet C/2012 F6 (Lemmon) obtained using the TRAPPIST telescope

(3 data files). Title: Search for a habitable terrestrial planet transiting the nearby red dwarf GJ 1214 Authors: Gillon, M.; Demory, B. -O.; Madhusudhan, N.; Deming, D.; Seager, S.; Zsom, A.; Knutson, H. A.; Lanotte, A. A.; Bonfils, X.; Désert, J. -M.; Delrez, L.; Jehin, E.; Fraine, J. D.; Magain, P.; Triaud, A. H. M. J. Bibcode: 2014A&A...563A..21G Altcode: 2013arXiv1307.6722G High-precision eclipse spectrophotometry of transiting terrestrial exoplanets represents a promising path for the first atmospheric characterizations of habitable worlds and the search for life outside our solar system. The detection of terrestrial planets transiting nearby late-type M-dwarfs could make this approach applicable within the next decade, with soon-to-come general facilities. In this context, we previously identified GJ 1214 as a high-priority target for a transit search, as the transit probability of a habitable planet orbiting this nearby M4.5 dwarf would be significantly enhanced by the transiting nature of GJ 1214 b, the super-Earth already known to orbit the star. Based on this observation, we have set up an ambitious high-precision photometric monitoring of GJ 1214 with the Spitzer Space Telescope to probe the inner part of its habitable zone in search of a transiting planet as small as Mars. We present here the results of this transit search. Unfortunately, we did not detect any other transiting planets. Assuming that GJ 1214 hosts a habitable planet larger than Mars that has an orbital period smaller than 20.9 days, our global analysis of the whole Spitzer dataset leads to an a posteriori no-transit probability of ~98%. Our analysis allows us to significantly improve the characterization of GJ 1214 b, to measure its occultation depth to be 70 ± 35 ppm at 4.5 μm, and to constrain it to be smaller than 205 ppm (3σ upper limit) at 3.6 μm. In agreement with the many transmission measurements published so far for GJ 1214 b, these emission measurements are consistent with both a metal-rich and a cloudy hydrogen-rich atmosphere.

The photometric time series used in this work are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/563/A21 Title: VizieR Online Data Catalog: GJ 1214 Trappist and Spitzer light curves (Gillon+, 2014) Authors: Gillon, M.; Deming, D.; Madhusudhan, N.; Deming, D.; Seager, S.; Zsom, A.; Knutson, H. A.; Lanotte, A. A.; Bonfils, X.; Desert, J. -M.; Delrez, L.; Jehin, E.; Fraine, J. D.; Magain, P.; Triaud, A. H. M. J. Bibcode: 2014yCat..35630021G Altcode: 2014yCat..35639021G Files trappist.dat, spitzer1.dat, and spitzer2.dat contain the photometric time-series presented in the paper and obtained by the TRAPPIST and Spitzer telescopes.

(3 data files). Title: TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) Authors: Jehin, E.; Gillon, M.; Opitom, C.; Manfroid, J.; Hutsemékers, D.; Magain, P. Bibcode: 2013EPSC....8..968J Altcode: TRAPPIST is a 60-cm robotic telescope that has been installed in June 2010 at the ESO La Silla Observatory [1]. Operated from Liège (Belgium) it is devoted to the detection and characterisation of exoplanets and to the study of comets and other small bodies in the Solar System. We describe here the hardware and the goals of the project and give an overview of the comet production rates monitoring after three years of operations. Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses. XIV. Time delay of the doubly lensed quasar SDSS J1001+5027 Authors: Rathna Kumar, S.; Tewes, M.; Stalin, C. S.; Courbin, F.; Asfandiyarov, I.; Meylan, G.; Eulaers, E.; Prabhu, T. P.; Magain, P.; Van Winckel, H.; Ehgamberdiev, Sh. Bibcode: 2013A&A...557A..44R Altcode: 2013arXiv1306.5105R This paper presents optical R-band light curves and the time delay of the doubly imaged gravitationally lensed quasar SDSS J1001+5027 at a redshift of 1.838. We have observed this target for more than six years, between March 2005 and July 2011, using the 1.2-m Mercator Telescope, the 1.5-m telescope of the Maidanak Observatory, and the 2-m Himalayan Chandra Telescope. Our resulting light curves are composed of 443 independent epochs, and show strong intrinsic quasar variability, with an amplitude of the order of 0.2 magnitudes. From this data, we measure the time delay using five different methods, all relying on distinct approaches. One of these techniques is a new development presented in this paper. All our time-delay measurements are perfectly compatible. By combining them, we conclude that image A is leading B by 119.3 ± 3.3 days (1σ, 2.8% uncertainty), including systematic errors. It has been shown recently that such accurate time-delay measurements offer a highly complementary probe of dark energy and spatial curvature, as they independently constrain the Hubble constant. The next mandatory step towards using SDSS J1001+5027 in this context will be the measurement of the velocity dispersion of the lensing galaxy, in combination with deep Hubble Space Telescope imaging.

Based on observations made with the 2.0-m Himalayan Chandra Telescope (Hanle, India), the 1.5-m AZT-22 telescope (Maidanak Observatory, Uzbekistan), and the 1.2-m Mercator Telescope. Mercator is operated on the island of La Palma by the Flemish Community, at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.Light curves are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/557/A44 Title: TRAPPIST monitoring of comet C/2012 F6 (Lemmon) Authors: Opitom, C.; Jehin, E.; Manfroid, J.; Hutsemékers, D.; Gillon, M.; Magain, P. Bibcode: 2013EPSC....8..764O Altcode: Comet C/2012 F6 is a long-period comet that reached perihelion on March 23, 2012. The unexpected brightness of this comet since December 2012 allowed us to obtain narrowband photometry and to study its chemical composition as well as its rotation. Title: Herschel imaging and spectroscopy of the nebula around the luminous blue variable star WRAY 15-751 Authors: Vamvatira-Nakou, C.; Hutsemékers, D.; Royer, P.; Nazé, Y.; Magain, P.; Exter, K.; Waelkens, C.; Groenewegen, M. A. T. Bibcode: 2013A&A...557A..20V Altcode: 2013arXiv1307.0759V We have obtained far-infrared Herschel-PACS imaging and spectroscopic observations of the nebular environment of the luminous blue variable (LBV) WRAY 15-751. The far-infrared images clearly show that the main, dusty nebula is a shell of radius 0.5 pc and width 0.35 pc extending outside the Hα nebula. Furthermore, these images reveal a second, bigger and fainter dust nebula that is observed for the first time. Both nebulae lie in an empty cavity, very likely the remnant of the O-star wind bubble formed when the star was on the main sequence. The kinematic ages of the nebulae are calculated to be about 2 × 104 and 8 × 104 years, and we estimated that each nebula contains ~0.05 M⊙ of dust. Modeling of the inner nebula indicates a Fe-rich dust. The far-infrared spectrum of the main nebula revealed forbidden emission lines coming from ionized and neutral gas. Our study shows that the main nebula consists of a shell of ionized gas surrounded by a thin photodissociation region illuminated by an "average" early-B star. We derive the abundance ratios N/O = 1.0 ± 0.4 and C/O = 0.4 ± 0.2, which indicate a mild N/O enrichment. From both the ionized and neutral gas components we estimate that the inner shell contains 1.7 ± 0.6 M⊙ of gas. Assuming a similar dust-to-gas ratio for the outer nebula, the total mass ejected by WRAY 15-751 amounts to 4 ± 2 M⊙. The measured abundances, masses and kinematic ages of the nebulae were used to constrain the evolution of the star and the epoch at which the nebulae were ejected. Our results point to an ejection of the nebulae during the red super-giant (RSG) evolutionary phase of an ~40 M⊙ star. The multiple shells around the star suggest that the mass-loss was not a continuous ejection but rather a series of episodes of extreme mass-loss. Our measurements are compatible with the recent evolutionary tracks computed for an ~40 M⊙ star with little rotation. They support the O-BSG-RSG-YSG-LBV filiation and the idea that high-luminosity and low-luminosity LBVs follow different evolutionary paths.

Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Based in part on observations collected at the European Southern Observatory, La Silla, Chile. Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses. XIII. Time delays and 9-yr optical monitoring of the lensed quasar RX J1131-1231 Authors: Tewes, M.; Courbin, F.; Meylan, G.; Kochanek, C. S.; Eulaers, E.; Cantale, N.; Mosquera, A. M.; Magain, P.; Van Winckel, H.; Sluse, D.; Cataldi, G.; Vörös, D.; Dye, S. Bibcode: 2013A&A...556A..22T Altcode: 2012arXiv1208.6009T We present the results from nine years of optically monitoring the gravitationally lensed zQSO = 0.658 quasar RX J1131-1231. The R-band light curves of the four individual images of the quasar were obtained using deconvolution photometry for a total of 707 epochs. Several sharp quasar variability features strongly constrain the time delays between the quasar images. Using three different numerical techniques, we measured these delays for all possible pairs of quasar images while always processing the four light curves simultaneously. For all three methods, the delays between the three close images A, B, and C are compatible with being 0, while we measured the delay of image D to be 91 days, with a fractional uncertainty of 1.5% (1σ), including systematic errors. Our analysis of random and systematic errors accounts in a realistic way for the observed quasar variability, fluctuating microlensing magnification over a broad range of temporal scales, noise properties, and seasonal gaps. Finally, we find that our time-delay measurement methods yield compatible results when applied to subsets of the data.

Based on observations made with the 1.2-m Swiss Euler telescope (La Silla, Chile), the 1.3-m SMARTS telescope (Las Campanas, Chile), and the 1.2-m Mercator Telescope. Mercator is operated on the island of La Palma by the Flemish Community, at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.Light curves are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/556/A22 Title: Fast-evolving weather for the coolest of our two new substellar neighbours Authors: Gillon, M.; Triaud, A. H. M. J.; Jehin, E.; Delrez, L.; Opitom, C.; Magain, P.; Lendl, M.; Queloz, D. Bibcode: 2013A&A...555L...5G Altcode: 2013arXiv1304.0481G We present the results of intense photometric monitoring in the near-infrared (~0.9 μm) with the TRAPPIST robotic telescope of the newly discovered binary brown dwarf WISE J104915.57-531906.1, the third closest system to the Sun at a distance of only 2 pc. Our twelve nights of time-series photometry reveal a quasi-periodic (P = 4.87 ± 0.01h) variability with a maximum peak-peak amplitude of ~11% and strong night-to-night evolution. We attribute this variability to the rotational modulation of fast-evolving weather patterns in the atmosphere of the coolest component (~T1-type) of the binary. No periodic signal is detected for the hottest component (~L8-type). For both brown dwarfs, our data allow us to firmly discard any unique transit during our observations for planets ≥2 R⊕. For orbital periods smaller than ~9.5 h, transiting planets are excluded down to an Earth-size. Title: SPECULOOS: Search for habitable Planets EClipsing ULtra-cOOl Stars Authors: Gillon, Michaël; Jehin, Emmanuël; Delrez, Laetitia; Magain, Pierre; Opitom, Cyrielle; Sohy, Sandrine Bibcode: 2013prpl.conf2K066G Altcode: The 1000 nearest ultra-cool stars (spectral type M6 and latter) represent a unique opportunity for the search for life outside our solar system. Due to their small luminosity, their habitable zone is 30-100 times closer than for the Sun, the corresponding orbital periods ranging from one to a few days. Thanks to this proximity, the transits of a habitable planet are much more probable and frequent than for an Earth-Sun analog, while their tiny size (about 1 Jupiter radius) leads to transits deep enough for a ground-based detection, even for sub-Earth size planets. Furthermore, a habitable planet transiting one of these nearby ultra-cool stars would be amenable for a thorough atmospheric characterization, including the detection of possible biosignatures, notably with the near-to-come JWST. Motivated by these reasons, we have set up the concept of a ground-based survey optimized for detecting planets of Earth-size and below transiting the nearest Southern ultra-cool stars. We present here this concept and its status. Title: VizieR Online Data Catalog: The doubly lensed quasar SDSS J1001+5027 (Rathna Kumar+, 2013) Authors: Rathna, Kumar S.; Tewes, M.; Stalin, C. S.; Courbin, F.; Asfandiyarov, I.; Meylan, G.; Eulaers, E.; Prabhu, T. P.; Magain, P.; van Winckel, H.; Ehgamberdiev, Sh. Bibcode: 2013yCat..35570044R Altcode: 2013yCat..35579044R These data are R-band light curves of the doubly lensed quasar SDSS J1001+5027, as displayed in Fig. 4 of the paper. They cover 6.5 years, from March 2005 to July 2011.

The light curves are obtained using deconvolution photometry of images from 3 different telescopes, for a total of 443 epochs. Several quasar variability features strongly constrain the time delay between the quasar images.

(1 data file). Title: VizieR Online Data Catalog: R-band light curves of RX J1131-1231 (Tewes+, 2013) Authors: Tewes, M.; Courbin, F.; Meylan, G.; Kochanek, C. S.; Eulaers, E.; Cantale, N.; Mosquera, A. M.; Magain, P.; van Winckel, H.; Sluse, D.; Cataldi, G.; Voros, D.; Dye, S. Bibcode: 2013yCat..35560022T Altcode: 2013yCat..35569022T We have been monitoring the quadruply lensed quasar RX J1131-1231 since December 2003 with different telescopes in the R band (~600-720nm). The resulting R-band light curves of the quadruply lensed quasar RX J1131-1231, is displayed in Fig. 4 of the paper.

The light curves are obtained using deconvolution photometry of images from 3 different telescopes (the ESO Euler 1.2m, the CTIO SMARTS 1.3m and the Mercator 1.2m), for a total of 707 epochs. Several sharp quasar variability features strongly constrain the time delays between the quasar images.

(1 data file). Title: The Nebula around the Luminous Blue Variable WRAY 15-751 as seen by Herschel Authors: Vamvatira-Nakou, C.; Hutsemekers, D.; Royer, P.; Naze, Y.; Magain, P.; Exter, K.; Waelkens, C.; Groenewegen, M. Bibcode: 2013msao.confE.188V Altcode: To understand the evolution of massive stars it is crucial to study the nebulae associated to Luminous Blue Variables which can reveal the star mass-loss history. We obtained far-infrared Herschel PACS imaging and spectroscopic observations of the nebula associated with the Luminous Blue Variable star WRAY 15-751. These images revealed a second nebula, bigger and cooler, lying in an empty cavity that probably delineates the remnant of the O-star bubble formed when the star was on the Main Sequence. The dust mass and temperature were derived from the modeling of the far-infrared SED. The analysis of the emission line spectrum revealed that the main nebula consists of a region of photoionised gas surrounded by a thin photodissociation region. Both regions are mixed with dust. The calculated C, N, O abundances, together with the estimated mass-loss rate, show that the nebula was ejected from the star during a Red Supergiant phase. This is compatible with the latest evolutionary tracks for a ~40 Mo star with little rotation. Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses. XII. Time delays of the doubly lensed quasars SDSS J1206+4332 and HS 2209+1914 Authors: Eulaers, E.; Tewes, M.; Magain, P.; Courbin, F.; Asfandiyarov, I.; Ehgamberdiev, Sh.; Rathna Kumar, S.; Stalin, C. S.; Prabhu, T. P.; Meylan, G.; Van Winckel, H. Bibcode: 2013A&A...553A.121E Altcode: 2013arXiv1304.4474E
Aims: Within the framework of the COSMOGRAIL collaboration we present 7- and 8.5-year-long light curves and time-delay estimates for two gravitationally lensed quasars: SDSS J1206+4332 and HS 2209+1914.
Methods: We monitored these doubly lensed quasars in the R-band using four telescopes: the Mercator, Maidanak, Himalayan Chandra, and Euler telescopes, together spanning a period of 7 to 8.5 observing seasons from mid-2004 to mid-2011. The photometry of the quasar images was obtained through simultaneous deconvolution of these data. The time delays were determined from these resulting light curves using four very different techniques: a dispersion method, a spline fit, a regression difference technique, and a numerical model fit. This minimizes the bias that might be introduced by the use of a single method.
Results: The time delay for SDSS J1206+4332 is ΔtAB = 111.3 ± 3 days with A leading B, confirming a previously published result within the error bars. For HS 2209+1914 we present a new time delay of ΔtBA = 20.0 ± 5 days with B leading A.
Conclusions: The combination of data from up to four telescopes have led to well-sampled and nearly 9-season-long light curves, which were necessary to obtain these results, especially for the compact doubly lensed quasar HS 2209+1914.

Based on observations made with the 1.2-m Swiss Euler telescope (La Silla, Chile), the 1.5-m AZT-22 telescope (Maidanak Observatory, Uzbekistan), the 2.0-m HCT telescope (Hanle, India), and the 1.2-m Mercator Telescope. Mercator is operated on the island of La Palma by the Flemish Community, at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.Numerical values of light curves are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/553/A121 and at http://www.cosmograil.org Title: VizieR Online Data Catalog: 2 lensed quasars light curves (Eulaers+, 2013) Authors: Eulaers, E.; Tewes, M.; Magain, P.; Courbin, F.; Asfandiyarov, I.; Ehgamberdiev, Sh.; Rathna, Kumar S.; Stalin, C. S.; Prabhu, T. P.; Meylan, G.; van Winckel, H. Bibcode: 2013yCat..35530121E Altcode: 2013yCat..35539121E Within the framework of the COSMOGRAIL collaboration we present 7- and 8.5-year-long light curves and time-delay estimates for two gravitationally lensed quasars: SDSS J1206+4332 and HS 2209+1914.

We monitored these doubly lensed quasars in the R-band using four telescopes: the Mercator, Maidanak, Himalayan Chandra, and Euler Telescopes, together spanning a period of 7 to 8.5 observing seasons from mid-2004 to mid-2011. The photometry of the quasar images was obtained through simultaneous deconvolution of these data. The time delays were determined from these resulting light curves using four very different techniques: a dispersion method, a spline fit, a regression difference technique, and a numerical model fit. This minimizes the bias that might be introduced by the use of a single method.

(2 data files). Title: TRAPPIST-UCDTS: A prototype search for habitable planets transiting ultra-cool stars Authors: Gillon, M.; Jehin, E.; Fumel, A.; Magain, P.; Queloz, D. Bibcode: 2013EPJWC..4703001G Altcode: The ∼1000 nearest ultra-cool stars (spectral type M6 and latter) represent a unique opportunity for the search for life outside solar system. Due to their small luminosity, their habitable zone is 30-100 times closer than for the Sun, the corresponding orbital periods ranging from one to a few days. Thanks to this proximity, the transits of a habitable planet are much more probable and frequent than for an Earth-Sun analog, while their tiny size (∼1 Jupiter radius) leads to transits deep enough for a ground-based detection, even for sub-Earth size planets. Furthermore, a habitable planet transiting one of these nearby ultra-cool star would be amenable for a thorough atmospheric characterization, including the detection of possible biosignatures, notably with the near-to-come JWST. Motivated by these reasons, we have set up the concept of a ground-based survey optimized for detecting planets of Earth-size and below transiting the nearest Southern ultra-cool stars. To assess thoroughly the actual potential of this future survey, we are currently conducting a prototype mini-survey using the TRAPPIST robotic 60cm telescope located at La Silla ESO Observatory (Chile). We summarize here the preliminary results of this mini-survey that fully validate our concept. Title: Gravitational lensing evidence against extended dark matter halos Authors: Magain, Pierre; Chantry, Virginie Bibcode: 2013arXiv1303.6896M Altcode: It is generally thought that galaxies are embedded in dark matter halos extending well beyond their luminous matter. The existence of these galactic halos is mainly derived from the larger than expected velocities of stars and gas in the outskirts of spiral galaxies. Much less is known about dark matter around early-type (elliptical or lenticular) galaxies. We use gravitational lensing to derive the masses of early-type galaxies deflecting light of background quasars. This provides a robust measurement of the total mass within the Einstein ring, a circle whose diameter is comparable to the separation of the different quasar images. We find that the mass-to-light ratio of the lensing galaxies does not depend on radius, from inner galactic regions out to several half-light radii. Moreover, its value does not exceed the value predicted by stellar population models by more than a factor two, which may be explained by baryonic dark matter alone, without any need for exotic matter. Our results thus suggest that, if dark matter is present in early-type galaxies, its amount does not exceed the amount of luminous matter and its density follows that of luminous matter, in sharp contrast to what is found from rotation curves of spiral galaxies. Title: COSMOGRAIL: Time delays in lensed quasars from Himalayan Chandra Telescope Authors: Rathna Kumar, S.; Stalin, C. S.; Tewes, M.; Courbin, F.; Asfandiyarov, I.; Ibrahimov, M.; Eulaers, E.; Meylan, G.; Prabhu, T. P.; Magain, P. Bibcode: 2013ASInC...9...87R Altcode: Estimating H_0 to an accuracy of few percent is an important challenge today as it will offer key insights into various questions in cosmology. By measuring time delays between the photometric variations in lensed quasar images and subsequent modelling of the mass distribution in the lensing galaxy, it is possible to constrain H_0 in a way well complementary to traditional techniques. Time delays are difficult to measure due to the long time span needed to monitor the sources and photometry is challenging due to the small angular separation between the lensed quasar images. These issues are addressed by the COSMOGRAIL (COSmological MOnitoring of GRAvItational Lenses) collaboration, which uses several telescopes in both the hemispheres to monitor a large sample of gravitationally lensed quasars. As part of this collaboration, 6 sources are being monitored using the 2 m Himalayan Chandra Telescope (HCT) in Hanle, India. We present here the preliminary estimates of time delays in these sources. Title: COSMOGRAIL: Measuring Time Delays of Gravitationally Lensed Quasars to Constrain Cosmology Authors: Tewes, M.; Courbin, F.; Meylan, G.; Kochanek, C. S.; Eulaers, E.; Cantale, N.; Mosquera, A. M.; Asfandiyarov, I.; Magain, P.; van Winckel, H.; Sluse, D.; Keerthi, R. K. S.; Stalin, C. S.; Prabhu, T. P.; Saha, P.; Dye, S. Bibcode: 2012Msngr.150...49T Altcode: COSMOGRAIL is a long-term programme for the photometric monitoring of gravitationally lensed quasars. It makes use of several medium-size telescopes to derive long and well-sampled light curves of lensed quasars, in order to measure the time delays between the quasar images. These delays directly relate to the Hubble constant H0, without any need for secondary distance calibrations. COSMOGRAIL was initiated in 2004, and has now secured almost a decade of data, resulting in cosmological constraints that are very complementary to other cosmological probes. Title: An expanding universe without dark matter and dark energy Authors: Magain, Pierre Bibcode: 2012arXiv1212.1110M Altcode: Assuming that observers located inside the Universe measure a time flow which is different from the time appearing in the Friedmann-Lemaitre equation, and determining this time flow such that the Universe always appears flat to these observers, we derive a simple cosmological model which allows to explain the velocity dispersions of galaxies in galaxy clusters without introducing dark matter. It also solves the horizon problem without recourse to inflation. Moreover, it explains the present acceleration of the expansion without any resort to dark energy and provides a good fit to the observations of distant supernovae. Depending on the present value of the matter-energy density, we calculate an age of the Universe between 15.4 and 16.5 billion years, significantly larger than the 13.7 billion years of the standard Lambda-CDM model. Our model has a slower expansion rate in the early epochs, thus leaving more time for the formation of structures such as stars and galaxies. Title: Minor Planet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2012MPC..81457..12J Altcode: No abstract at ADS Title: Debris disks as seen by Herschel/DUNES Authors: Löhne, T.; Eiroa, C.; Augereau, J. -C.; Ertel, S.; Marshall, J. P.; Mora, A.; Absil, O.; Stapelfeldt, K.; Thébault, P.; Bayo, A.; del Burgo, C.; Danchi, W.; Krivov, A. V.; Lebreton, J.; Letawe, G.; Magain, P.; Maldonado, J.; Montesinos, B.; Pilbratt, G. L.; White, G. J.; Wolf, S. Bibcode: 2012AN....333..441L Altcode: The far-infrared excesses produced by debris disks are common features of stellar systems. These disks are thought to contain solids ranging from micron-sized dust to planetesimals. Naturally, their formation and evolution are linked to those of potential planets. With this motivation, the Herschel open time key programme DUNES (DUst around NEarby Stars) aims at further characterising known debris disks and discovering new ones in the regime explored by the Herschel space observatory. On the one hand, in their survey of 133 nearby FGK stars, DUNES discovered a class of extremely cold and faint debris disks, different from well-known disks such as the one around Vega in that their inferred typical grain sizes are rather large, indicating low dynamical excitation and low collision rates. On the other hand, for the more massive disk around the sun-like star HD 207129, well-resolved PACS images confirmed the ring-liked structure seen in HST images and provided valuable information for an in-depth study and benchmark for models. Employing both models for power-law fitting and collisional evolution we found the disk around HD 207129 to feature low collision rates and large grains, as well. Transport by means of Poynting-Robertson drag likely plays a role in replenishing the dust seen closer to the star, inside of the ring. The inner edge is therefore rather smooth and the contribution from the extended halo of barely bound grains is small. Both slowly self-stirring and planetary perturbations could potentially have formed and shaped this disk.

Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. Title: The TRAPPIST survey of southern transiting planets. I. Thirty eclipses of the ultra-short period planet WASP-43 b Authors: Gillon, M.; Triaud, A. H. M. J.; Fortney, J. J.; Demory, B. -O.; Jehin, E.; Lendl, M.; Magain, P.; Kabath, P.; Queloz, D.; Alonso, R.; Anderson, D. R.; Collier Cameron, A.; Fumel, A.; Hebb, L.; Hellier, C.; Lanotte, A.; Maxted, P. F. L.; Mowlavi, N.; Smalley, B. Bibcode: 2012A&A...542A...4G Altcode: 2012arXiv1201.2789G We present twenty-three transit light curves and seven occultation light curves for the ultra-short period planet WASP-43 b, in addition to eight new measurements of the radial velocity of the star. Thanks to this extensive data set, we improve significantly the parameters of the system. Notably, the largely improved precision on the stellar density (2.41 ± 0.08 ρ⊙) combined with constraining the age to be younger than a Hubble time allows us to break the degeneracy of the stellar solution mentioned in the discovery paper. The resulting stellar mass and size are 0.717 ± 0.025 M⊙ and 0.667 ± 0.011 R⊙. Our deduced physical parameters for the planet are 2.034 ± 0.052 MJup and 1.036 ± 0.019 RJup. Taking into account its level of irradiation, the high density of the planet favors an old age and a massive core. Our deduced orbital eccentricity, 0.0035-0.0025+0.0060, is consistent with a fully circularized orbit. We detect the emission of the planet at 2.09 μm at better than 11-σ, the deduced occultation depth being 1560 ± 140 ppm. Our detection of the occultation at 1.19 μm is marginal (790 ± 320 ppm) and more observations are needed to confirm it. We place a 3-σ upper limit of 850 ppm on the depth of the occultation at ~0.9 μm. Together, these results strongly favor a poor redistribution of the heat to the night-side of the planet, and marginally favor a model with no day-side temperature inversion.

Based on data collected with the TRAPPIST and Euler telescopes at ESO La Silla Observatory, Chile, and with the VLT/HAWK-I instrument at ESO Paranal Observatory, Chile (program 086.C-0222).Tables 1 and 4 are available in electronic form at http://www.aanda.orgPhotometry is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/542/A4 Title: VizieR Online Data Catalog: WASP-43b thirty eclipses (Gillon+, 2012) Authors: Gillon, M.; Triaud, A. H. M. J.; Fortney, J. J.; Demory, B. -O.; Jehin, E.; Lendl, M.; Magain, P.; Kabath, P.; Queloz, D.; Alonso, R.; Anderson, D. R.; Collier, Cameron A.; Fumel, A.; Hebb, L.; Hellier, C.; Lanotte, A.; Maxted, P. F. L.; Mowlavi, N.; Smalley, B. Bibcode: 2012yCat..35420004G Altcode: 2012yCat..35429004G We present photometric time-series obtained by the TRAPPIST, Euler and VLT telescopes.

(4 data files). Title: Minor Planet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2012MPC..79337...9J Altcode: No abstract at ADS Title: Minor Planet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2012MPC..79015...3J Altcode: No abstract at ADS Title: Comet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2012MPC..78279..27J Altcode: No abstract at ADS Title: Minor Planet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2012MPC..78580...7J Altcode: No abstract at ADS Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses. X. Modeling based on high-precision astrometry of a sample of 25 lensed quasars: consequences for ellipticity, shear, and astrometric anomalies Authors: Sluse, D.; Chantry, V.; Magain, P.; Courbin, F.; Meylan, G. Bibcode: 2012A&A...538A..99S Altcode: 2011arXiv1112.0005S Gravitationally lensed quasars can be used as powerful cosmological and astrophysical probes. We can (i) infer the Hubble constant H0 based on the so-called time-delay technique, (ii) unveil substructures along the line-of-sight toward distant galaxies, and (iii) compare the shape and the slope of baryons and dark matter distributions in the inner regions of galaxies. To reach these goals, we need high-accuracy astrometry of the quasar images relative to the lensing galaxy and morphology measurements of the lens. In this work, we first present new astrometry for 11 lenses with measured time delays, namely, JVAS B0218+357, SBS 0909+532, RX J0911.4+0551, FBQS J0951+2635, HE 1104-1805, PG 1115+080, JVAS B1422+231, SBS 1520+530, CLASS B1600+434, CLASS B1608+656, and HE 2149-2745. These measurements proceed from the use of the Magain-Courbin-Sohy (MCS) deconvolution algorithm applied in an iterative way (ISMCS) to near-IR HST images. We obtain a typical astrometric accuracy of about 1-2.5 mas and an accurate shape measurement of the lens galaxy. Second, we combined these measurements with those of 14 other lensing systems, mostly from the COSMOGRAIL set of targets, to present new mass models of these lenses. The modeling of these 25 gravitational lenses led to the following results: 1) in four double-image quasars (HE0047-1746, J1226-006, SBS 1520+530, and HE 2149-2745), we show that the influence of the lens environment on the time delay can easily be quantified and modeled, hence putting these lenses with high priority for time-delay determination; 2) for quadruple-image quasars, the difficulty often encountered in reproducing the image positions to milli-arcsec accuracy (astrometric anomaly problem) is overcome by explicitly including the nearest visible galaxy/satellite in the lens model. However, one anomalous system (RXS J1131-1231) does not show any luminous perturber in its vicinity, and three others (WFI 2026-4536, WFI 2033-4723, and B2045+265) have problematic modeling. These four systems are the best candidates for a pertubation by a dark matter substructure along the line-of-sight; 3) we revisit the correlation between the position angle (PA) and ellipticity of the light and of the mass distribution in lensing galaxies. As in previous studies, we find a significant correlation between the PA of the light and of the mass distributions. However, in contrast with these same studies, we find that the ellipticity of the light and of the mass also correlate well, suggesting that the overall spatial distribution of matter is not very different from the baryon distribution in the inner ~5 kpc of lensing galaxies. This offers a new test for high-resolution hydrodynamical simulations.

Based on observations made with the NASA/ESA HST Hubble Space Telescope by the CfA-Arizona Space Telescope Lens Survey (CASTLeS) collaboration, obtained from the data archive at the Space Science Institute, which is operated by AURA, the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS-5-26555. Title: Comet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2012MPC..77877..22J Altcode: No abstract at ADS Title: Minor Planet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2012MPC..78177...3J Altcode: No abstract at ADS Title: Observations and Orbits of Comets Authors: Kostov, A.; Vassileva, L.; Vales, J.; Gajdos, S.; Vilagi, J.; Foglia, S.; Galli, G.; Buzzi, L.; Naves, R.; Campas, M.; Ligustri, R.; Abe, H.; Seki, T.; Bill, H.; Arnold, L.; Kelemen, J.; Micheli, M.; Elliott, G. T.; Tholen, D. J.; Baransky, A.; Hergenrother, C. W.; Gibbs, A. R.; Ahern, J. D.; Beshore, E. C.; Boattini, A.; Garradd, G. J.; Tricarico, P.; Grauer, A. D.; Hill, R. E.; Kowalski, R. A.; Larson, S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.; Gall, C.; Melita, M. D.; Durig, D. T.; Liu, H.; Ikari, Y.; Castellano, J.; Dupouy, P.; Jaeger, M.; Prosperi, E.; Vollmann, W.; Andreev, M.; Emelyanenko, V.; Sergeev, A.; Parakhin, N.; Kozlov, V.; Karpov, N.; Nevski, V.; Nicolas, J.; Lopesino, J.; Borghini, W.; Bosch, J. M.; Olivera, R. M.; Martignoni, M.; Bryssinck, E.; Diepvens, A.; Gerke, V.; Plaksa, S.; Novichonok, A.; Chestnov, D.; Xu, Z.; Gao, X.; Grau Horta, F.; Gaitan, J.; Brusa, M.; Sempio, L.; Ohshima, Y.; Sugiyama, Y.; Hills, K.; Yusa, T.; Koshikawa, M.; Takahashi, T.; Primak, N.; Schultz, A.; Watters, S.; Thiel, J.; Goggia, T.; Dymock, R.; Sato, H.; Guido, E.; Sostero, G.; Howes, N.; Kiyota, S.; Haugh, T.; Sherrod, P. C.; Bell, C.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Masek, M.; Cerny, J.; Ebr, J.; Prouza, M.; Kubanek, P.; Jelinek, M.; Martin, J. L.; Gonzalez, J.; Carreno, A.; Piqueras, J.; Pena Ciriza, F.; Garcia, F.; Henriquez, J. A.; Birtwhistle, P.; Climent, T.; Williams, G. V. Bibcode: 2012MPEC....D...09K Altcode: No abstract at ADS Title: Modelling the huge, Herschel-resolved debris ring around HD 207129 Authors: Löhne, T.; Augereau, J. -C.; Ertel, S.; Marshall, J. P.; Eiroa, C.; Mora, A.; Absil, O.; Stapelfeldt, K.; Thébault, P.; Bayo, A.; Del Burgo, C.; Danchi, W.; Krivov, A. V.; Lebreton, J.; Letawe, G.; Magain, P.; Maldonado, J.; Montesinos, B.; Pilbratt, G. L.; White, G. J.; Wolf, S. Bibcode: 2012A&A...537A.110L Altcode: Debris disks, which are inferred from the observed infrared excess to be ensembles of dust, rocks, and probably planetesimals, are common features of stellar systems. As the mechanisms of their formation and evolution are linked to those of planetary bodies, they provide valuable information. The few well-resolved debris disks are even more valuable because they can serve as modelling benchmarks and help resolve degeneracies in modelling aspects such as typical grain sizes and distances. Here, we present an analysis of the HD 207129 debris disk, based on its well-covered spectral energy distribution and Herschel/PACS images obtained in the framework of the DUNES (DUst around NEarby Stars) programme. We use an empirical power-law approach to the distribution of dust and we then model the production and removal of dust by means of collisions, direct radiation pressure, and drag forces. The resulting best-fit model contains a total of nearly 10-2 Earth masses in dust, with typical grain sizes in the planetesimal belt ranging from 4 to 7 μm. We constrain the dynamical excitation to be low, which results in very long collisional lifetimes and a drag that notably fills the inner gap, especially at 70 μm. The radial distribution stretches from well within 100 AU in an unusual, outward-rising slope towards a rather sharp outer edge at about 170-190 AU. The inner edge is therefore smoother than that reported for Fomalhaut, but the contribution from the extended halo of barely bound grains is similarly small. Both slowly self-stirring and planetary perturbations could potentially have formed and shaped this disk.

Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. Title: Observations and Orbits of Comets Authors: Bacci, P.; Tesi, L.; Fagioli, G.; Jaeger, M.; Prosperi, E.; Vollmann, W.; Foglia, S.; Galli, G.; Naves, R.; Campas, M.; Ligustri, R.; Seki, T.; Shimomoto, S.; Sato, H.; Boattini, A.; Ahern, J. D.; Beshore, E. C.; Garradd, G. J.; Gibbs, A. R.; Tricarico, P.; Grauer, A. D.; Hill, R. E.; Kowalski, R. A.; Larson, S. M.; McNaught, R. H.; Bezpalko, M.; Torres, D.; Kracke, R.; Spitz, G.; Kistler, J.; Stuart, J.; Scruggs, S.; Ikari, Y.; Vidal, J. R.; Nicolas, J.; Lopesino, J.; Martignoni, M.; Bryssinck, E.; Soulier, J. F.; Diepvens, A.; Grau Horta, F.; Tremosa, L.; Brusa, M.; Sempio, L.; Ohshima, Y.; Hills, K.; Takahashi, T.; Camilleri, P.; Primak, N.; Schultz, A.; Watters, S.; Thiel, J.; Goggia, T.; Guido, E.; Howes, N.; Sostero, G.; Dymock, R.; Ryan, E. L.; Shappee, B.; Thompson, D.; Woodward, C. E.; Elenin, L.; Sherrod, P. C.; Ambrosioni Prosen, C.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Buczynski, D.; Limon, F.; Gonzalez, J.; Garcia, F.; Henriquez, J. A.; Climent, T.; Williams, G. V. Bibcode: 2012MPEC....A...52B Altcode: No abstract at ADS Title: Observations and Orbits of Comets Authors: Kostov, A.; Vassileva, L.; Bacci, P.; Vergari, S.; Tesi, L.; Fagioli, G.; Zakrajsek, J.; Casali, M.; Coffano, A.; Marinello, W.; Micheli, M.; Pizzetti, G.; Antonini, P.; Haver, R.; Gorelli, R.; Jaeger, M.; Prosperi, E.; Vollmann, W.; Buzzi, L.; Naves, R.; Campas, M.; Hasubick, W.; Ligustri, R.; Nishiyama, K.; Hashimoto, N.; Kadota, K.; Seki, T.; Shimomoto, S.; Sato, H.; Bill, H.; Arnold, L.; Baransky, A.; Barinova, K.; Vorontseva, A.; Pettarin, E.; Grauer, A. D.; Hill, R. E.; Ahern, J. D.; Beshore, E. C.; Boattini, A.; Garradd, G. J.; Gibbs, A. R.; Tricarico, P.; Kowalski, R. A.; Larson, S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.; Gall, C.; Durig, D. T.; Ikari, Y.; Castellano, J.; Dymock, R.; Vidal, J. R.; Karami, M.; Fathivavsari, H.; Vaduvescu, O.; Bryssinck, E.; Linder, J.; Nicolas, J.; Martignoni, M.; Haeusler, B.; Noel, T.; Diepvens, A.; Zilch, T.; Gerke, V.; Novichonok, A.; Steffl, A.; Tremosa, L.; Caimmi, M.; Balanutsa, P.; Lipunov, V.; Zimnukhov, D.; Gorbovskoy, E.; Shurpakov, S.; Hills, K.; Koishikawa, M.; Takahashi, T.; Herald, D.; Camilleri, P.; Drummond, J.; Guido, E.; Sostero, G.; Howes, N.; Sherrod, P. C.; Bell, C.; Ortiz, J. L.; Morales, N.; de, I.; Ambrosioni Prosen, C.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Buczynski, D.; Limon, F.; Gonzalez, J.; Rinner, C.; Kugel, F.; Benkhaldoun, Z.; Muler, G.; Ruiz, J. M.; Williams, G. V. Bibcode: 2012MPEC....B...23K Altcode: No abstract at ADS Title: Observations and Orbits of Comets Authors: Vilagi, J.; Kornos, L.; Casali, M.; Coffano, A.; Marinello, W.; Micheli, M.; Pizzetti, G.; Jaeger, M.; Prosperi, E.; Vollmann, W.; Foglia, S.; Galli, G.; Buzzi, L.; Naves, R.; Campas, M.; Hasubick, W.; Ligustri, R.; Kadota, K.; Seki, T.; Shimomoto, S.; Sato, H.; Baransky, A.; Barinova, K.; Vorobjov, T.; Kowalski, R. A.; Gibbs, A. R.; Ahern, J. D.; Beshore, E. C.; Boattini, A.; Garradd, G. J.; Tricarico, P.; Grauer, A. D.; Hill, R. E.; Larson, S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.; Gall, C.; Durig, D. T.; Duddlesten, A. J.; Cardamone, C. J.; Simpkins, H. R.; Lopez, J. O.; Clements, R. R.; Gardner, M. M.; Jenkins, R. E.; Bailey, E. T.; Miedaner, K. E.; Stitts, M. R.; Ikari, Y.; Castellano, J.; Vidal, J. R.; Dupouy, P.; James, N.; Cozzi, E.; Kugel, F.; Franco, L.; Bryssinck, E.; Garrigos Sanchez, A.; Nicolas, J.; Lopesino, J.; Borghini, W.; Bosch, J. M.; Olivera, R. M.; Martignoni, M.; Haeusler, B.; Diepvens, A.; Hui, M. -T.; Gao, X.; Tremosa, L.; Ohshima, Y.; Hills, K.; Koishikawa, M.; Takahashi, T.; Herald, D.; Primak, N.; Schultz, A.; Watters, S.; Thiel, J.; Goggia, T.; Guido, E.; Sostero, G.; Howes, N.; Elenin, L.; Sherrod, P. C.; Ambrosioni Prosen, C.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Masek, M.; Cerny, J.; Ebr, J.; Prouza, M.; Kubanek, P.; Jelinek, M.; Buczynski, D.; Carrillo, J.; Limon, F.; Gonzalez, J.; Pena Ciriza, F.; Baez, J.; Garcia, F.; Muler, G.; Ruiz, J. M.; Williams, G. V. Bibcode: 2012MPEC....B...78V Altcode: No abstract at ADS Title: Time delays for eleven gravitationally lensed quasars revisited Authors: Eulaers, E.; Magain, P. Bibcode: 2011A&A...536A..44E Altcode: 2011arXiv1112.2609E
Aims: We test the robustness of published time delays for 11 lensed quasars by using two techniques to measure time shifts in their light curves.
Methods: We chose to use two fundamentally different techniques to determine time delays in gravitationally lensed quasars: a method based on fitting a numerical model and another one derived from the minimum dispersion method introduced by Pelt and collaborators. To analyse our sample in a homogeneous way and avoid bias caused by the choice of the method used, we apply both methods to 11 different lensed systems for which delays have been published: JVAS B0218+357, SBS 0909+523, RX J0911+0551, FBQS J0951+2635, HE 1104-1805, PG 1115+080, JVAS B1422+231, SBS 1520+530, CLASS B1600+434, CLASS B1608+656, and HE 2149-2745
Results: Time delays for three double lenses, JVAS B0218+357, HE 1104-1805, and CLASS B1600+434, as well as the quadruply lensed quasar CLASS B1608+656 are confirmed within the error bars. We correct the delay for SBS 1520+530. For PG 1115+080 and RX J0911+0551, the existence of a second solution on top of the published delay is revealed. The time delays in four systems, SBS 0909+523, FBQS J0951+2635, JVAS B1422+231, and HE 2149-2745 prove to be less reliable than previously claimed.
Conclusions: If we wish to derive an estimate of H0 based on time delays in gravitationally lensed quasars, we need to obtain more robust light curves for most of these systems in order to achieve a higher accuracy and robustness on the time delays. Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses. IX. Time delays, lens dynamics and baryonic fraction in HE 0435-1223 Authors: Courbin, F.; Chantry, V.; Revaz, Y.; Sluse, D.; Faure, C.; Tewes, M.; Eulaers, E.; Koleva, M.; Asfandiyarov, I.; Dye, S.; Magain, P.; van Winckel, H.; Coles, J.; Saha, P.; Ibrahimov, M.; Meylan, G. Bibcode: 2011A&A...536A..53C Altcode: 2010arXiv1009.1473C We present accurate time delays for the quadruply imaged quasar HE 0435-1223. The delays were measured from 575 independent photometric points obtained in the R-band between January 2004 and March 2010. With seven years of data, we clearly show that quasar image A is affected by strong microlensing variations and that the time delays are best expressed relative to quasar image B. We measured ΔtBC = 7.8 ± 0.8 days, ΔtBD = -6.5 ± 0.7 days and ΔtCD = -14.3 ± 0.8 days. We spacially deconvolved HST NICMOS2 F160W images to derive accurate astrometry of the quasar images and to infer the light profile of the lensing galaxy. We combined these images with a stellar population fitting of a deep VLT spectrum of the lensing galaxy to estimate the baryonic fraction, fb, in the Einstein radius. We measured fb = 0.65-0.10+0.13 if the lensing galaxy has a Salpeter IMF and fb = 0.45-0.07+0.04 if it has a Kroupa IMF. The spectrum also allowed us to estimate the velocity dispersion of the lensing galaxy, σap = 222 ± 34 km s-1. We used fb and σap to constrain an analytical model of the lensing galaxy composed of an Hernquist plus generalized NFW profile. We solved the Jeans equations numerically for the model and explored the parameter space under the additional requirement that the model must predict the correct astrometry for the quasar images. Given the current error bars on fb and σap, we did not constrain H0 yet with high accuracy, i.e., we found a broad range of models with χ2 < 1. However, narrowing this range is possible, provided a better velocity dispersion measurement becomes available. In addition, increasing the depth of the current HST imaging data of HE 0435-1223 will allow us to combine ourconstraints with lens reconstruction techniques that make use of the full Einstein ring that is visible in this object.

Based on observations made with the 1.2 m Euler Swiss Telescope, the 1.5 m telescope of Maidanak Observatory in Uzbekistan, and with the 1.2 m Mercator Telescope, operated on the island of La Palma by the Flemish Community, at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. The NASA/ESA Hubble Space Telescope data was obtained from the data archive at the Space Telescope Science Institute, which is operated by AURA, the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS-5-26555.Light curves are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/536/A53 Title: New Insights into the Quasar Type 1/Type 2 Dichotomy from Correlations between Quasar Host Orientation and Polarization Authors: Borguet, B.; Hutsemékers, D.; Letawe, G.; Letawe, Y.; Magain, P. Bibcode: 2011ASPC..449..459B Altcode: 2008arXiv0809.4539B We investigate correlations between the direction of the optical linear polarization and the orientation of the host galaxy/extended emission for type 1 and type 2 radio-loud and radio-quiet quasars. We have used high resolution Hubble Space Telescope data and a deconvolution process to obtain a good determination of the host galaxy/extended emission (EE) position angle. With these new measurements and a compilation of data from the literature, we find a significant correlation, different for type 1 and type 2 objects, between the linear polarization position angle and the orientation of the EE, suggesting scattering by an extended UV/blue region in both types of objects. Our observations support the extension of the Unification Model to the higher luminosity AGNs like the quasars, assuming a two component scattering model. Title: Minor Planet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2011MPC..77008...8J Altcode: No abstract at ADS Title: Comet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2011MPC..76684...9J Altcode: No abstract at ADS Title: Observations and Orbits of Comets Authors: Sybiryakova, Y.; Kozyryev, Y.; Kulichenko, N.; Vovk, V.; Shulga, O.; Cernis, K.; Zdanavicius, J.; Haver, R.; Buzzi, L.; Naves, R.; Campas, M.; Hasubick, W.; Donati, S.; Meyer, M.; Scotti, J. V.; Kadota, K.; Asami, A.; Abe, H.; Seki, T.; Shimomoto, S.; Sato, H.; Wakuda, S.; Bill, H.; Arnold, L.; Micheli, M.; Elliott, G. T.; Tholen, D. J.; Kashuba, S.; Kashuba, V.; Gorbanev, Y.; Podlesnyak, S.; Stogneeva, I.; Baransky, A.; Barinova, K.; Markov, Y.; Vorontseva, A.; Bressi, T. H.; Hergenrother, C. W.; Kowalski, R. A.; Hill, R. E.; Boattini, A.; Ahern, J. D.; Beshore, E. C.; Garradd, G. J.; Gibbs, A. R.; Tricarico, P.; Grauer, A. D.; Larson, S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.; Gall, C.; Moritz, N.; Elliott, R.; Durig, D. T.; Roberts, C. A.; Smith, C. M.; Dziminski, H. T.; Ikari, Y.; Vidal, J. R.; Dupouy, P.; Jaeger, M.; Prosperi, E.; Prosperi, S.; Vollmann, W.; Shurpakov, S.; Bacci, P.; Antonacci, D.; Nevski, V.; Linder, J.; Nicolas, J.; Lopesino, J.; Overhaus, C.; Haeusler, B.; Novichonok, A.; Agletdinov, V.; Mezentsev, A.; Ignahin, V.; Bryssinck, E.; Veselkov, S.; Bros, X.; Soulier, J. F.; Diepvens, A.; Zilch, T.; Gerke, V.; Plaksa, S.; Chestnov, D.; Lindner, P.; Tudorica, A.; Badescu, T.; Rosicarelli, M.; Capella, E.; Gaitan, J.; Zhao, H. B.; Yao, J. S.; Zhaori, G. T.; Lu, H.; Wang, M.; Hong, R. Q.; Hu, L. F.; Xia, Y.; Ohshima, Y.; Hills, K.; Takahashi, T.; Camilleri, P.; Primak, N.; Schultz, A.; Watters, S.; Thiel, J.; Goggia, T.; Dymock, R.; Elenin, L.; Sherrod, P. C.; Bell, C.; Ortiz, J. L.; Morales, N.; de, I.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Fraga, A.; Limon, F.; Gonzalez, J.; Baez, J.; Garcia, F.; Canales, O.; Fletcher, J.; Williams, G. V. Bibcode: 2011MPEC....V...31S Altcode: No abstract at ADS Title: Long term photometric monitoring of comet 103P/Hartley2 with the new robotic TRAPPIST telescope Authors: Jehin, E.; Manfroid, J.; Hutsemékers, D.; Gillon, M.; Magain, P. Bibcode: 2011epsc.conf.1489J Altcode: 2011DPS....43.1489J; 2011epsc.conf.1479J We report on a long term monitoring of comet 103P/Hartley2 with six cometary narrow band filters using the TRAPPIST 0.60m telescope installed recently at the ESO La Silla observatory in Chile. This new robotic telescope is dedicated to exoplanet and solar system research. The comet was observed with the cometary filters during 4 months, from Oct. 29 to Feb. 22. Since then the monitoring continues but only through the BVRI filters and about two times per week. Those observations allowed us to make a detailed light curve of the comet after its perihelion passage and derive production rates of the 4 main species (OH, CN, C2, C3) as well as the dust production rate (Afρ) over that period. The high sampling of our monitoring allowed us to find a periodicity in the gaseous light curves and to deduce a rotation period of 18.4h early November, slowing down to about 19h by the end of December. Title: VizieR Online Data Catalog: R-band light curves of HE 0435-1223 (Courbin+, 2011) Authors: Courbin, F.; Chantry, V.; Revaz, Y.; Sluse, D.; Faure, C.; Tewes, M.; Eulaers, E.; Koleva, M.; Asfandiyarov, I.; Dye, S.; Magain, P.; van Winckel, H.; Coles, J.; Saha, P.; Ibrahimov, M.; Meylan, G. Bibcode: 2011yCat..35360053C Altcode: 2011yCat..35369053C Photometry of HE 0435-1223, as in Fig. 3 of the paper. The first column gives the Julian date and corresponds to HJD days. Columns 2-9 give the photometric measurements of the quasar components A, B, C and D respectively, with the corresponding error bars. The last column provides the name of the telescope used for each measurement.

(1 data file). Title: Observations and Orbits of Comets Authors: Sanner, J.; Angelow, S.; Chaumont, F.; Heimann, L.; Lawida, M.; Pollitt, A.; Proels, J.; Ronken, K.; Saenger, S.; Honkova, M.; Tichy, M.; Ticha, J.; Kocer, M.; Bacci, P.; Tesi, L.; Fagioli, G.; Tombelli, M.; Foglia, S.; Interrante, G.; Bartolini, S.; Casali, M.; Coffano, A.; Marinello, W.; Micheli, M.; Pizzetti, G.; Jaeger, M.; Prosperi, E.; Vollmann, W.; Buzzi, L.; Naves, R.; Campas, M.; Donati, S.; Scotti, J. V.; Kadota, K.; Abe, H.; Seki, T.; Shimomoto, S.; Sato, H.; Wakuda, S.; Jung, M.; Bill, H.; Kashuba, S.; Kashuba, V.; Gorbanev, Y.; Podlesnyak, S.; Stogneeva, I.; Bressi, T. H.; Gibbs, A. R.; Kowalski, R. A.; Hill, R. E.; Ahern, J. D.; Beshore, E. C.; Boattini, A.; Garradd, G. J.; Tricarico, P.; Grauer, A. D.; Larson, S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.; Gall, C.; Moritz, N.; Elliott, R.; Castellano, J.; Vidal, J. R.; Dupouy, P.; Manzini, F.; Behrend, R.; Bernasconi, L.; Shurpakov, S.; Thinius, B.; Nevski, V.; Linder, J.; Nicolas, J.; Pivato, D.; Lopesino, J.; Overhaus, C.; Bosch, J. M.; Olivera, R. M.; Martignoni, M.; Haeusler, B.; Noel, T.; Bryssinck, E.; Sachot, G.; Soulier, J. F.; Diepvens, A.; Gerke, V.; Novichonok, A.; Plyachshenko, Y.; Grau Horta, F.; Magrin, E.; Gonano, V.; Andrea, M.; Zhao, H. B.; Yao, J. S.; Zhaori, G. T.; Lu, H.; Wang, M.; Hong, R. Q.; Hu, L. F.; Xia, Y.; Sugiyama, Y.; Hills, K.; Takahashi, T.; Herald, D.; Guido, E.; Howes, N.; Sostero, G.; Lister, T.; Camilleri, P.; Drummond, J.; Primak, N.; Schultz, A.; Watters, S.; Thiel, J.; Goggia, T.; Elenin, L.; Molotov, I.; Haugh, T.; Bell, C.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Losse, F.; Limon, F.; Gonzalez, J.; Garcia, F.; Canales, O.; Fletcher, J.; Ruiz, J.; Curto Amigo, J.; Williams, G. V. Bibcode: 2011MPEC....U...42S Altcode: No abstract at ADS Title: Minor Planet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2011MPC..76020...7J Altcode: No abstract at ADS Title: WASP-50 b: a hot Jupiter transiting a moderately active solar-type star Authors: Gillon, M.; Doyle, A. P.; Lendl, M.; Maxted, P. F. L.; Triaud, A. H. M. J.; Anderson, D. R.; Barros, S. C. C.; Bento, J.; Collier-Cameron, A.; Enoch, B.; Faedi, F.; Hellier, C.; Jehin, E.; Magain, P.; Montalbán, J.; Pepe, F.; Pollacco, D.; Queloz, D.; Smalley, B.; Segransan, D.; Smith, A. M. S.; Southworth, J.; Udry, S.; West, R. G.; Wheatley, P. J. Bibcode: 2011A&A...533A..88G Altcode: 2011arXiv1108.2641G We report the discovery by the WASP transit survey of a giant planet in a close orbit (0.0295 ± 0.0009 AU) around a moderately bright (V = 11.6, K = 10) G9 dwarf (0.89 ± 0.08 M⊙, 0.84 ± 0.03 R⊙) in the Southern constellation Eridanus. Thanks to high-precision follow-up photometry and spectroscopy obtained by the telescopes TRAPPIST and Euler, the mass and size of this planet, WASP-50 b, are well constrained to 1.47 ± 0.09 MJup and 1.15 ± 0.05 RJup, respectively. The transit ephemeris is 2 455 558.6120 (±0.0002) + N × 1.955096 (±0.000005) HJDUTC. The size of the planet is consistent with basic models of irradiated giant planets. The chromospheric activity (log R'HK = -4.67) and rotational period (Prot = 16.3 ± 0.5 days) of the host star suggest an age of 0.8 ± 0.4 Gy that is discrepant with a stellar-evolution estimate based on the measured stellar parameters (ρ∗ = 1.48 ± 0.10 ρ⊙, Teff = 5400 ± 100 K, [Fe/H] = -0.12 ± 0.08) which favors an age of 7 ± 3.5 Gy. This discrepancy could be explained by the tidal and magnetic influence of the planet on the star, in good agreement with the observations that stars hosting hot Jupiters tend to show faster rotation and magnetic activity. We measure a stellar inclination of 84-31+6 deg, disfavoring a high stellar obliquity. Thanks to its large irradiation and the relatively small size of its host star, WASP-50 b is a good target for occultation spectrophotometry, making it able to constrain the relationship between hot Jupiters' atmospheric thermal profiles and the chromospheric activity of their host stars.

The photometric time-series used in this work are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/533/A88 Title: TRAPPIST: TRAnsiting Planets and PlanetesImals Small Telescope Authors: Jehin, E.; Gillon, M.; Queloz, D.; Magain, P.; Manfroid, J.; Chantry, V.; Lendl, M.; Hutsemékers, D.; Udry, S. Bibcode: 2011Msngr.145....2J Altcode: TRAPPIST is a 60-cm robotic telescope that was installed in April 2010 at the ESO La Silla Observatory. The project is led by the Astrophysics and Image Processing group (AIP) at the Department of Astrophysics, Geophysics and Oceanography (AGO) of the University of Liège, in close collaboration with the Geneva Observatory, and has been funded by the Belgian Fund for Scientific Research (F.R.S.-FNRS) and the Swiss National Science Foundation (SNF). It is devoted to the detection and characterisation of exoplanets and to the study of comets and other small bodies in the Solar System. We describe here the goals of the project and the hardware and present some results obtained during the first six months of operation. Title: Observations and Orbits of Comets Authors: Tesi, L.; Bacci, P.; Fagioli, G.; Tombelli, M.; Foglia, S.; Galli, F.; Bartolini, S.; Cernis, K.; Zdanavicius, J.; Jaeger, M.; Prosperi, E.; Vollmann, W.; Galli, G.; Buzzi, L.; Naves, R.; Campas, M.; Kadota, K.; Abe, H.; Baransky, A.; Aleksakhina, E.; Ikari, Y.; Vidal, J. R.; Kocher, P.; Rinner, C.; Kugel, F.; Reszelski, M.; Nevski, V.; Linder, J.; Nicolas, J.; Pivato, D.; Haeusler, B.; Bryssinck, E.; Plaksa, S.; Sachot, G.; Soulier, J. F.; Diepvens, A.; Lindner, P.; Dangl, G.; Hills, K.; Herald, D.; McNaught, R. H.; Ahern, J. D.; Beshore, E. C.; Boattini, A.; Garradd, G. J.; Gibbs, A. R.; Grauer, A. D.; Hill, R. E.; Kowalski, R. A.; Larson, S. M.; Camilleri, P.; McCormick, J.; Drummond, J.; Primak, N.; Schultz, A.; Watters, S.; Thiel, J.; Goggia, T.; Boaz, R. Z.; Howes, N.; Blyth, H.; Sostero, G.; Guido, E.; Sato, H.; Elenin, L.; Holmes, R.; Vorobjov, T.; Haugh, T.; Bell, C.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Sparrenberger, M.; Ruiz, J. M.; Baez, J.; Lozano, I.; Cardenete, S.; Chinchilla, J.; Garri, M.; Limon, F.; Gonzalez, J.; Garcia, F.; Muler, G.; Vazquez Lopez, G.; Henriquez, J. A.; Canales, O.; Benavides, R.; Temprano, J.; Fletcher, J.; Williams, G. V. Bibcode: 2011MPEC....P...23T Altcode: No abstract at ADS Title: VizieR Online Data Catalog: WASP-50b photometry and radial velocities (Gillon+, 2011) Authors: Gillon, M.; Doyle, A. P.; Lendl, M.; Maxted, P. F. L.; Triaud, A. H. M. J.; Anderson, D. R.; Barros, S. C. C.; Bento, J.; Collier-Cameron, A.; Enoch, B.; Faedi, F.; Hellier, C.; Jehin, E.; Magain, P.; Montalban, J.; Pepe, F.; Pollacco, D.; Queloz, D.; Smalley, B.; Segransan, D.; Smith, A. M. S.; Southworth, J.; Udry, S.; West, R. G.; Wheatley, P. J. Bibcode: 2011yCat..35330088G Altcode: 2011yCat..35339088G Files wasp.dat, trappist.dat and euler.dat contain the photometric time-series presented in the paper and obtained by the WASP transit survey, and by the TRAPPIST and Euler telescopes.

(4 data files). Title: Minor Planet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2011MPC..75700...7J Altcode: No abstract at ADS Title: Comet 45P/HONDA-MRKOS-PAJDUSAKOVA Authors: McNaught, R. H.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Williams, G. V. Bibcode: 2011MPEC....P...11M Altcode: No abstract at ADS Title: Comet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2011MPC..75563...4J Altcode: No abstract at ADS Title: Minor Planet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2011MPC..75510..12J Altcode: No abstract at ADS Title: Observations and Orbits of Comets Authors: Tesi, L.; Bacci, P.; Fagioli, G.; Bacci, R.; Casali, M.; Coffano, A.; Marinello, W.; Micheli, M.; Pizzetti, G.; Cernis, K.; Zdanavicius, J.; Maskoliunas, M.; Haver, R.; Foglia, S.; Galli, G.; Buzzi, L.; Naves, R.; Campas, M.; Hasubick, W.; Donati, S.; McAndrew, S. G.; Sanchez C., A.; Donato, L.; Gonano, V.; Travagini, M.; Bill, H.; Baransky, A.; Buriev, A.; Ponomarenko, V.; Scotti, J. V.; Kowalski, R. A.; Ahern, J. D.; Beshore, E. C.; Boattini, A.; Garradd, G. J.; Gibbs, A. R.; Tricarico, P.; Grauer, A. D.; Hill, R. E.; Larson, S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.; Brewington, H.; Dembicky, J.; Harvanek, M.; Ketzeback, B.; Long, D.; Pan, K.; Malanushenko, O.; McMillan, R.; Snedden, S.; Watters, S.; Sarneczky, K.; Durig, D. T.; Uriostegui, J. R.; Danusantoso, J. F.; Kharel, S.; Duenas, D. E.; Rice, A. C.; Vasquez, J. A.; Murphree, C. L.; Koury, E. S.; Castellano, J.; Ferrando, R.; Vidal, J. R.; Baldris, F.; Kocher, P.; Jaeger, M.; Prosperi, E.; Vollmann, W.; Rinner, C.; Kugel, F.; Nicolas, J.; Bel, J.; Borghini, W.; Bryssinck, E.; Sachot, G.; Soulier, J. F.; Diepvens, A.; Dangl, G.; Hills, K.; Takahashi, T.; Novichonok, A.; Baroni, S.; Concari, P.; Tombelli, M.; Chestnov, D.; Sato, H.; Herald, D.; Lister, T.; Guido, E.; Howes, N.; Sostero, G.; McCormick, J.; Primak, N.; Schultz, A.; Thiel, J.; Goggia, T.; Glinos, T.; Plaksa, S.; Elenin, L.; Hall-Angel Peaks Observatory, J.; Hall, J.; Holmes, R.; Vorobjov, T.; Linder, T.; Mills, M.; Hug, G.; Sherrod, P. C.; Bell, C.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Limon, F.; Gonzalez, J.; Pena Ciriza, F.; Del Maes, A.; Hernandez, J. F.; Garcia, F.; Fletcher, J.; Climent, T.; Williams, G. V. Bibcode: 2011MPEC....N...13T Altcode: No abstract at ADS Title: Comet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2011MPC..75359..19J Altcode: No abstract at ADS Title: Observations and Orbits of Comets Authors: Naves, R.; Campas, M.; Seki, T.; Shimomoto, S.; Sato, H.; Donato, L.; Gonano, V.; Travagini, M.; Baransky, A.; Buriev, A.; Ponomarenko, V.; Beshore, E.; Ahern, J. D.; Boattini, A.; Garradd, G. J.; Gibbs, A. R.; Tricarico, P.; Grauer, A. D.; Hill, R. E.; Kowalski, R. A.; Larson, S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.; Schwartz, M.; Holvorcem, P. R.; Jaeger, M.; Prosperi, E.; Vollmann, W.; Rinner, C.; Kugel, F.; Camarasa, J.; Bryssinck, E.; Sachot, G.; Diepvens, A.; Hills, K.; Takahashi, T.; Baroni, S.; Buzzi, L.; Concari, P.; Foglia, S.; Galli, G.; Tombelli, M.; Camilleri, P.; Primak, N.; Schultz, A.; Watters, S.; Thiel, J.; Goggia, T.; Glinos, T.; Guido, E.; Sostero, G.; Bell, C.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Williams, G. V. Bibcode: 2011MPEC....M...11N Altcode: No abstract at ADS Title: EPOXI: Comet 103P/Hartley 2 Observations from a Worldwide Campaign Authors: Meech, K. J.; A'Hearn, M. F.; Adams, J. A.; Bacci, P.; Bai, J.; Barrera, L.; Battelino, M.; Bauer, J. M.; Becklin, E.; Bhatt, B.; Biver, N.; Bockelée-Morvan, D.; Bodewits, D.; Böhnhardt, H.; Boissier, J.; Bonev, B. P.; Borghini, W.; Brucato, J. R.; Bryssinck, E.; Buie, M. W.; Canovas, H.; Castellano, D.; Charnley, S. B.; Chen, W. P.; Chiang, P.; Choi, Y. -J.; Christian, D. J.; Chuang, Y. -L.; Cochran, A. L.; Colom, P.; Combi, M. R.; Coulson, I. M.; Crovisier, J.; Dello Russo, N.; Dennerl, K.; DeWahl, K.; DiSanti, M. A.; Facchini, M.; Farnham, T. L.; Fernández, Y.; Florén, H. G.; Frisk, U.; Fujiyoshi, T.; Furusho, R.; Fuse, T.; Galli, G.; García-Hernández, D. A.; Gersch, A.; Getu, Z.; Gibb, E. L.; Gillon, M.; Guido, E.; Guillermo, R. A.; Hadamcik, E.; Hainaut, O.; Hammel, H. B.; Harker, D. E.; Harmon, J. K.; Harris, W. M.; Hartogh, P.; Hashimoto, M.; Häusler, B.; Herter, T.; Hjalmarson, A.; Holland, S. T.; Honda, M.; Hosseini, S.; Howell, E. S.; Howes, N.; Hsieh, H. H.; Hsiao, H. -Y.; Hutsemékers, D.; Immler, S. M.; Jackson, W. M.; Jeffers, S. V.; Jehin, E.; Jones, T. J.; de Juan Ovelar, M.; Kaluna, H. M.; Karlsson, T.; Kawakita, H.; Keane, J. V.; Keller, L. D.; Kelley, M. S.; Kinoshita, D.; Kiselev, N. N.; Kleyna, J.; Knight, M. M.; Kobayashi, H.; Kobulnicky, H. A.; Kolokolova, L.; Kreiny, M.; Kuan, Y. -J.; Küppers, M.; Lacruz, J. M.; Landsman, W. B.; Lara, L. M.; Lecacheux, A.; Levasseur-Regourd, A. C.; Li, B.; Licandro, J.; Ligustri, R.; Lin, Z. -Y.; Lippi, M.; Lis, D. C.; Lisse, C. M.; Lovell, A. J.; Lowry, S. C.; Lu, H.; Lundin, S.; Magee-Sauer, K.; Magain, P.; Manfroid, J.; Mazzotta Epifani, E.; McKay, A.; Melita, M. D.; Mikuz, H.; Milam, S. N.; Milani, G.; Min, M.; Moreno, R.; Mueller, B. E. A.; Mumma, M. J.; Nicolini, M.; Nolan, M. C.; Nordh, H. L.; Nowajewski, P. B.; Odin Team; Ootsubo, T.; Paganini, L.; Perrella, C.; Pittichová, J.; Prosperi, E.; Radeva, Y. L.; Reach, W. T.; Remijan, A. J.; Rengel, M.; Riesen, T. E.; Rodenhuis, M.; Rodríguez, D. P.; Russell, R. W.; Sahu, D. K.; Samarasinha, N. H.; Sánchez Caso, A.; Sandqvist, A.; Sarid, G.; Sato, M.; Schleicher, D. G.; Schwieterman, E. W.; Sen, A. K.; Shenoy, D.; Shi, J. -C.; Shinnaka, Y.; Skvarc, J.; Snodgrass, C.; Sitko, M. L.; Sonnett, S.; Sosseini, S.; Sostero, G.; Sugita, S.; Swinyard, B. M.; Szutowicz, S.; Takato, N.; Tanga, P.; Taylor, P. A.; Tozzi, G. -P.; Trabatti, R.; Trigo-Rodríguez, J. M.; Tubiana, C.; de Val-Borro, M.; Vacca, W.; Vandenbussche, B.; Vaubaillion, J.; Velichko, F. P.; Velichko, S. F.; Vervack, R. J., Jr.; Vidal-Nunez, M. J.; Villanueva, G. L.; Vinante, C.; Vincent, J. -B.; Wang, M.; Wasserman, L. H.; Watanabe, J.; Weaver, H. A.; Weissman, P. R.; Wolk, S.; Wooden, D. H.; Woodward, C. E.; Yamaguchi, M.; Yamashita, T.; Yanamandra-Fischer, P. A.; Yang, B.; Yao, J. -S.; Yeomans, D. K.; Zenn, T.; Zhao, H.; Ziffer, J. E. Bibcode: 2011ApJ...734L...1M Altcode: 2011arXiv1106.0367K Earth- and space-based observations provide synergistic information for space mission encounters by providing data over longer timescales, at different wavelengths and using techniques that are impossible with an in situ flyby. We report here such observations in support of the EPOXI spacecraft flyby of comet 103P/Hartley 2. The nucleus is small and dark, and exhibited a very rapidly changing rotation period. Prior to the onset of activity, the period was ~16.4 hr. Starting in 2010 August the period changed from 16.6 hr to near 19 hr in December. With respect to dust composition, most volatiles and carbon and nitrogen isotope ratios, the comet is similar to other Jupiter-family comets. What is unusual is the dominance of CO2-driven activity near perihelion, which likely persists out to aphelion. Near perihelion the comet nucleus was surrounded by a large halo of water-ice grains that contributed significantly to the total water production. Title: Minor Planet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2011MPC..75288...5J Altcode: No abstract at ADS Title: Observations and Orbits of Comets Authors: Eglitis, I.; Cernis, K.; Tesi, L.; Bacci, P.; Fagioli, G.; Caronia, A.; Buzzi, L.; Urakawa, S.; Hashimoto, N.; Asami, A.; Nishiyama, K.; Okumura, S.; Sakamoto, T.; Kadota, K.; Abe, H.; Seki, T.; Shimomoto, S.; Sato, H.; Endate, K.; Sarneczky, K.; Donato, L.; Gonano, V.; Travagini, M.; Bill, H.; Kashuba, S.; Kashuba, V.; Gorbanev, Y.; Podlesnyak, S.; Stogneeva, I.; Baransky, A.; Buriev, A.; Ponomarenko, V.; Zhdanov, A.; Butygina, O.; Weissman, P. R.; Brozovic, M.; Owen, W. M., Jr.; Bressi, T. H.; Hergenrother, C. W.; Grauer, A. D.; Gibbs, A. R.; Kowalski, R. A.; Beshore, E.; Ahern, J. D.; Boattini, A.; Garradd, G. J.; Tricarico, P.; Hill, R. E.; Larson, S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.; Mackintosh, R.; Konishi, M.; Salvo, R.; Bruzzone, S.; Roland, S.; Tancredi, G.; Martinez, M.; Abe, S.; Guo, J. K.; Chen, W. P.; Schwartz, M.; Holvorcem, P. R.; Castellano, J.; Vidal, J. R.; Dupouy, P.; Baldris, F.; Jaeger, M.; Prosperi, E.; Prosperi, S.; Vollmann, W.; Rinner, C.; Kugel, F.; Bryssinck, E.; Soulier, J. F.; Diepvens, A.; Zilch, T.; Hills, K.; Takahashi, T.; Baroni, S.; Concari, P.; Foglia, S.; Galli, G.; Tombelli, M.; Camilleri, P.; Linder, J.; Herald, D.; Miles, R.; Primak, N.; Schultz, A.; Watters, S.; Thiel, J.; Goggia, T.; Micheli, M.; Dymock, R.; Masek, M.; Chestnov, D.; Novichonok, A.; Plaksa, S.; Elenin, L.; Holmes, R.; Vorobjov, T.; Sherrod, P. C.; Bell, C.; Colazo, C.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Gonzalez, J.; Hernandez, J. F.; Garcia, F.; Lacruz, J.; Williams, G. V. Bibcode: 2011MPEC....L...51E Altcode: No abstract at ADS Title: Comet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2011MPC..75109..50J Altcode: No abstract at ADS Title: Comet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2011MPC..74775..38J Altcode: No abstract at ADS Title: Observations and Orbits of Comets Authors: Tesi, L.; Bacci, P.; Fagioli, G.; Vivarelli, M.; Greco, L.; Casali, M.; Coffano, A.; Marinello, W.; Micheli, M.; Pizzetti, G.; Apitzsch, R.; Naves, R.; Campas, M.; Hasubick, W.; Seki, T.; Shimomoto, S.; Sato, H.; Christie, G. W.; Natusch, T.; Donato, L.; Gonano, V.; Travagini, M.; Bill, H.; Baransky, A.; Bambery, R.; Helin, E.; Pravdo, S.; Hicks, M.; Lawrence, K.; Kervin, P.; Matson, R.; Grauer, A. D.; Gibbs, A. R.; Ahern, J. D.; Beshore, E. C.; Boattini, A.; Garradd, G. J.; Tricarico, P.; Hill, R. E.; Kowalski, R. A.; Larson, S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.; Castellano, J.; Ferrando, R.; Vidal, J. R.; Dupouy, P.; Baldris, F.; Muller, J. J.; Cozzi, E.; Jaeger, M.; Prosperi, E.; Vollmann, W.; Rinner, C.; Kugel, F.; Franco, L.; Camarasa, J.; Nicolas, J.; Bosch, J. M.; Soulier, J. F.; Diepvens, A.; Ohshima, Y.; Takahashi, T.; Camilleri, P.; Sostero, G.; Guido, E.; Bryssinck, E.; Chestnov, D.; Novichonok, A.; Plaksa, S.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Buczynski, D.; Fraga, A.; Losse, F.; Pena Ciriza, F.; Del Maes, A.; Muler, G.; Ruiz, J. M.; Williams, G. V. Bibcode: 2011MPEC....J...52T Altcode: No abstract at ADS Title: Minor Planet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Levesque, M.; Christiaens, V. Bibcode: 2011MPC..75004..11J Altcode: No abstract at ADS Title: Observations and Orbits of Comets Authors: Tesi, L.; Bacci, P.; Garozzo, M.; Mikuz, B.; Mikuz, H.; Knoefel, A.; Lehmann, G.; Vilagi, J.; Kornos, L.; Haver, R.; Jaeger, M.; Prosperi, E.; Vollmann, W.; Buzzi, L.; Naves, R.; Campas, M.; Hasubick, W.; Donati, S.; Ligustri, R.; Brunato, P.; Kadota, K.; Abe, H.; Seki, T.; Shimomoto, S.; Sato, H.; Endate, K.; Sanchez, A.; Kuli, Z.; Sarneczky, K.; Christie, G. W.; Natusch, T.; Bill, H.; Quadri, U.; Strabla, L.; Girelli, R.; Kashuba, S.; Gorbanev, Y.; Podlesnyak, S.; Stogneeva, I.; Baransky, A.; Zhdanov, A.; Vorontseva, A.; Markov, Y.; Bressi, T. H.; Scotti, J. V.; Grauer, A. D.; Boattini, A.; Tricarico, P.; Kowalski, R. A.; Hill, R. E.; Ahern, J. D.; Beshore, E. C.; Garradd, G. J.; Gibbs, A. R.; Tric, P.; Larson, S. M.; McNaught, R. H.; Tricario, P.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.; Durig, D. T.; Caine, C. S.; Green, J. P.; Best, H. L.; Hamilton, I. G.; Liu, H.; Skidmore, L. M.; Stinson, J. W.; Cowan, W. M.; Ikari, Y.; Castellano, J.; Dymock, R.; Vidal, J. R.; Dupouy, P.; Storey, D.; Mueller, J. J.; Cozzi, E.; Rinner, C.; Kugel, F.; Franco, L.; Shurpakov, S.; Pietschnig, M.; Aymami, J. M.; Nevski, V.; Linder, J.; Bel, J.; Overhaus, C.; Bosch, J. M.; Haeusler, B.; Noel, T.; Bryssinck, E.; Sachot, G.; Soulier, J. F.; Diepvens, A.; Zilch, T.; Gao, X.; Hui, M. -T.; Plyachshenko, Y.; Curtis, I.; Hills, K.; Takahashi, T.; Camilleri, P.; Chestnov, D.; Novichonok, A.; Plaksa, S.; Baroni, S.; Concari, P.; Foglia, S.; Galli, G.; Tombelli, M.; Sostero, G.; Guido, E.; Kiely, W.; Herald, D.; McCormick, J.; Primak, N.; Schultz, A.; Watters, S.; Thiel, J.; Goggia, T.; Hergenrother, C. W.; Elenin, L.; Holmes, R.; Vorobjov, T.; Haugh, T.; Sherrod, P. C.; Bell, C.; Tifner, F.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Eugenio Tapia Ayuga, C.; Losse, F.; Limon, F.; Gonzalez, J.; Martin, J. J.; Garcia, F.; Muler, G.; Ruiz, J. M.; Canales, O.; Temprano, J.; Lacruz, J.; Fletcher, J.; Williams, G. V. Bibcode: 2011MPEC....G...58T Altcode: No abstract at ADS Title: Minor Planet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Christiaens, V. Bibcode: 2011MPC..74632...9J Altcode: No abstract at ADS Title: Comet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2011MPC..74333..40J Altcode: No abstract at ADS Title: Observations and Orbits of Comets Authors: Tombelli, M.; Foglia, S.; Interrante, G.; Masotti, E.; Castro, L.; Casali, M.; Marinello, W.; Micheli, M.; Pizzetti, G.; Soffiantini, A.; Buzzi, L.; Almendros, I.; Naves, R.; Campas, M.; Reina, E.; Ligustri, R.; Brunato, P.; Turchetti, R.; Benvenuti, M.; Scotti, J. V.; Asami, A.; Hashimoto, N.; Nishiyama, K.; Okumura, S.; Sakamoto, T.; Urakawa, S.; Abe, H.; Seki, T.; Shimomoto, S.; Sato, H.; Endate, K.; McAndrew, S. G.; Donato, L.; Gonano, V.; Travagini, M.; Kelemen, J.; Baransky, A.; Zhdanov, A.; Pasichnyk, P.; Ponomarenko, V.; Vorontseva, A.; Markov, Y.; Barinova, K.; Tarasenko, Y.; Hill, R. E.; Ahern, J. D.; Beshore, E. C.; Boattini, A.; Garradd, G. J.; Gibbs, A. R.; Tricarico, P.; Grauer, A. D.; Kowalski, R. A.; Larson, S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.; Mackintosh, R.; Konishi, M.; Durig, D. T.; Green, J. P.; Maxey, S. H.; Patton, J. E.; Stevens, D. S.; Singer, J. T.; Skidmore, L. M.; Morgan, W. R.; Vines, L. F.; Castellano, J.; Ferrando, R.; Ferrando, M.; Vidal, J. R.; Dupouy, P.; Mueller, J. J.; Jaeger, M.; Prosperi, E.; Prosperi, S.; Vollmann, W.; Rinner, C.; Kugel, F.; Nevski, V.; Haeusler, B.; Bryssinck, E.; Soulier, J. F.; Diepvens, A.; Shurpakov, S.; Hui, M. -T.; Sugiyama, Y.; Camilleri, P.; Plaksa, S.; Primak, N.; Schultz, A.; Watters, S.; Thiel, J.; Goggia, T.; Chestnov, D.; Novichonok, A.; Elenin, L.; Molotov, I.; Sherrod, P. C.; Bell, C.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Gonzalez, J.; Garcia, R.; Pena Ciriza, F.; Del Maes, A.; Baez, J.; Garcia, F.; Muler, G.; Ruiz, J. M.; Henriquez, J. A.; Canales, O.; Curto, J.; Temprano, J.; Pascual, J. I.; Williams, G. V. Bibcode: 2011MPEC....G...90T Altcode: No abstract at ADS Title: Comet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2011MPC..73990..25J Altcode: No abstract at ADS Title: Minor Planet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2011MPC..74232...7J Altcode: No abstract at ADS Title: TRAPPIST: a robotic telescope dedicated to the study of planetary systems Authors: Gillon, M.; Jehin, E.; Magain, P.; Chantry, V.; Hutsemékers, D.; Manfroid, J.; Queloz, D.; Udry, S. Bibcode: 2011EPJWC..1106002G Altcode: 2011arXiv1101.5807G We present here a new robotic telescope called TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope). Equipped with a high-quality CCD camera mounted on a 0.6 meter light weight optical tube, TRAPPIST has been installed in April 2010 at the ESO La Silla Observatory (Chile), and is now beginning its scientific program. The science goal of TRAPPIST is the study of planetary systems through two approaches: the detection and study of exoplanets, and the study of comets. We describe here the objectives of the project, the hardware, and we present some of the first results obtained during the commissioning phase. Title: Observations and Orbits of Comets Authors: Gajdos, S.; Vilagi, J.; Apitzsch, R.; Buzzi, L.; Ligustri, R.; Kadota, K.; Asami, A.; Seki, T.; Muraoka, K.; Shimomoto, S.; Donato, L.; Gonano, V.; Jung, M.; Bill, H.; Kelemen, J.; Kashuba, S.; Kashuba, V.; Gorbanev, Y.; Podlesnyak, S.; Stogneeva, I.; Baransky, A.; Ponomarenko, V.; Simon, A.; Boattini, A.; Ahern, J. D.; Beshore, E. C.; Garradd, G. J.; Gibbs, A. R.; Grauer, A. D.; Hill, R. E.; Kowalski, R. A.; Larson, S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.; Ikari, Y.; Castellano, J.; Kocher, P.; Rinner, C.; Kugel, F.; Bacci, P.; Enzo, R.; Emilio, R.; Martignoni, M.; Bryssinck, E.; Soulier, J.; Curtis, I.; Hills, K.; Takahashi, T.; Camilleri, P.; Sato, H.; Herald, D.; Drummond, J.; Dymock, R.; Chestnov, D.; Novichonok, A.; Linder, J.; Baroni, S.; Concari, P.; Foglia, S.; Galli, G.; Tombelli, M.; Elenin, L.; Molotov, I.; Bell, C.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Carreno, A.; Piqueras, J.; Hernandez, J. F.; Garcia, F.; Muler, G.; Ruiz, J. M.; Williams, G. V. Bibcode: 2011MPEC....D...36G Altcode: No abstract at ADS Title: Comet Observations [I40 La Silla--TRAPPIST] Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2011MPC..73618..49J Altcode: No abstract at ADS Title: Comet P/2005 l1 (mcnaught) Authors: Honkova, M.; Tichy, M.; Ticha, J.; Kocer, M.; Bilkina, B.; Tesi, L.; Fagioli, G.; Bacci, P.; Mikuz, H.; Gajdos, S.; Vilagi, J.; Casali, M.; Marinello, W.; Micheli, M.; Pizzetti, G.; Soffiantini, A.; Galli, G.; Buzzi, L.; Almendros, I.; Naves, R.; Campas, M.; Hasubick, W.; Scotti, J. V.; Asami, A.; Nishiyama, K.; Kadota, K.; Abe, H.; Seki, T.; Shimomoto, S.; Sato, H.; Muraoka, K.; Wakuda, S.; Kuli, Z.; Sarneczky, K.; Donato, L.; Gonano, V.; Muschallik, I.; Peters, J. P.; Bill, H.; Elliott, G. T.; Tholen, D. J.; Pittichova, J.; Kleyna, J.; Ishiguro, M.; Baransky, A.; Baransky, B.; Baranska, O.; Grauer, A. D.; Kowalski, R. A.; Boattini, A.; Hill, R. E.; Ahern, J. D.; Beshore, E. C.; Garradd, G. J.; Gibbs, A. R.; Larson, S. M.; McNaught, R. H.; Blythe, M.; Spitz, G.; Brungard, R.; Paige, J.; Festler, P.; McVey, T.; Valdivia, A.; Durig, D. T.; Murphree, V. J.; Wetherbee, R. M.; Liu, H.; Caine, C. S.; Hamilton, I. G.; Ikari, Y.; Le Corre, L.; Reddy, V.; Dyvig, R.; Castellano, J.; Vidal, J. R.; Dupouy, P.; Baldris, F.; Cortes, E.; Jaeger, M.; Prosperi, E.; Prosperi, S.; Vollmann, W.; Rinner, C.; Kugel, F.; Trigo-Rodriguez, J. M.; Camarasa, J.; Bel, J.; Lopesino, J.; Borghini, W.; Bosch, J. M.; Martignoni, M.; Haeusler, B.; Noel, T.; Bryssinck, E.; Bros, X.; Sachot, G.; Soulier, J.; Rhemann, G.; Chestnov, D.; Matkin, A.; de Groote, B.; Diepvens, A.; Xu, Z.; Gao, X.; Ohshima, Y.; Sugiyama, Y.; Hills, K.; Takahashi, T.; Shurpakov, S.; Linder, J.; Sostero, G.; Guido, E.; Novichonok, A.; McCusker, C.; McInteggart, H.; Adams, J.; Camilleri, P.; Dymock, R.; Glinos, T.; Ryan, W. H.; Ryan, E. V.; Ligustri, R.; Plaksa, S.; Baroni, S.; Concari, P.; Foglia, S.; Tombelli, M.; Karge, S.; Elenin, L.; Molotov, I.; Sherrod, P. C.; Bell, C.; Renzi, M.; Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.; Limon, F.; Gonzalez, J.; Carreno, A.; Piqueras, J.; Hernandez, J. F.; Martin, J. J.; Baez, J.; Garcia, F.; Ruiz, J. M.; Muler, G.; Benavides, R.; Curto, J.; Temprano, J.; Pascual, J. I.; Climent, T.; Williams, G. V. Bibcode: 2011MPEC....D...06H Altcode: No abstract at ADS Title: (596) Scheila Authors: Jehin, E.; Manfroid, J.; Hutsemekers, D.; Gillon, M.; Magain, P. Bibcode: 2011CBET.2632....2J Altcode: E. Jehin, J. Manfroid, D. Hutsemekers, M. Gillon, and P. Magain, Fonds National de la Recherche Scientifique, Liege University, report on broad- and narrow-band imaging of the (596) Scheila outburst (CBET 2583) with the TRAPPIST 0.60-m telescope at La Silla, and on optical spectroscopy with the European Southern Observatory's Very Large Telescope (VLT) at Paranal. R-band imaging from 2010 Dec. 12.3 to 21.3 UT revealed two arc-like coma features expanding at a regular pace. The first such feature was 1' long on 2010 Dec. 12, oriented to the northeast and bending to p.a. 280 deg (the anti-solar direction). The second feature was shorter, 30" on Dec. 12, oriented to the south and bending to p.a. 230 deg. Both features were getting larger and fainter with time (4' and 2' long, respectively, on Dec. 21.3). A narrow 45"-long tail, opposite the sun (p.a. 280 deg), was also observed in good seeing. R-band images taken on 2011 Jan. 4.3 and 5.3 after the full moon allowed Jehin et al. to again observe these features, seen as 7' and 4' long, respectively -- and much fainter. This discards any sustained activity of the minor planet. Narrow-band images obtained on 2010 Dec. 12.3 with cometary filters do not show any contribution from gases. A 20-min optical spectrum was obtained with FORS2 at the VLT on Dec. 13.3; it does not show any extended cometary gaseous emissions, but only a spatially extended continuum due to dust-scattered sunlight. Short B, V, R, and I exposures performed nearly every two nights from 2010 Dec. 12.3 to 2011 Jan. 5.3 give a magnitude for the nuclear condensation of V = 14.2 +/- 0.1 over the whole period, in agreement with the "APmag" value reported in the Jet Propulsion Laboratory ephemeris. No flux variation of the nuclear condensation was observed. Those preliminary results are in favor of a collisional scenario to explain the outburst of (596) Scheila, rather than a cometary driven activity. This case might be similar to the outburst of comet P/2010 A2, which may have resulted from an impact of a minor planet (Snodgrass 2010, Nature 467, 814). Title: Comet 103P/Hartley Authors: Jehin, E.; Manfroid, J.; Hutsemekers, D.; Gillon, M.; Magain, P. Bibcode: 2010CBET.2589....1J Altcode: E. Jehin, J. Manfroid, D. Hutsemekers, M. Gillon, and P. Magain, Liege University, report narrowband imaging of comet 103P using the TRAPPIST 0.60m telescope at the European Southern Observatory, La Silla. Three to four hours of observation were secured on 26 clear nights from Oct. 29 to Dec. 7, using six different cometary filters (Farnham et al. 2000, Icarus 147, 180). The flux of five gaseous species (CN, OH, H_2O+, C_2, C_3) and the dust continuum (via the C/1995 O1 green continuum filter, GC) was measured in a 26" aperture. Periodic variations of the gas species are observed, superimposed on the long-term trend, with CN showing the strongest variations (0.4-mag amplitude). The dust light curve is nearly flat. No gas or dust outburst has been detected during the above period of observation, although CN and OH show a slow flux increase with respect to other species during several days in early November. A period search with the first two weeks of data gave a smooth phase diagram for a period of 18.4 +/- 0.3 hours. These observations are in good agreement with the period reported from Arecibo radar observations of the nucleus (18.1 +/- 0.3 hours on Oct. 24-27; IAUC 9179). Including two more weeks of data, it became clear that the period was increasing. A change from about 18.2 to 19 hours was derived during the above observing window that might be related to a change of the rotation period of comet 103P of about 2 hours in 100 days. Such a rapid slowing down is in agreement with rotation values reported before perihelion (16.6 +/- 0.5 hr on Aug. 13-17; IAUC 9163). Title: Occultation by (136199) Eris Authors: Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P. Bibcode: 2010IAUC.9184....2J Altcode: 2010IAUC.9184B...2J E. Jehin, J. Manfroid, M. Gillon, D. Hutsemekers, and P. Magain report that they observed an occultation of a star of magnitude I about 15.2 by the dwarf planet Eris (then at V about 18.7) on Nov. 6 using the new telescope TRAPPIST at the European Southern Observatory (La Silla). A series of 3-s exposures of a field of size 3' x 3' (1".3/pixel) were secured in fast-readout mode (with a deadtime of 1.5 s), starting at 01h50m UT for one hour. Seven frames centered at 02h19m34s UT allowed them to derive the start of the occultation as 02h19m16s.75 +/- 0s.75 and the end as 02h19m47s.6 +/- 0s.2, for a total occultation time of 30.4 +/- 1.0 seconds. The predictions (see above) made by the Rio de Janeiro group (Assafin et al., Nov. 5) and by J. L. Ortiz estimated the time of the occultation around 02h18m UT for Chile, in good agreement with the observations. During the occultation, a point source is detected with a magnitude corresponding to that of Eris. A small flux increase was also seen at the middle of the occultation, which might result from refraction in Eris' atmosphere (Elliot and Olkin 1996, Ann. Rev. Earth Planet. Sci. 24, 89). Eris is by far the most-remote solar-system object observed to date via stellar occultation, with a geocentric distance of about 96 AU. TRAPPIST is a project driven by the University of Liege, in close collaboration with the Observatory of Geneva, supported by the Belgian Fund for Scientific Research and the Swiss National Science Foundation. Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses. VIII. Deconvolution of high resolution near-IR images and simple mass models for 7 gravitationally lensed quasars Authors: Chantry, V.; Sluse, D.; Magain, P. Bibcode: 2010A&A...522A..95C Altcode: 2010arXiv1007.3142C
Aims: We attempt to place very accurate positional constraints on seven gravitationally lensed quasars currently being monitored by the COSMOGRAIL collaboration, and shape parameters for the light distribution of the lensing galaxy. We attempt to determine simple mass models that reproduce the observed configuration and predict time delays. We finally test, for the quads, whether there is evidence of astrometric perturbations produced by substructures in the lensing galaxy, which may preclude a good fit with the simple models.
Methods: We apply the iterative MCS deconvolution method to near-IR HST archival data of seven gravitationally lensed quasars. This deconvolution method allows us to differentiate the contributions of the point sources from those of extended structures such as Einstein rings. This method leads to an accuracy of 1-2 mas in the relative positions of the sources and lens. The limiting factor of the method is the uncertainty in the instrumental geometric distortions. We then compute mass models of the lensing galaxy using state-of-the-art modeling techniques.
Results: We determine the relative positions of the lensed images and lens shape parameters of seven lensed quasars: HE 0047-1756, RX J1131-1231, SDSS J1138+0314, SDSS J1155+6346, SDSS J1226-0006, WFI J2026-4536, and HS 2209+1914. The lensed image positions are derived with 1-2 mas accuracy. Isothermal and de Vaucouleurs mass models are calculated for the whole sample. The effect of the lens environment on the lens mass models is taken into account with a shear term. Doubly imaged quasars are equally well fitted by each of these models. A large amount of shear is necessary to reproduce SDSS J1155+6346 and SDSS J1226-006. In the latter case, we identify a nearby galaxy as the dominant source of shear. The quadruply imaged quasar SDSS J1138+0314 is reproduced well by simple lens models, which is not the case for the two other quads, RX J1131-1231 and WFI J2026-4536. This might be the signature of astrometric perturbations caused by massive substructures in the galaxy, which are unaccounted for by the models. Other possible explanations are also presented.

Based on observations made with the NASA/ESA HST Hubble Space Telescope, obtained from the data archive at the Space Science Institute, which is operated by AURA, the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS-5-26555. Title: The 3/4 July 2010 Pluto Stellar-Occultation Observations Authors: Pasachoff, Jay M.; Elliot, J. L.; Souza, S. P.; Person, M. J.; Zuluaga, C.; Bosh, A. S.; Zangari, A. M.; Jensen-Clem, R.; Lockhart, M.; Gulbis, A. A. S.; Rojo, P.; Lu, M.; Malamut, C.; Levine, S. E.; Ivarsen, K. M.; Reichart, D. E.; LaCluyze, A. P.; Nysewander, M. C.; Haislip, J. B.; MacDonald, R. K. D.; Bailyn, C. D.; Emilio, M.; Jehin, E.; Gillon, M.; Manfroid, J.; Chantry, V.; Magain, P.; Hutsemekers, D.; Queloz, D. Bibcode: 2010DPS....42.2002P Altcode: 2010BAAS...42Q.983P Continuing our monitoring of Pluto's atmospheric temperature and pressure, previously shown by us to be increasing (Elliot et al., Nature 424, 165, 2003; Pasachoff et al., AJ 129, 1718, 2005) and subsequently found by us to be leveling off (Elliot et al., AJ 134, 1, 2007), we report on a stellar occultation by Pluto of UCAC2 mag=15.3, observed from South America and Africa on 4 July 2010 UT. Success was achieved with a 0.45 m at Cerro Calan using one of our POETS (Portable Occultation, Eclipse, and Transit System; Souza et al. PASP 118, 1550, 2006), a 1.0 SMARTS (Small and Medium Aperture Research Telescope System) at Cerro Tololo, four 0.6 m telescopes of PROMPT (Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes) on Cerro Tololo, and TRAPPIST's (TRansiting Planets and Planetesimals Small Telescope) 0.6-m telescope on La Silla in Chile; the 0.35 m telescope of U. Ponta Grossa, Brazil; and the 0.75-m ATOM (Automatic Telescope for Optical Monitoring), Namibia, using POETS. Winds prevented opening the 6.5 m Magellan/Clay telescope on Las Campanas, Chile, with its own frame-transfer camera, and clouds obscured the 1.9 m telescope at Sutherland, South Africa, which had POETS. With shadow velocity 23.6 km/s, it was a rapid event: maximum occultation <2 minutes.

The observations were supported in part by grants NNX08AO50G to Williams College and NNX10AB27G to MIT from NASA's Planetary Astronomy Division, and NNH08AI17I to USNO for astrometry. Student participation was supported in part by NASA's Massachusetts Space Grant and NSF's REU. Japan's government donated U. Chile's Cerro Calan Goto telescope. PROMPT observations were made possible by the Robert Martin Ayers Science Fund. TRAPPIST is a project driven by the University of Liège, in close collaboration with the Observatory of Geneva, supported by the Belgian Fund for Scientific Research and the Swiss National Science Foundation. Title: TRAPPIST : un télescope liégeois à la découverte des systèmes planétaires Authors: Jehin, E.; Gillon, M.; Chantry, V.; Magain, P. Bibcode: 2010Ciel...72..326J Altcode: No abstract at ADS Title: The Spitzer search for the transits of HARPS low-mass planets. I. No transit for the super-Earth HD 40307b Authors: Gillon, M.; Deming, D.; Demory, B. -O.; Lovis, C.; Seager, S.; Mayor, M.; Pepe, F.; Queloz, D.; Segransan, D.; Udry, S.; Delmelle, S.; Magain, P. Bibcode: 2010A&A...518A..25G Altcode: 2010arXiv1002.4707G We used Spitzer and its IRAC camera to search for the transit of the super-Earth HD 40307b. The hypothesis that the planet transits could not be firmly discarded from our first photometric monitoring of a transit window because of the uncertainty coming from the modeling of the photometric baseline. To obtain a firm result, two more transit windows were observed and a global Bayesian analysis of the three IRAC time series and the HARPS radial velocities was performed. Unfortunately, the hypothesis that the planet transited during the observed phase window is firmly rejected, while the probability that the planet does transit but that the eclipse was missed by our observations is nearly negligible (0.26%).

The photometric time series used in this work are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/518/A25 Title: VizieR Online Data Catalog: Transits of HD40307b by Spitzer (Gillon+, 2010) Authors: Gillon, M.; Deming, D.; Demory, B. -O.; Lovis, C.; Seager, S.; Mayor, M.; Pepe, F.; Queloz, D.; Segransan, D.; Udry, S.; Delmelle, S.; Magain, P. Bibcode: 2010yCat..35180025G Altcode: 2010yCat..35189025G We used Spitzer and its IRAC camera to search for the transit of the super-Earth HD 40307b. The hypothesis that the planet transits could not be firmly discarded from our first photometric monitoring of a transit window because of the uncertainty coming from the modeling of the photometric baseline. To obtain a firm result, two more transit windows were observed and a global Bayesian analysis of the three IRAC time series and the HARPS radial velocities was performed. Unfortunately, the hypothesis that the planet transited during the observed phase window is firmly rejected, while the probability that the planet does transit but that the eclipse was missed by our observations is nearly negligible (0.26%)

(3 data files). Title: Deep near-infrared imaging of the HE0450-2958 system Authors: Letawe, G.; Magain, P. Bibcode: 2010A&A...515A..84L Altcode: 2010arXiv1003.3746L Context. The QSO HE0450-2958 and the companion galaxy with which it is interacting, both ultra luminous in the infrared, have been the subject of much attention in recent years, as the quasar host galaxy remained undetected. This led to various interpretations on QSO and galaxy formation and co-evolution, such as black hole ejection, jet induced star formation, dust obscured galaxy, or normal host below the detection limit.
Aims: We carried out deep observations in the near-IR in order to solve the puzzle concerning the existence of any host.
Methods: The object was observed with the ESO VLT and HAWK-I in the near-IR J-band for 8 h. The images have been processed with the MCS deconvolution method, permitting accurate subtraction of the QSO light from the observations.
Results: The compact emission region situated close to the QSO, called the blob, which previously showed only gas emission lines in the optical spectra, is now detected in our near-IR images. Its high brightness implies that stars likely contribute to the near-IR emission. The blob might thus be interpreted as an off-centre, bright and very compact host galaxy, involved in a violent collision with its companion. Title: Eclipsing binary candidates in Corot-IRa01 field (Carpano+, 2009) Authors: Carpano, S.; Cabrera, J.; Alonso, R.; Barge, P.; Aigrain, S.; Almenara, J. -M.; Borde, P.; Bouchy, F.; Carone, L.; Deeg, H. J.; de La, Reza R.; Deleuil, M.; Dvorak, R.; Erikson, A.; Fressin, F.; Fridlund, M.; Gondoin, P.; Guillot, T.; Hatzes, A.; Jorda, L.; Lammer, H.; Leger, A.; Llebaria, A.; Magain, P.; Moutou, C.; Ofir, A.; Ollivier, M.; Janot-Pacheco, E.; Paetzold, M.; Pont, F.; Queloz, D.; Rauer, H.; Regulo, C.; Renner, S.; Rouan, D.; Samuel, B.; Schneider, J.; Wuchterl, G. Bibcode: 2010yCat..35060491C Altcode: CoRoT observed its first field from early February 2008 until early April, for approximatively 60 days. The run code "IRa01" is explained as following. The "IR" means "initial run" in contrast to the subsequent "long runs" (LR) and "short runs" (SR). The third letter refers to the direction with respect to the Galactic center ("a", as in this case, anticenter or "c" Galactic center). The last two digits are the sequence for this type of observation (01 being the first one).

(1 data file). Title: The Power of Deconvolution for Study of QSO Host Galaxies Authors: Letawe, Géraldine; Letawe, Yannick; Magain, Pierre Bibcode: 2010IAUS..267..117L Altcode: The major challenge in studying QSO host galaxies is to remove the QSO contribution, which often outshines the whole system. Our group has acquired the technical ability to handle such data, for images and slit spectroscopy, as well as integral field spectroscopy. We review here the major techniques developed by our team, and their latest applications. We are open for collaboration with other teams to spread the use of these powerful techniques. Title: Study of a homogeneous QSO sample: relations between the QSO and its host galaxy Authors: Letawe, Y.; Letawe, G.; Magain, P. Bibcode: 2010MNRAS.403.2088L Altcode: 2010arXiv1001.0463L; 2010MNRAS.tmp..217L We analyse a sample of 69 quasi-stellar objects (QSOs) which have been randomly selected in a complete sample of 104 QSOs (R <= 18,0.142 < z < 0.198,δ < 10°). 60 have been observed with the NTT/SUSI2 at La Silla, through two filters in the optical band (WB 655 and V 812), and the remaining nine are taken from archive data bases. The filter V 812 contains the redshifted Hβ and forbidden [OIII] emission lines, while WB 655 covers a spectral region devoid of emission lines, thus measuring the QSO and stellar continua. The contributions of the QSO and the host are separated thanks to the MCS deconvolution algorithm, allowing a morphological classification of the host, and the computation of several parameters such as the host and nucleus absolute V magnitude, distance between the luminosity centre of the host and the QSO and colour of the host and nucleus. We define a new asymmetry coefficient, independent of any galaxy models and well suited for QSO host studies. The main results from this study are (i) 25 per cent of the total number of QSO hosts are spirals, 51 per cent are ellipticals and 60 per cent show signs of interaction, (ii) highly asymmetric systems tend to have a higher gas ionization level and (iii) elliptical hosts contain a substantial amount of ionized gas and some show off-nuclear activity. These results agree with hierarchical models merger driven evolution.

Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile, under programme IDs 77.B-0229 and 78.B-0081.

E-mail: gletawe@ulg.ac.be Title: Transiting exoplanets from the CoRoT space mission. IX. CoRoT-6b: a transiting ``hot Jupiter'' planet in an 8.9d orbit around a low-metallicity star Authors: Fridlund, M.; Hébrard, G.; Alonso, R.; Deleuil, M.; Gandolfi, D.; Gillon, M.; Bruntt, H.; Alapini, A.; Csizmadia, Sz.; Guillot, T.; Lammer, H.; Aigrain, S.; Almenara, J. M.; Auvergne, M.; Baglin, A.; Barge, P.; Bordé, P.; Bouchy, F.; Cabrera, J.; Carone, L.; Carpano, S.; Deeg, H. J.; de La Reza, R.; Dvorak, R.; Erikson, A.; Ferraz-Mello, S.; Guenther, E.; Gondoin, P.; den Hartog, R.; Hatzes, A.; Jorda, L.; Léger, A.; Llebaria, A.; Magain, P.; Mazeh, T.; Moutou, C.; Ollivier, M.; Pätzold, M.; Queloz, D.; Rauer, H.; Rouan, D.; Samuel, B.; Schneider, J.; Shporer, A.; Stecklum, B.; Tingley, B.; Weingrill, J.; Wuchterl, G. Bibcode: 2010A&A...512A..14F Altcode: 2010arXiv1001.1426F The CoRoT satellite exoplanetary team announces its sixth transiting planet in this paper. We describe and discuss the satellite observations as well as the complementary ground-based observations - photometric and spectroscopic - carried out to assess the planetary nature of the object and determine its specific physical parameters. The discovery reported here is a “hot Jupiter” planet in an 8.9d orbit, 18 stellar radii, or 0.08 AU, away from its primary star, which is a solar-type star (F9V) with an estimated age of 3.0 Gyr. The planet mass is close to 3 times that of Jupiter. The star has a metallicity of 0.2 dex lower than the Sun, and a relatively high 7Li abundance. While the light curve indicates a much higher level of activity than, e.g., the Sun, there is no sign of activity spectroscopically in e.g., the [Ca ii] H&K lines.

The CoRoT space mission, launched on December 27, 2006, has been developed and is being operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA, The Research and Scientific Support Department of ESA, Germany and Spain. Title: The thermal emission of the young and massive planet CoRoT-2b at 4.5 and 8 μm Authors: Gillon, M.; Lanotte, A. A.; Barman, T.; Miller, N.; Demory, B. -O.; Deleuil, M.; Montalbán, J.; Bouchy, F.; Collier Cameron, A.; Deeg, H. J.; Fortney, J. J.; Fridlund, M.; Harrington, J.; Magain, P.; Moutou, C.; Queloz, D.; Rauer, H.; Rouan, D.; Schneider, J. Bibcode: 2010A&A...511A...3G Altcode: 2009arXiv0911.5087G We report measurements of the thermal emission of the young and massive planet CoRoT-2b at 4.5 and 8 μm with the Spitzer Infrared Array Camera (IRAC). Our measured occultation depths are 0.510±0.042% at 4.5 and 0.41±0.11% at 8 μm. In addition to the CoRoT optical measurements, these planet/star flux ratios indicate a poor heat distribution on the night side of the planet and agree better with an atmosphere free of temperature inversion layer. Still, such an inversion is not definitely ruled out by the observations and a larger wavelength coverage is required to remove the current ambiguity. Our global analysis of CoRoT, Spitzer, and ground-based data confirms the high mass and large size of the planet with slightly revised values (M_p = 3.47±0.22 MJ, R_p = 1.466±0.044 RJ). We find a small but significant offset in the timing of the occultation when compared to a purely circular orbital solution, leading to e \cosω = -0.00291±0.00063 where e is the orbital eccentricity and ω is the argument of periastron. Constraining the age of the system to at most a few hundred Myr and assuming that the non-zero orbital eccentricity does not come from a third undetected body, we modeled the coupled orbital-tidal evolution of the system with various tidal Q values, core sizes, and initial orbital parameters. For Q_s' = 105-106, our modeling is able to explain the large radius of CoRoT-2b if Q_p'≤ 105.5 through a transient tidal circularization and corresponding planet tidal heating event. Under this model, the planet will reach its Roche limit within 20 Myr at most.

Based on data collected with the VLT/FORS2 instrument at ESO Paranal Observatory, Chile (programs 081.C-0413(B)).

The photometric timeseries used in this work are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/511/A3 Title: Transit timing analysis of CoRoT-1b Authors: Csizmadia, Sz.; Renner, S.; Barge, P.; Agol, E.; Aigrain, S.; Alonso, R.; Almenara, J. -M.; Bonomo, A. S.; Bordé, P.; Bouchy, F.; Cabrera, J.; Deeg, H. J.; de La Reza, R.; Deleuil, M.; Dvorak, R.; Erikson, A.; Guenther, E. W.; Fridlund, M.; Gondoin, P.; Guillot, T.; Hatzes, A.; Jorda, L.; Lammer, H.; Lázaro, C.; Léger, A.; Llebaria, A.; Magain, P.; Moutou, C.; Ollivier, M.; Pätzold, M.; Queloz, D.; Rauer, H.; Rouan, D.; Schneider, J.; Wuchterl, G.; Gandolfi, D. Bibcode: 2010A&A...510A..94C Altcode: 2009arXiv0911.3585C Context. CoRoT, the pioneer space-based transit search, steadily provides thousands of high-precision light curves with continuous time sampling over periods of up to 5 months. The transits of a planet perturbed by an additional object are not strictly periodic. By studying the transit timing variations (TTVs), additional objects can be detected in the system.
Aims: A transit timing analysis of CoRoT-1b is carried out to constrain the existence of additional planets in the system.
Methods: We used data obtained by an improved version of the CoRoT data pipeline (version 2.0). Individual transits were fitted to determine the mid-transit times, and we analyzed the derived O-C diagram. N-body integrations were used to place limits on secondary planets.
Results: No periodic timing variations with a period shorter than the observational window (55 days) are found. The presence of an Earth-mass Trojan is not likely. A planet of mass greater than ~1 Earth mass can be ruled out by the present data if the object is in a 2:1 (exterior) mean motion resonance with CoRoT-1b. Considering initially circular orbits: (i) super-Earths (less than 10 Earth-masses) are excluded for periods less than about 3.5 days; (ii) Saturn-like planets can be ruled out for periods less than about 5 days; (iii) Jupiter-like planets should have a minimum orbital period of about 6.5 days.

Based on observations obtained with CoRoT, a space project operated by the French Space Agency, CNES, with participation of the Science Programs of ESA, ESTEC/RSSD, Austria, Belgium, Brazil, Germany, and Spain. Title: High-dispersion infrared spectroscopic observations of comet 8P/Tuttle with VLT/CRIRES Authors: Kobayashi, H.; Bockelée-Morvan, D.; Kawakita, H.; Dello Russo, N.; Jehin, E.; Manfroid, J.; Smette, A.; Hutsemékers, D.; Stüwe, J.; Weiler, M.; Arpigny, C.; Biver, N.; Cochran, A.; Crovisier, J.; Magain, P.; Sana, H.; Schulz, R.; Vervack, R. J.; Weaver, H.; Zucconi, J. -M. Bibcode: 2010A&A...509A..80K Altcode: We report on the composition of the Halley-family comet (HFC) 8P/Tuttle investigated with high-dispersion near-infrared spectroscopic observations. The observations were carried out at the ESO VLT (Very Large Telescope) with the CRIRES instrument as part of a multi-wavelength observation campaign of 8P/Tuttle performed in late January and early February 2008. Radar observations suggested that 8P/Tuttle is a contact binary, and it was proposed that these components might be heterogeneous in chemistry. We determined mixing ratios of organic volatiles with respect to H2O and found that mixing ratios were consistent with previous near infrared spectroscopic observations obtained in late December 2007 and in late January 2008. It has been suggested that because 8P/Tuttle is a contact binary, it might be chemically heterogeneous. However, we find no evidence for chemical heterogeneity within the nucleus of 8P/Tuttle. We also compared the mixing ratios of organic molecules in 8P/Tuttle with those of both other HFCs and long period comets (LPCs) and found that HCN, C2H2, and C2H6 are depleted whereas CH4 and CH3OH have normal abundances. This may indicate that 8P/Tuttle was formed in a different region of the early solar nebula than other HFCs and LPCs. We estimated the conversion efficiency from C2H2 to C2H6 by hydrogen addition reactions on cold grains by employing the C2H6/(C2H6+C2H2) ratio. The C2H6/(C2H6+C2H2) ratio in 8P/Tuttle is consistent with the ratios found in other HFCs and LPCs within the error bars. We also discuss the source of C2 and CN based on our observations and conclude that the abundances of C2H2 and C2H6 are insufficient to explain the C2 abundances in comet 8P/Tuttle and that the abundance of HCN is insufficient to explain the CN abundances in the comet, so at least one additional parent is needed for each species, as pointed out in previous study.

Based on observations collected at the European Southern Observatory, Paranal, Chile (ESO Prog. 080.C-0615 and 280.C-5053).We regret to note the death of Dr. J. -M. Zucconi in 2009 May. Title: Eclipsing binaries in CoRoT-LRc01 field (Cabrera+, 2009) Authors: Cabrera, J.; Fridlund, M.; Ollivier, M.; Gandolfi, D.; Csizmadia, Sz.; Alonso, R.; Aigrain, S.; Alapini, A.; Almenara, J. -M.; Barge, P.; Bonomo, A. S.; Borde, P.; Bouchy, F.; Bruntt, H.; Carone, L.; Carpano, S.; Deeg, H. J.; de La, Reza R.; Deleuil, M.; Dvorak, R.; Erikson, A.; Gillon, M.; Gondoin, P.; Guenther, E. W.; Guillot, T.; Hartmann, M.; Hatzes, A.; Hebrard, G.; Jorda, L.; Lammer, H.; Leger, A.; Llebaria, A.; Lovis, C.; Magain, P.; Mayor, M.; Mazeh, T.; Moutou, C.; Ofir, A.; Paetzold, M.; Pepe, F.; Pont, F.; Queloz, D.; Rabus, M.; Rauer, H.; Regulo, C.; Renner, S.; Rouan, D.; Samuel, B.; Santerne, A.; Schneider, J.; Shporer, A.; Stecklum, B.; Tingley, B.; Udry, S.; Wuchterl, G. Bibcode: 2010yCat..35060501C Altcode: The 11408 targets observed by CoRoT were selected using the information gathered in the database Exo-Dat (Deleuil et al. 2009AJ....138..649D; Meunier et al. 2007, ASP Conf., 376, 339), built with dedicated ground based photometric observations in the visible and near IR bands from 2MASS catalog.

(3 data files). Title: Study of Quasar Host Galaxies Combining HST/ACS Images and VLT Spectra Authors: Letawe, Yannick; Letawe, Géraldine; Magain, Pierre Bibcode: 2010ASSP...15..197L Altcode: 2010ihea.book..197L We present the results of a study of the host galaxies of a few bright low redshift quasars, based on a combination of high resolution HST/ACS images with deep VLT spectra. Using a version of the MCS deconvolution algorithm specially adapted to HST images, the light from the central point source can be efficiently removed, which allows to study the environment of the quasar down to a few hundreds of parsecs from the center. In a similar way, the spectra can be separated into a quasar contribution and a spatially resolved slit spectrum of the host galaxy. Combining the images and spectra allows to carry out a detailed analysis of the immediate environment of the quasar: excitation and ionization state of the gas, dynamics… Up to now, this method has been applied to six quasars, including the peculiar HE0450-2958 (Magain et al. in Nature 437:381, 2005), for which no host galaxy could be detected. Title: VizieR Online Data Catalog: Light curves of CoRoT-2 in z-band, 4.5um and 8um (Gillon+, 2010) Authors: Gillon, M.; Lanotte, A. A.; Barman, T.; Miller, N.; Demory, B. -O.; Deleuil, M.; Montalban, J.; Bouchy, F.; Collier, Cameron A.; Deeg, H. J.; Fortney, J. J.; Fridlund, M.; Harrington, J.; Magain, P.; Moutou, C.; Queloz, D.; Rauer, H.; Rouan, D.; Schneider, J. Bibcode: 2009yCat..35110003G Altcode: 2009yCat..35119003G Photometric time series obtained for CoRoT-2 with the VLT/FORS2 camera in z band during a transit of the planet CoRoT-2b and with the SST/IRAC camera at 4.5 and 8um during an occultation of the same planet.

(3 data files). Title: Transiting exoplanets from the CoRoT space mission. VII. The ``hot-Jupiter''-type planet CoRoT-5b Authors: Rauer, H.; Queloz, D.; Csizmadia, Sz.; Deleuil, M.; Alonso, R.; Aigrain, S.; Almenara, J. M.; Auvergne, M.; Baglin, A.; Barge, P.; Bordé, P.; Bouchy, F.; Bruntt, H.; Cabrera, J.; Carone, L.; Carpano, S.; de La Reza, R.; Deeg, H. J.; Dvorak, R.; Erikson, A.; Fridlund, M.; Gandolfi, D.; Gillon, M.; Guillot, T.; Guenther, E.; Hatzes, A.; Hébrard, G.; Kabath, P.; Jorda, L.; Lammer, H.; Léger, A.; Llebaria, A.; Magain, P.; Mazeh, T.; Moutou, C.; Ollivier, M.; Pätzold, M.; Pont, F.; Rabus, M.; Renner, S.; Rouan, D.; Shporer, A.; Samuel, B.; Schneider, J.; Triaud, A. H. M. J.; Wuchterl, G. Bibcode: 2009A&A...506..281R Altcode: 2009arXiv0909.3397R Aims: The CoRoT space mission continues to photometrically monitor about 12 000 stars in its field-of-view for a series of target fields to search for transiting extrasolar planets ever since 2007. Deep transit signals can be detected quickly in the “alarm-mode” in parallel to the ongoing target field monitoring. CoRoT's first planets have been detected in this mode.
Methods: The CoRoT raw lightcurves are filtered for orbital residuals, outliers, and low-frequency stellar signals. The phase folded lightcurve is used to fit the transit signal and derive the main planetary parameters. Radial velocity follow-up observations were initiated to secure the detection and to derive the planet mass.
Results: We report the detection of CoRoT-5b, detected during observations of the LRa01 field, the first long-duration field in the galactic anti-center direction. CoRoT-5b is a “hot Jupiter-type” planet with a radius of 1.388+0.046-0.047 R_Jup, a mass of 0.467+0.047-0.024 M_Jup, and therefore, a mean density of 0.217+0.031-0.025 g cm-3. The planet orbits an F9V star of 14.0 mag in 4.0378962 ± 0.0000019 days at an orbital distance of 0.04947+0.00026-0.00029 AU.

Observations made with SOPHIE spectrograph at the Observatoire de Haute Provence (07B.PNP.MOUT), France, and HARPS spectrograph at ESO La Silla Observatory (072.C-0488(E), 082.C-0312(A)), and partly based on observations made at the Anglo-Australian Telescope. The CoRoT space mission, launched on December 27, 2006, was developed and is operated by CNES, with the contribution of Austria, Belgium, Brasil, ESA, Germany, and Spain. Title: VLT transit and occultation photometry for the bloated planet CoRoT-1b Authors: Gillon, M.; Demory, B. -O.; Triaud, A. H. M. J.; Barman, T.; Hebb, L.; Montalbán, J.; Maxted, P. F. L.; Queloz, D.; Deleuil, M.; Magain, P. Bibcode: 2009A&A...506..359G Altcode: 2009arXiv0905.4571G We present VLT eclipse photometry for the giant planet CoRoT-1b. We observed a transit in the R-band filter and an occultation in a narrow filter centered on 2.09 μm. Our analysis of this new photometry and published radial velocities, in combination with stellar-evolutionary modeling, leads to a planetary mass and radius of 1.07+0.13-0.18 M_Jup and 1.45+0.07-0.13 R_Jup, confirming the very low density previously deduced from CoRoT photometry. The large occultation depth that we measure at 2.09 μm (0.278+0.043-0.066%) is consistent with thermal emission and is better reproduced by an atmospheric model with no redistribution of the absorbed stellar flux to the night side of the planet.

Based on data collected with the VLT/FORS2 and VLT/HAWK-I instruments at ESO Paranal Observatory, Chile (programs 080.C-0661(B) and 382.C-0642(A)). The photometric time-series used in this work are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/506/359 Title: Planetary transit candidates in CoRoT-LRc01 field Authors: Cabrera, J.; Fridlund, M.; Ollivier, M.; Gandolfi, D.; Csizmadia, Sz.; Alonso, R.; Aigrain, S.; Alapini, A.; Almenara, J. -M.; Barge, P.; Bonomo, A. S.; Bordé, P.; Bouchy, F.; Bruntt, H.; Carone, L.; Carpano, S.; Deeg, H. J.; de La Reza, R.; Deleuil, M.; Dvorak, R.; Erikson, A.; Gillon, M.; Gondoin, P.; Guenther, E. W.; Guillot, T.; Hartmann, M.; Hatzes, A.; Hebrard, G.; Jorda, L.; Lammer, H.; Léger, A.; Llebaria, A.; Lovis, C.; Magain, P.; Mayor, M.; Mazeh, T.; Moutou, C.; Ofir, A.; Pätzold, M.; Pepe, F.; Pont, F.; Queloz, D.; Rabus, M.; Rauer, H.; Régulo, C.; Renner, S.; Rouan, D.; Samuel, B.; Santerne, A.; Schneider, J.; Shporer, A.; Stecklum, B.; Tingley, B.; Udry, S.; Wuchterl, G. Bibcode: 2009A&A...506..501C Altcode: Aims: We present here the list of planetary transit candidates detected in the first long run observed by CoRoT: LRc01, towards the galactic center in the direction of Aquila, which lasted from May to October 2007.
Methods: we analyzed 3719 (33%) sources in the chromatic bands and 7689 in the monochromatic band. Instrumental noise and the stellar variability were treated with several detrending tools, on which subsequently several transit search algorithms were applied.
Results: Forty two sources were classified as planetary transit candidates and up to now 26 cases have been solved. One planet (CoRoT-2b) and one brown-dwarf (CoRoT-3b) have been the subjects of detailed publications.

The CoRoT space mission, launched on December 27 2006, was developed and is operated by CNES, with contributions from Austria, Belgium, Brazil, ESA, Germany and Spain. The first CoRoT data are available to the community from the CoRoT archive: http://idoc-corot.ias.u-psud.fr. Title: Planetary transit candidates in the CoRoT initial run: resolving their nature Authors: Moutou, C.; Pont, F.; Bouchy, F.; Deleuil, M.; Almenara, J. M.; Alonso, R.; Barbieri, M.; Bruntt, H.; Deeg, H. J.; Fridlund, M.; Gandolfi, D.; Gillon, M.; Guenther, E.; Hatzes, A.; Hébrard, G.; Loeillet, B.; Mayor, M.; Mazeh, T.; Queloz, D.; Rabus, M.; Rouan, D.; Shporer, A.; Udry, S.; Aigrain, S.; Auvergne, M.; Baglin, A.; Barge, P.; Benz, W.; Bordé, P.; Carpano, S.; de La Reza, R.; Dvorak, R.; Erikson, A.; Gondoin, P.; Guillot, T.; Jorda, L.; Kabath, P.; Lammer, H.; Léger, A.; Llebaria, A.; Lovis, C.; Magain, P.; Ollivier, M.; Pätzold, M.; Pepe, F.; Rauer, H.; Schneider, J.; Wuchterl, G. Bibcode: 2009A&A...506..321M Altcode: With the release of CoRoT lightcurves of the Initial Run IRa01, 50 transiting planetary candidates have been published in a companion paper. About twenty of them were identified as binary stars from the CoRoT lightcurve itself. Complementary observations were conducted for 29 candidates, including ground-based photometry and radial-velocity measurements. Two giant planets were identified and fully characterized. Nineteen binaries are recognized, from which 10 are background eclipsing binaries in the CoRoT mask or triple systems, diluted by the main CoRoT target. Eight cases remain of unclear origin, one of them still being a planetary candidate. Comparison with simulations shows that the actual threshold of confirmed planet detection in this field does not yet fulfill the expectations, and a number of reasons are invoked, like the ranking process based on lightcurve analyses, and the strategy and limits of follow-up observations for targets fainter than magnitude 15.

Based on data obtained at Observatoire de Haute Provence with SOPHIE and with HARPS on the ESO 3.6 m telescope at La Silla Observatory. The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil , ESA (RSSD and Science Programme), Germany and Spain.

Tables 2 to 13, 15 to 17 and Figs. 4 to 7 are only available in electronic form at http://www.aanda.org Title: Planetary transit candidates in Corot-IRa01 field Authors: Carpano, S.; Cabrera, J.; Alonso, R.; Barge, P.; Aigrain, S.; Almenara, J. -M.; Bordé, P.; Bouchy, F.; Carone, L.; Deeg, H. J.; de La Reza, R.; Deleuil, M.; Dvorak, R.; Erikson, A.; Fressin, F.; Fridlund, M.; Gondoin, P.; Guillot, T.; Hatzes, A.; Jorda, L.; Lammer, H.; Léger, A.; Llebaria, A.; Magain, P.; Moutou, C.; Ofir, A.; Ollivier, M.; Janot-Pacheco, E.; Pätzold, M.; Pont, F.; Queloz, D.; Rauer, H.; Régulo, C.; Renner, S.; Rouan, D.; Samuel, B.; Schneider, J.; Wuchterl, G. Bibcode: 2009A&A...506..491C Altcode: 2009arXiv0907.5150C Context: CoRoT is a pioneering space mission devoted to the analysis of stellar variability and the photometric detection of extrasolar planets.
Aims: We present the list of planetary transit candidates detected in the first field observed by CoRoT, IRa01, the initial run toward the Galactic anticenter, which lasted for 60 days.
Methods: We analysed 3898 sources in the coloured bands and 5974 in the monochromatic band. Instrumental noise and stellar variability were taken into account using detrending tools before applying various transit search algorithms.
Results: Fifty sources were classified as planetary transit candidates and the most reliable 40 detections were declared targets for follow-up ground-based observations. Two of these targets have so far been confirmed as planets, CoRoT-1b and CoRoT-4b, for which a complete characterization and specific studies were performed.

The CoRoT space mission, launched on December 27th 2006,

has been developed and is operated by CNES, with contributions from Austria, Belgium, Brazil, ESA,

Germany, and Spain. Four

French laboratories associated with the CNRS (LESIA, LAM, IAS ,OMP) collaborate with CNES on the satellite development.

First CoRoT data are available to the public from the CoRoT archive: http://idoc-corot.ias.u-psud.fr. Title: Removing systematics from the CoRoT light curves. I. Magnitude-dependent zero point Authors: Mazeh, T.; Guterman, P.; Aigrain, S.; Zucker, S.; Grinberg, N.; Alapini, A.; Alonso, R.; Auvergne, M.; Barbieri, M.; Barge, P.; Bordé, P.; Bouchy, F.; Deeg, H.; de La Reza, R.; Deleuil, M.; Dvorak, R.; Erikson, A.; Fridlund, M.; Gondoin, P.; Jorda, L.; Lammer, H.; Léger, A.; Llebaria, A.; Magain, P.; Moutou, C.; Ollivier, M.; Pätzold, M.; Pont, F.; Queloz, D.; Rauer, H.; Rouan, D.; Sabo, R.; Schneider, J.; Wuchterl, G. Bibcode: 2009A&A...506..431M Altcode: 2009arXiv0907.2237M This paper presents an analysis that searched for systematic effects within the CoRoT exoplanet field light curves. The analysis identified a systematic effect that modified the zero point of most CoRoT exposures as a function of stellar magnitude. We could find this effect only after preparing a set of learning light curves that were relatively free of stellar and instrumental noise. Correcting for this effect, rejecting outliers that appear in almost every exposure, and applying SysRem, reduced the stellar RMS by about 20%, without attenuating transit signals.

The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA, Germany, and Spain. CoRoT data become publicly available one year after release to the Co-Is of the mission from the CoRoT archive: http://idoc-corot.ias.u-psud.fr/. Title: Rate and nature of false positives in the CoRoT exoplanet search Authors: Almenara, J. M.; Deeg, H. J.; Aigrain, S.; Alonso, R.; Auvergne, M.; Baglin, A.; Barbieri, M.; Barge, P.; Bordé, P.; Bouchy, F.; Bruntt, H.; Cabrera, J.; Carone, L.; Carpano, S.; Catala, C.; Csizmadia, Sz.; de La Reza, R.; Deleuil, M.; Dvorak, R.; Erikson, A.; Fridlund, M.; Gandolfi, D.; Gillon, M.; Gondoin, P.; Guenther, E.; Guillot, T.; Hatzes, A.; Hébrard, G.; Jorda, L.; Lammer, H.; Léger, A.; Llebaria, A.; Loeillet, B.; Magain, P.; Mayor, M.; Mazeh, T.; Moutou, C.; Ollivier, M.; Pätzold, M.; Pont, F.; Queloz, D.; Rauer, H.; Régulo, C.; Renner, S.; Rouan, D.; Samuel, B.; Schneider, J.; Shporer, A.; Wuchterl, G.; Zucker, S. Bibcode: 2009A&A...506..337A Altcode: 2009arXiv0908.1172A Context: The CoRoT satellite searches for planets by applying the transit method, monitoring up to 12 000 stars in the galactic plane for 150 days in each observing run. This search is contaminated by a large fraction of false positives, caused by different eclipsing binary configurations that might be confused with a transiting planet.
Aims: We evaluate the rates and nature of false positives in the CoRoT exoplanets search and compare our results with semiempirical predictions.
Methods: We consider the detected binary and planet candidates in the first three extended CoRoT runs, and classify the results of the follow-up observations completed to verify their planetary nature. We group the follow-up results into undiluted binaries, diluted binaries, and planets and compare their abundances with predictions from the literature.
Results: 83% of the initial detections are classified as false positives using only the CoRoT light-curves, the remaining 17% require follow-up observations. Finally, 12% of the candidates in the follow-up program are planets. The shape of the overall distribution of the false positive rate follows previous predictions, except for candidates with transit depths below about 0.4%. For candidates with transit depths in the range from 0.1-0.4%, CoRoT detections are nearly complete, and this difference from predictions is probably real and dominated by a lower than expected abundance of diluted eclipsing binaries.

The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil , ESA (RSSD and Science Programme), Germany and Spain. Title: Noise properties of the CoRoT data. A planet-finding perspective Authors: Aigrain, S.; Pont, F.; Fressin, F.; Alapini, A.; Alonso, R.; Auvergne, M.; Barbieri, M.; Barge, P.; Bordé, P.; Bouchy, F.; Deeg, H.; de La Reza, R.; Deleuil, M.; Dvorak, R.; Erikson, A.; Fridlund, M.; Gondoin, P.; Guterman, P.; Jorda, L.; Lammer, H.; Léger, A.; Llebaria, A.; Magain, P.; Mazeh, T.; Moutou, C.; Ollivier, M.; Pätzold, M.; Queloz, D.; Rauer, H.; Rouan, D.; Schneider, J.; Wuchter, G.; Zucker, S. Bibcode: 2009A&A...506..425A Altcode: 2009arXiv0903.1829A In this short paper, we study the photometric precision of stellar light curves obtained by the CoRoT satellite in its planet-finding channel, with a particular emphasis on the time scales characteristic of planetary transits. Together with other articles in the same issue of this journal, it forms an attempt to provide the building blocks for a statistical interpretation of the CoRoT planet and eclipsing binary catch to date. After pre-processing the light curves so as to minimise long-term variations and outliers, we measure the scatter of the light curves in the first three CoRoT runs lasting more than 1 month, using an iterative non-linear filter to isolate signal on the time scales of interest. The behaviour of the noise on 2 h time scales is described well by a power-law with index 0.25 in R-magnitude, ranging from 0.1 mmag at R=11.5 to 1 mmag at R=16, which is close to the pre-launch specification, though still a factor 2-3 above the photon noise due to residual jitter noise and hot pixel events. There is evidence of slight degradation in the performance over time. We find clear evidence of enhanced variability on hour time scales (at the level of 0.5 mmag) in stars identified as likely giants from their R magnitude and B-V colour, which represent approximately 60 and 20% of the observed population in the directions of Aquila and Monoceros, respectively. On the other hand, median correlated noise levels over 2 h for dwarf stars are extremely low, reaching 0.05 mmag at the bright end.

The CoRoT space mission, launched on December 27, 2006, has been developed and is operated by the CNES, with the contribution of Austria, Belgium, Brazil, ESA, Germany, and Spain. CoRoT data become publicly available one year after release to the Co-Is of the mission from the CoRoT archive: http://idoc-corot.ias.u-psud.fr/. Title: The secondary eclipse of CoRoT-1b Authors: Alonso, R.; Alapini, A.; Aigrain, S.; Auvergne, M.; Baglin, A.; Barbieri, M.; Barge, P.; Bonomo, A. S.; Bordé, P.; Bouchy, F.; Chaintreuil, S.; de La Reza, R.; Deeg, H. J.; Deleuil, M.; Dvorak, R.; Erikson, A.; Fridlund, M.; de Oliveira Fialho, F.; Gondoin, P.; Guillot, T.; Hatzes, A.; Jorda, L.; Lammer, H.; Léger, A.; Llebaria, A.; Magain, P.; Mazeh, T.; Moutou, C.; Ollivier, M.; Pätzold, M.; Pont, F.; Queloz, D.; Rauer, H.; Rouan, D.; Schneider, J.; Wuchterl, G. Bibcode: 2009A&A...506..353A Altcode: 2009arXiv0907.1653A The transiting planet CoRoT-1b is thought to belong to the pM-class of planets, in which the thermal emission dominates in the optical wavelengths. We present a detection of its secondary eclipse in the CoRoT white channel data, whose response function goes from ~400 to ~1000 nm. We used two different filtering approaches, and several methods to evaluate the significance of a detection of the secondary eclipse. We detect a secondary eclipse centered within 20 min at the expected times for a circular orbit, with a depth of 0.016 ± 0.006%. The center of the eclipse is translated in a 1-σ upper limit to the planet's eccentricity of e cosω< 0.014. Under the assumption of a zero Bond Albedo and blackbody emission from the planet, it corresponds to a T_CoRoT = 2330+120-140 K. We provide the equilibrium temperatures of the planet as a function of the amount of reflected light. If the planet is in thermal equilibrium with the incident flux from the star, our results imply an inefficient transport mechanism of the flux from the day to the night sides.

Based on observations obtained with CoRoT, a space project operated by the French Space Agency, CNES, with participation of the Science Programme of ESA, ESTEC/RSSD, Austria, Belgium, Brazil, Germany and Spain. Title: VizieR Online Data Catalog: CoRoT-7 radial velocities (Queloz+, 2009) Authors: Queloz, D.; Bouchy, F.; Moutou, C.; Hatzes, A.; Hebrard, G.; Alonso, R.; Auvergne, M.; Baglin, A.; Barbieri, M.; Barge, P.; Benz, W.; Borde, P.; Deeg, H. J.; Deleuil, M.; Dvorak, R.; Erikson, A.; Ferraz Mello, S.; Fridlund, M.; Gandolfi, D.; Gillon, M.; Guenther, E.; Guillot, T.; Jorda, L.; Hartmann, M.; Lammer, H.; Leger, A.; Llebaria, A.; Lovis, C.; Magain, P.; Mayor, M.; Mazeh, T.; Ollivier, M.; Patzold, M.; Pepe, F.; Rauer, H.; Rouan, D.; Schneider, J.; Segransan, D.; Udry, S.; Wuchterl, G. Bibcode: 2009yCat..35060303Q Altcode: First, a simple pre-whitening procedure was employed to find and subsequently remove periodic signals from the complex frequency structure of the radial velocity data. The dominant frequency in the power spectrum was found at 23 days, which corresponds to the rotation period of CoRoT-7. The 0.8535 day period of CoRoT-7b planetary candidate was detected with an amplitude of 3.3m/s.

(1 data file). Title: The CoRoT-7 planetary system: two orbiting super-Earths Authors: Queloz, D.; Bouchy, F.; Moutou, C.; Hatzes, A.; Hébrard, G.; Alonso, R.; Auvergne, M.; Baglin, A.; Barbieri, M.; Barge, P.; Benz, W.; Bordé, P.; Deeg, H. J.; Deleuil, M.; Dvorak, R.; Erikson, A.; Ferraz Mello, S.; Fridlund, M.; Gandolfi, D.; Gillon, M.; Guenther, E.; Guillot, T.; Jorda, L.; Hartmann, M.; Lammer, H.; Léger, A.; Llebaria, A.; Lovis, C.; Magain, P.; Mayor, M.; Mazeh, T.; Ollivier, M.; Pätzold, M.; Pepe, F.; Rauer, H.; Rouan, D.; Schneider, J.; Segransan, D.; Udry, S.; Wuchterl, G. Bibcode: 2009A&A...506..303Q Altcode: We report on an intensive observational campaign carried out with HARPS at the 3.6 m telescope at La Silla on the star CoRoT-7. Additional simultaneous photometric measurements carried out with the Euler Swiss telescope have demonstrated that the observed radial velocity variations are dominated by rotational modulation from cool spots on the stellar surface. Several approaches were used to extract the radial velocity signal of the planet(s) from the stellar activity signal. First, a simple pre-whitening procedure was employed to find and subsequently remove periodic signals from the complex frequency structure of the radial velocity data. The dominant frequency in the power spectrum was found at 23 days, which corresponds to the rotation period of CoRoT-7. The 0.8535 day period of CoRoT-7b planetary candidate was detected with an amplitude of 3.3 m s-1. Most other frequencies, some with amplitudes larger than the CoRoT-7b signal, are most likely associated with activity. A second approach used harmonic decomposition of the rotational period and up to the first three harmonics to filter out the activity signal from radial velocity variations caused by orbiting planets. After correcting the radial velocity data for activity, two periodic signals are detected: the CoRoT-7b transit period and a second one with a period of 3.69 days and an amplitude of 4 m s-1. This second signal was also found in the pre-whitening analysis. We attribute the second signal to a second, more remote planet CoRoT-7c . The orbital solution of both planets is compatible with circular orbits. The mass of CoRoT-7b is 4.8±0.8 (M⊕) and that of CoRoT-7c is 8.4± 0.9 (M⊕), assuming both planets are on coplanar orbits. We also investigated the false positive scenario of a blend by a faint stellar binary, and this may be rejected by the stability of the bisector on a nightly scale. According to their masses both planets belong to the super-Earth planet category. The average density of CoRoT-7b is ρ=5.6± 1.3 g cm-3, similar to the Earth. The CoRoT-7 planetary system provides us with the first insight into the physical nature of short period super-Earth planets recently detected by radial velocity surveys. These planets may be denser than Neptune and therefore likely made of rocks like the Earth, or a mix of water ice and rocks.

Based on observations made with HARPS spectrograph on the 3.6-m ESO telescope and the EULER Swiss telescope at La Silla Observatory, Chile. The HARPS results presented in this paper (Appendix A) are available in electronic form at http://www.aanda.org and at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/506/303 Title: A Multi-Wavelength Simultaneous Study of the Composition of the Halley Family Comet 8P/Tuttle Authors: Jehin, E.; Bockelée-Morvan, D.; Dello Russo, N.; Manfroid, J.; Hutsemékers, D.; Kawakita, H.; Kobayashi, H.; Schulz, R.; Smette, A.; Stüwe, J.; Weiler, M.; Arpigny, C.; Biver, N.; Cochran, A.; Crovisier, J.; Magain, P.; Rauer, H.; Sana, H.; Vervack, R. J.; Weaver, H.; Zucconi, J. -M. Bibcode: 2009EM&P..105..343J Altcode: 2009EM&P..tmp...38J We report on simultaneous optical and infrared observations of the Halley Family comet 8P/Tuttle performed with the ESO Very Large Telescope. Such multi-wavelength and coordinated observations are a good example of what can be done to support space missions. From high resolution optical spectroscopy of the CN (0,0) 388 nm and NH2 (0,9,0) 610 nm bands using UVES at UT2 we determined 12C/13C = 90 ± 10 and 14N/15N = 150 ± 20 in CN and we derived a nuclear spin temperature of NH3 of 29 ± 1 K. These values are similar to those found in Oort-Cloud and Jupiter Family comets. From low resolution long slit spectroscopy with FORS1 at UT2 we determined the CN, C3 and C2 production rates and the parent and daughter scale lengths up to 5.2 105 km tailward. From high resolution IR spectroscopy with CRIRES at UT1 we measured simultaneously the production rates and mixing ratios of H2O, HCN, C2H2, CH4, C2H6, and CH3OH. Title: Near-infrared observations of the HE0450-2958 system: discovery of a second active galactic nucleus? Authors: Letawe, G.; Magain, P.; Chantry, V.; Letawe, Y. Bibcode: 2009MNRAS.396...78L Altcode: 2009arXiv0903.1718L The quasi-stellar object (QSO) HE0450-2958 was brought to the front scene by the non-detection of its host galaxy and strong upper limits on the latter's luminosity. The QSO is also a powerful infrared emitter, in gravitational interaction with a strongly distorted ultraluminous infrared companion galaxy. We investigate the properties of the companion galaxy, through new near- and mid-infrared observations of the system obtained with Near Infrared Camera and Multi-Object Spectrometer (NICMOS) onboard Hubble Space Telescope, Infrared Spectrometer and Array Camera (ISAAC) and Very Large Telescope Imager and Spectrometer in the Infrared (VISIR) on the European Southern Observatory Very Large Telescope. The companion galaxy is found to harbour a point source revealed only in the infrared, in what appears as a hole or dark patch in the optical images. Various hypotheses on the nature of this point source are analysed and it is found that the only plausible one is that it is a strongly reddened active galactic nucleus hidden behind a thick dust cloud. The hypothesis that the QSO supermassive black hole might have been ejected from the companion galaxy in the course of a galactic collision involving three-body black holes interaction is also reviewed, on the basis of this new insight on a definitely complex system.

Based on observations made with the ESO Very Large Telescope at ESO Paranal Observatory, Chile, under program IDs 076.B-0693(C), 276.B-5011 and NASA/ESA HST program 10797 during cycle 15.

E-mail: gletawe@ulg.ac.be Title: VizieR Online Data Catalog: FORS2 and HAWKI photometry of CoRoT-1 (Gillon+, 2009) Authors: Gillon, M.; Demory, B. -O.; Triaud, A. H. M. J.; Barman, T.; Hebb, L.; Montalban, J.; Maxted, P. F. L.; Queloz, D.; Deleuil, M.; Magain, P. Bibcode: 2009yCat..35060359G Altcode: We present VLT eclipse photometry for the giant planet CoRoT-1b. We observed a transit in the R-band filter and an occultation in a narrow filter centered on 2.09{mu}m. Our analysis of this new photometry and published radial velocities, in combination with stellar-evolutionary modeling, leads to a planetary mass and radius of 1.07+0.13-0.18M{Jup} and 1.45+0.07-0.13R_{Jup}, confirming the very low density previously deduced from CoRoT photometry. The large occultation depth that we measure at 2.09{mu}m (0.2780.043-0.066% ) is consistent with thermal emission and is better reproduced by an atmospheric model with no redistribution of the absorbed stellar flux to the night side of the planet.

(2 data files). Title: Transiting exoplanets from the CoRoT space mission. IV. CoRoT-Exo-4b: a transiting planet in a 9.2 day synchronous orbit Authors: Aigrain, S.; Collier Cameron, A.; Ollivier, M.; Pont, F.; Jorda, L.; Almenara, J. M.; Alonso, R.; Barge, P.; Bordé, P.; Bouchy, F.; Deeg, H.; de La Reza, R.; Deleuil, M.; Dvorak, R.; Erikson, A.; Fridlund, M.; Gondoin, P.; Gillon, M.; Guillot, T.; Hatzes, A.; Lammer, H.; Lanza, A. F.; Léger, A.; Llebaria, A.; Magain, P.; Mazeh, T.; Moutou, C.; Paetzold, M.; Pinte, C.; Queloz, D.; Rauer, H.; Rouan, D.; Schneider, J.; Wuchter, G.; Zucker, S. Bibcode: 2008A&A...488L..43A Altcode: 2008arXiv0807.3767A CoRoT, the first space-based transit search, provides ultra-high-precision light curves with continuous time-sampling over periods of up to 5 months. This allows the detection of transiting planets with relatively long periods, and the simultaneous study of the host star's photometric variability. In this Letter, we report the discovery of the transiting giant planet CoRoT-Exo-4b and use the CoRoT light curve to perform a detailed analysis of the transit and determine the stellar rotation period. The CoRoT light curve was pre-processed to remove outliers and correct for orbital residuals and artefacts due to hot pixels on the detector. After removing stellar variability about each transit, the transit light curve was analysed to determine the transit parameters. A discrete autocorrelation function method was used to derive the rotation period of the star from the out-of-transit light curve. We determine the periods of the planetary orbit and star's rotation of 9.20205 ± 0.00037 and 8.87 ± 1.12 days respectively, which is consistent with this being a synchronised system. We also derive the inclination, i = 90.00_-0.085+0.000 in degrees, the ratio of the orbital distance to the stellar radius, a/Rs = 17.36-0.25+0.05, and the planet-to-star radius ratio R_p/R_s=0.1047-0.0022+0.0041. We discuss briefly the coincidence between the orbital period of the planet and the stellar rotation period and its possible implications for the system's migration and star-planet interaction history.

The CoRoT space mission, launched on

December 27th 2006, has been developed and is operated by

CNES, with the contribution of Austria, Belgium, Brazil, ESA,

Germany, and Spain. The first CoRoT data will be available to the

public in February 2009 from the CoRoT archive: http://idoc-corot.ias.u-psud.fr/

Figures 1, 4 and 5 are only available in electronic form at http://www.aanda.org Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses. VII. Time delays and the Hubble constant from WFI J2033-4723 Authors: Vuissoz, C.; Courbin, F.; Sluse, D.; Meylan, G.; Chantry, V.; Eulaers, E.; Morgan, C.; Eyler, M. E.; Kochanek, C. S.; Coles, J.; Saha, P.; Magain, P.; Falco, E. E. Bibcode: 2008A&A...488..481V Altcode: 2008arXiv0803.4015V Gravitationally lensed quasars can be used to map the mass distribution in lensing galaxies and to estimate the Hubble constant H0 by measuring the time delays between the quasar images. Here we report the measurement of two independent time delays in the quadruply imaged quasar WFI J2033-4723 (z = 1.66). Our data consist of R-band images obtained with the Swiss 1.2 m EULER telescope located at La Silla and with the 1.3 m SMARTS telescope located at Cerro Tololo. The light curves have 218 independent epochs spanning 3 full years of monitoring between March 2004 and May 2007, with a mean temporal sampling of one observation every 4th day. We measure the time delays using three different techniques, and we obtain Δ tB-A = 35.5 ± 1.4 days (3.8%) and Δ tB-C = 62.6+ 4.1- 2.3~days ~ (+ 6.5%- 3.7%), where A is a composite of the close, merging image pair. After correcting for the time delays, we find R-band flux ratios of FA/FB = 2.88 ± 0.04, FA/FC = 3.38 ± 0.06, and FA1/FA2 = 1.37 ± 0.05 with no evidence for microlensing variability over a time scale of three years. However, these flux ratios do not agree with those measured in the quasar emission lines, suggesting that longer term microlensing is present. Our estimate of H0 agrees with the concordance value: non-parametric modeling of the lensing galaxy predicts H0 = 67+13-10 km s-1 Mpc-1, while the Single Isothermal Sphere model yields H0 = 63+7-3 km s-1 Mpc-1 (68% confidence level). More complex lens models using a composite de Vaucouleurs plus NFW galaxy mass profile show twisting of the mass isocontours in the lensing galaxy, as do the non-parametric models. As all models also require a significant external shear, this suggests that the lens is a member of the group of galaxies seen in field of view of WFI J2033-4723.

Based on observations obtained with the 1.2 m EULER Swiss Telescope, the 1.3 m Small and Moderate Aperture Research Telescope System (SMARTS) which is operated by the SMARTS Consortium, and the NASA/ESA Hubble Space Telescope as part of program HST-GO-9744 of the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. Table 4 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/488/481 Title: Transiting exoplanets from the CoRoT space mission. V. CoRoT-Exo-4b: stellar and planetary parameters Authors: Moutou, C.; Bruntt, H.; Guillot, T.; Shporer, A.; Guenther, E.; Aigrain, S.; Almenara, J. M.; Alonso, R.; Auvergne, M.; Baglin, A.; Barbieri, M.; Barge, P.; Benz, W.; Bordé, P.; Bouchy, F.; Deeg, H. J.; de La Reza, R.; Deleuil, M.; Dvorak, R.; Erikson, A.; Fridlund, M.; Gillon, M.; Gondoin, P.; Hatzes, A.; Hébrard, G.; Jorda, L.; Kabath, P.; Lammer, H.; Léger, A.; Llebaria, A.; Loeillet, B.; Magain, P.; Mayor, M.; Mazeh, T.; Ollivier, M.; Pätzold, M.; Pepe, F.; Pont, F.; Queloz, D.; Rabus, M.; Rauer, H.; Rouan, D.; Schneider, J.; Udry, S.; Wuchterl, G. Bibcode: 2008A&A...488L..47M Altcode: 2008arXiv0807.3739M Aims: The CoRoT satellite has announced its fourth transiting planet (Aigrain et al. 2008, A&A, 488, L43) with space photometry. We describe and analyse complementary observations of this system performed to establish the planetary nature of the transiting body and to estimate the fundamental parameters of the planet and its parent star.
Methods: We have analysed high precision radial-velocity data, ground-based photometry, and high signal-to-noise ratio spectroscopy.
Results: The parent star CoRoT-Exo-4 (2MASS 06484671-0040219) is a late F-type star of mass of 1.16 M⊙ and radius of 1.17 R⊙. The planet has a circular orbit with a period of 9.20205 d. The planet radius is 1.19 R_Jup and the mass is 0.72 M_Jup. It is a gas-giant planet with a “normal” internal structure of mainly H and He. CoRoT-Exo-4b has the second longest period of the known transiting planets. It is an important discovery since it occupies an empty area in the mass-period diagram of transiting exoplanets.

Based on observations obtained with CoRoT, a space project operated by the French Space Agency, CNES, with participation of the Science Programme of ESA, ESTEC/RSSD, Austria, Belgium, Brazil, Germany and Spain; and on observations made with the SOPHIE spectrograph at Observatoire de Haute Provence, France (PNP.07B.MOUT), and the HARPS spectrograph at ESO La Silla Observatory (079.C-0127/F).

Table 2 and Fig. 5 are only available in electronic form at http://www.aanda.org Title: High-dispersion Spectroscopic Observations Of 8P/Tuttle With VLT/CRIRES Authors: Kobayashi, Hitomi; Bockelee-Morvan, D.; Dello Russo, N.; Kawakita, H.; Verback, R. J.; Weaver, H.; Jehin, E.; Manfroid, J.; Smette, A.; Cochran, A.; Hutsemekers, D.; Schulz, R.; Stuwe, J.; Weiler, M.; Zucconi, J.; Arpigny, C.; Biver, N.; Crovisier, J.; Magain, P.; Rauer, H.; Sana, H. Bibcode: 2008DPS....40.0504K Altcode: 2008BAAS...40..394K We present near-infrared observations of organic molecules in comet 8P/Tuttle.

Comet 8P/Tuttle is a Halley-type comet and its last perihelion was in early January 2008. Our observations were carried out on January 28 and February 4 using CRIRES (CRyogenic high-resolution InfraRed Echelle Spectrograph) at the Very Large Telescope (VLT). We used a 0.2" slit which provided a spectral resolving power of 80,000. We detected H2O, OH, HCN, C2H2 on Jan 28, and H2O, OH, CH4, C2H6, and CH3OH on Feb 4.

We find that 8P/Tuttle is depleted in HCN, C2H2 and C2H6 relative to H2O compared with most other Oort cloud comets studied to date. Perhaps these depletions suggest that 8P/Tuttle formed in a different region from most Oort cloud comets, but it is also possible that the depletions are caused by repeated passages through the inner solar system. Title: VizieR Online Data Catalog: Time delays and H0 from WFI J2033-4723 (Vuissoz+, 2008) Authors: Vuissoz, C.; Courbin, F.; Sluse, D.; Meylan, G.; Chantry, V.; Eulaers, E.; Morgan, C.; Eyler, M. E.; Kochanek, C. S.; Coles, J.; Saha, P.; Magain, P.; Falco, E. E. Bibcode: 2008yCat..34880481V Altcode: Photometry of WFI J2033-4723, as in Fig. 3 of the paper. The first column gives the Julian date and corresponds to HJD days. The second column is the seeing, in arcsec. Column 3-8 display the photometric measurements of the quasar components A, B and C respectively, with the corresponding error bars. The last column finally provides the name of the telescope used for each measurement.

(1 data file). Title: Understanding the Relations between QSOs and Their Host Galaxies from Combined HST Imaging and VLT Spectroscopy Authors: Letawe, Y.; Magain, P.; Letawe, G.; Courbin, F.; Hutsemékers, D. Bibcode: 2008ApJ...679..967L Altcode: 2008arXiv0802.1386L The host galaxies of six nearby QSOs are studied on the basis of high-resolution HST optical images and spatially resolved VLT slit spectra. The gas ionization and velocity are mapped as a function of the distance to the central QSO. In the majority of the cases, the QSO significantly contributes to the gas ionization in its whole host galaxy, and sometimes even outside. Reflection or scattering of the QSO Hα line from remote regions of the galaxy is detected in several instances. The line shifts show that, in all cases, the matter responsible for the light reflection moves away from the QSO, likely accelerated by its radiation pressure. The two faintest QSOs reside in spirals, with some signs of a past gravitational perturbation. One of the intermediate-luminosity QSOs resides in a massive elliptical containing gas ionized (and probably pushed away) by the QSO radiation. The other medium-power object is found in a spiral galaxy displaying complex velocity structure, with the central QSO moving with respect to the bulge, probably as a result of a galactic collision. The two most powerful objects are involved in violent gravitational interactions, and one of them has no detected host. These results suggest that (1) large-scale phenomena, such as galactic collisions, are closely related to the triggering and the feeding of the QSO and (2) once ignited, the QSO has significant influence on its large-scale neighborhood (often the whole host and sometimes further away).

Based on observations made with the Nasa/ESA Hubble Space Telescope (Cycle 13 proposal 10238), and with ANTU/UT1 at ESO-Paranal observatory in Chile [programs 65.P-0361(A) and 66.B-0139(A)]. Title: Transiting exoplanets from the CoRoT space mission. II. CoRoT-Exo-2b: a transiting planet around an active G star Authors: Alonso, R.; Auvergne, M.; Baglin, A.; Ollivier, M.; Moutou, C.; Rouan, D.; Deeg, H. J.; Aigrain, S.; Almenara, J. M.; Barbieri, M.; Barge, P.; Benz, W.; Bordé, P.; Bouchy, F.; de La Reza, R.; Deleuil, M.; Dvorak, R.; Erikson, A.; Fridlund, M.; Gillon, M.; Gondoin, P.; Guillot, T.; Hatzes, A.; Hébrard, G.; Kabath, P.; Jorda, L.; Lammer, H.; Léger, A.; Llebaria, A.; Loeillet, B.; Magain, P.; Mayor, M.; Mazeh, T.; Pätzold, M.; Pepe, F.; Pont, F.; Queloz, D.; Rauer, H.; Shporer, A.; Schneider, J.; Stecklum, B.; Udry, S.; Wuchterl, G. Bibcode: 2008A&A...482L..21A Altcode: 2008arXiv0803.3207A Context: The CoRoT mission, a pioneer in exoplanet searches from space, has completed its first 150 days of continuous observations of ~12 000 stars in the galactic plane. An analysis of the raw data identifies the most promising candidates and triggers the ground-based follow-up.
Aims: We report on the discovery of the transiting planet CoRoT-Exo-2b, with a period of 1.743 days, and characterize its main parameters.
Methods: We filter the CoRoT raw light curve of cosmic impacts, orbital residuals, and low frequency signals from the star. The folded light curve of 78 transits is fitted to a model to obtain the main parameters. Radial velocity data obtained with the SOPHIE, CORALIE and HARPS spectrographs are combined to characterize the system. The 2.5 min binned phase-folded light curve is affected by the effect of sucessive occultations of stellar active regions by the planet, and the dispersion in the out of transit part reaches a level of 1.09×10-4 in flux units.
Results: We derive a radius for the planet of 1.465 ± 0.029 R_Jup and a mass of 3.31 ± 0.16 M_Jup, corresponding to a density of 1.31 ± 0.04 g/cm^3. The large radius of CoRoT-Exo-2b cannot be explained by current models of evolution of irradiated planets.

Based on observations obtained with CoRoT, a space project operated by the French Space Agency, CNES, with participation of the Science Programme of ESA, ESTEC/RSSD, Austria, Belgium, Brazil, Germany and Spain; and on observations made with SOPHIE spectrograph at Observatoire de Haute Provence, France (PNP.07 A.MOUT), CORALIE, and HARPS spectrograph at ESO La Silla Observatroy (079.C-0127/F)).

Table 2 is only available in electronic form at http://www.aanda.org Title: Transiting exoplanets from the CoRoT space mission. I. CoRoT-Exo-1b: a low-density short-period planet around a G0V star Authors: Barge, P.; Baglin, A.; Auvergne, M.; Rauer, H.; Léger, A.; Schneider, J.; Pont, F.; Aigrain, S.; Almenara, J. -M.; Alonso, R.; Barbieri, M.; Bordé, P.; Bouchy, F.; Deeg, H. J.; La Reza, De; Deleuil, M.; Dvorak, R.; Erikson, A.; Fridlund, M.; Gillon, M.; Gondoin, P.; Guillot, T.; Hatzes, A.; Hebrard, G.; Jorda, L.; Kabath, P.; Lammer, H.; Llebaria, A.; Loeillet, B.; Magain, P.; Mazeh, T.; Moutou, C.; Ollivier, M.; Pätzold, M.; Queloz, D.; Rouan, D.; Shporer, A.; Wuchterl, G. Bibcode: 2008A&A...482L..17B Altcode: 2008arXiv0803.3202B Context: The pioneer space mission for photometric planet searches, CoRoT, steadily monitors about 12 000 stars in each of its fields of view. Transit candidates can be detected early in the processing of the data and before the end of a run of observation.
Aims: We report the detection of the first planet discovered by CoRoT and characterizing it with the help of follow-up observations.
Methods: Raw data were filtered from outliers and residuals at the orbital period of the satellite. The orbital parameters and the radius of the planet were estimated by best fitting the phase folded light curve with 34 successive transits. Doppler measurements with the SOPHIE spectrograph permitted us to secure the detection against binaries and to estimate the mass of the planet.
Results: The accuracy of the data is very high with a dispersion in the 2.17 min binned phase-folded light curve that does not exceed ~3.×10-4 in flux unit. The planet orbits a mildly metal-poor G0V star of magnitude V=13.6 in 1.5 days. The estimated mass and radius of the star are 0.95±0.15 M⊙ and 1.11±0.05 R⊙. We find the planet has a radius of 1.49±0.08 R_Jup, a mass of 1.03±0.12 M_Jup, and a particularly low mean density of 0.38±0.05 g cm-3.

The CoRoT space mission, launched on Dec. 27th, 2006, was developed and is operated by the CNES, with participation of the Science Program of ESA, ESTEC/RSSD, Austria, Belgium, Brazil, Germany and Spain. Based in part on observations with the SOPHIE spectrograph at Obs. de Haute Provence, France. Table [see full text] is only available in electronic form at http://www.aanda.org Individual photometric measurements are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/482/L17 Title: Transiting exoplanets from the CoRoT space mission. III. The spectroscopic transit of CoRoT-Exo-2b with SOPHIE and HARPS Authors: Bouchy, F.; Queloz, D.; Deleuil, M.; Loeillet, B.; Hatzes, A. P.; Aigrain, S.; Alonso, R.; Auvergne, M.; Baglin, A.; Barge, P.; Benz, W.; Bordé, P.; Deeg, H. J.; de La Reza, R.; Dvorak, R.; Erikson, A.; Fridlund, M.; Gondoin, P.; Guillot, T.; Hébrard, G.; Jorda, L.; Lammer, H.; Léger, A.; Llebaria, A.; Magain, P.; Mayor, M.; Moutou, C.; Ollivier, M.; Pätzold, M.; Pepe, F.; Pont, F.; Rauer, H.; Rouan, D.; Schneider, J.; Triaud, A. H. M. J.; Udry, S.; Wuchterl, G. Bibcode: 2008A&A...482L..25B Altcode: 2008arXiv0803.3209B We report on the spectroscopic transit of the massive hot-Jupiter CoRoT-Exo-2b observed with the high-precision spectrographs SOPHIE and HARPS. By modeling the radial velocity anomaly occurring during the transit due to the Rossiter-McLaughlin (RM) effect, we determine the sky-projected angle between the stellar spin and the planetary orbital axis to be close to zero λ = 7.2 ± 4.5 deg, and we secure the planetary nature of CoRoT-Exo-2b. We discuss the influence of the stellar activity on the RM modeling. Spectral analysis of the parent star from HARPS spectra are presented.

Observations made with SOPHIE spectrograph at Observatoire de Haute Provence, France (PNP.07A.MOUT) and HARPS spectrograph at ESO La Silla Observatory (079.C-0127(F)). The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brasil, ESA, Germany, and Spain. Title: Quasar Host Orientation and Polarization: Insights into the Type 1/Type 2 Dichotomy Authors: Borguet, B.; Hutsemékers, D.; Letawe, G.; Letawe, Y.; Magain, P. Bibcode: 2008RMxAC..32..167B Altcode: 2007arXiv0710.4072B We investigate correlations between the optical linear polarization position angle and the orientation of the host galaxy/extended emission of Type 1 and Type 2 Radio-Loud (RL) and Radio-Quiet (RQ) quasars. We have used high resolution Hubble Space Telescope (HST) data and deconvolution process to obtain a good determination of the host galaxy orientation. With these new measurements and a compilation of data from the literature, we find a significant correlation between the polarization position angle and the position angle of the major axis of the host galaxy/extended emission. The correlation appears different for Type 1 and Type 2 objects and depends on the redshift of the source. Interpretations in the framework of the unification model are discussed. Title: VizieR Online Data Catalog: CoRoT space mission. I. (Barge+, 2008) Authors: Barge, P.; Baglin, A.; Auvergne, M.; Rauer, H.; Leger, A.; Schneider, J.; Pont, F.; Aigrain, S.; Almenara, J. -M.; Alonso, R.; Barbieri, M.; Borde, P.; Bouchy, F.; Deeg, H. J.; de La, R. Reza; Deleuil, M.; Dvorak, R.; Erikson, A.; Fridlund, M.; Gillon, M.; Gondoin, P.; Guillot, T.; Hatzes, A.; Hebrard, G.; Jorda, L.; Kabath, P.; Lammer, H.; Llebaria, A.; Loeillet, B.; Magain, P.; Mazeh, T.; Moutou, C.; Ollivier, M.; Patzold, M.; Queloz, D.; Rouan, D.; Shporer, A. Bibcode: 2008yCat..34829017B Altcode: Raw data were filtered from outliers and residuals at the orbital period of the satellite. The orbital parameters and the radius of the planet were estimated by best fitting the phase folded light curve with 34 successive transits. Doppler measurements with the SOPHIE spectrograph permitted us to secure the detection against binaries and to estimate the mass of the planet.

The individual photometric measurements will be available after the proprietary period of the CoRoT project. See http://smsc.cnes.fr/COROT for more information Title: Slit and integral-field optical spectroscopy of the enigmatic quasar HE 0450-2958 Authors: Letawe, G.; Magain, P.; Courbin, F. Bibcode: 2008A&A...480...69L Altcode: 2007arXiv0709.3743L Context: Interest in the quasar HE 0450-2958 arose following the publication of the non-detection of its expected massive host, leading to various interpretations.
Aims: This article investigates the gaseous and stellar contents of the system through additional VLT/FORS slit spectra and integral field spectroscopy from VLT/VIMOS.
Methods: We apply our MCS deconvolution algorithm on slit spectra for the separation of the QSO and diffuse components, and develop a new method to remove the point sources in Integral Field Spectra, allowing extraction of velocity maps, narrow-line images, spatially resolved spectra or ionization diagrams of the surroundings of HE 0450-2958.
Results: The whole system is embedded in gas, mostly ionized by the QSO radiation field and shocks associated with radio jets. The observed gas and star dynamics are unrelated, revealing a strongly perturbed system. Despite longer spectroscopic observations, the host galaxy remains undetected.

Based on observations made with VLT/UT1 (program 76.B-0693(B)), and with the VLT/UT3 (program 72.B-0268(B)) at ESO-Paranal observatory in Chile, in addition with NASA/ESA Hubble Space Telescope observations from Cycle 13, proposal #10238. Title: Evidence of a type 1/type 2 dichotomy in the correlation between quasar optical polarization and host-galaxy/extended emission position angles Authors: Borguet, B.; Hutsemékers, D.; Letawe, G.; Letawe, Y.; Magain, P. Bibcode: 2008A&A...478..321B Altcode: 2007arXiv0710.4048B Aims:For Seyfert galaxies, the AGN unification model provides a simple and well-established explanation of the type 1/type 2 dichotomy through orientation-based effects. The generalization of this unification model to the higher luminosity AGNs that quasars are remains a key question. The recent detection of type 2 radio-quiet quasars seems to support such an extension. We propose a further test of this scenario.
Methods: On the basis of a compilation of quasar host-galaxy position angles consisting of previously published data and of new measurements performed using HST Archive images, we investigate the possible existence of a correlation between the linear polarization position angle and the host-galaxy/extended emission position angle of quasars.
Results: We find that the orientation of the rest-frame UV/blue extended emission is correlated to the direction of the quasar polarization. For type 1 quasars, the polarization is aligned with the extended UV/blue emission, while these two quantities are perpendicular in type 2 objects. This result is independent of the quasar radio loudness. We interpret this (anti-)alignment effect in terms of scattering in a two-component polar+equatorial model that applies to both type 1 and type 2 objects. Moreover, the orientation of the polarization -and then of the UV/blue scattered light- does not appear correlated to the major axis of the stellar component of the host-galaxy measured from near-IR images. Title: Study of the QSO HE0354-5500 with combined HST imaging and VLT spectroscopy . An example of a deconvolution-based method for probing the QSOs host galaxies characteristics Authors: Letawe, Y.; Magain, P.; Letawe, G.; Courbin, F.; Hutsemékers, D. Bibcode: 2008MmSAI..79.1251L Altcode: The host galaxy of the QSO HE0354-5500 (M_B=-24.7, z=0.2674) is studied on the basis of high resolution HST optical images and spatially resolved VLT slit spectra. The morphology and dynamics of the host are described. The gas ionization and velocity are mapped as a function of the distance to the central QSO. Reflection or scattering of the QSO Halpha line from remote regions of the galaxy is detected. The line shifts show that the matter responsible for the light reflection moves away from the QSO, likely accelerated by its radiation pressure. Moreover, different resolved emission regions are found in the central kpc, both in the images and the spectra. Title: A Multi-Wavelength Simultaneous Study of the Composition of the Halley-Family Comet 8P/Tuttle at the VLT Authors: Bockelée-Morvan, D.; Dello Russo, N.; Jehin, E.; Manfroid, J.; Smette, A.; Cochran, A.; Hutsemékers, D.; Kawakita, H.; Kobayashi, H.; Schulz, R.; Weiler, M.; Zucconi, J. M.; Arpigny, C.; Biver, N.; Crovisier, J.; Magain, P.; Rauer, H.; Sana, H.; Vervack, R. J.; Weaver, H. Bibcode: 2008LPICo1405.8190B Altcode: No abstract at ADS Title: VizieR Online Data Catalog: QSO Type1/Type2 dichotomy (Borguet+, 2008) Authors: Borguet, B.; Hutsemekers, D.; Letawe, G.; Letawe, Y.; Magain, P. Bibcode: 2007yCat..34780321B Altcode: This table contains the measurements/compilation of host galaxy/ extended emission position angle in the visible and near-IR domain, polarimetric data, and radio axis orientation for the 135 quasars of our sample. The angles are given in degrees east of north. The table gives the spectral and the radio-loud/radio-quiet classification of each object according to the references.

(2 data files). Title: Deconvolution of HST images of the Cloverleaf gravitational lens. Detection of the lensing galaxy and a partial Einstein ring Authors: Chantry, V.; Magain, P. Bibcode: 2007A&A...470..467C Altcode: 2006astro.ph.12094C Archival HST/NICMOS-2 images of the Cloverleaf gravitational lens (H1413+117), a quadruply-imaged quasar, were analysed with a new method derived from the MCS deconvolution algorithm (Magain et al. 1998). This method is based on an iterative process which simultaneously allows us to determine the Point Spread Function (PSF) and to perform a deconvolution of images containing several point sources plus extended structures. As such, it is well-adapted to the processing of gravitational lens images, especially in the case of multiply-imaged quasars. Two sets of data were analysed: the first one, which was obtained through the F160W filter in 1997, basically corresponds to a continuum image, while the second one, obtained through the narrower F180M filter in 2003, is centered around the forbidden [Oiii] emission lines at the source redshift, thus probing the narrow-line region of the quasar. The deconvolution gives astrometric and photometric measurements in both filters and reveals the primary lensing galaxy as well as a partial Einstein ring. The high accuracy of the results is particularly important in order to model the lensing system and to reconstruct the source undergoing the strong lensing. The reliability of the method is checked on a synthetic image similar to H1413+117.

Based on observations made with the NASA/ESA HST Hubble Space Telescope, obtained from the data archive at the Space Science Institute. STScI is operated by AURA, the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS-5-26555. Title: DECPHOT: An Optimal Deconvolution-based Photometric Reduction Method Authors: Gillon, M.; Magain, P.; Chantry, V.; Letawe, G.; Sohy, S.; Courbin, F.; Pont, F.; Moutou, C. Bibcode: 2007ASPC..366..113G Altcode: 2007astro.ph..1607G A high accuracy photometric reduction method is needed to take full advantage of the potential of the transit method for the detection and characterization of exoplanets, especially in deep crowded fields. In this context, we present DECPHOT, a new deconvolution-based photometry algorithm able to deal with a very high level of crowding and large variations of seeing. It also increases the resolution of astronomical images, an important advantage for the discrimination of false positives in transit photometry. Title: On the Influence of Blends on the Potential of Ground-based Transit Surveys Authors: Gillon, M.; Magain, P. Bibcode: 2007ASPC..366..283G Altcode: 2007astro.ph..1609G Transit surveys have to observe many stars all at once in order to compensate for the rarity of the searched events. Such surveys, especially the ones observing a deep field of view and/or broadening their stellar images, have to deal with a relatively high level of crowding. This crowding could lead to a reduction of the number of detectable transits, and the estimation of the potential of such surveys without taking into account the influence of blends could give overoptimistic results. We have developed a code which allows to estimate the extent by which such a survey is affected by the crowding of the field of view. Our results show that the influence of blends is important only for severe levels of crowding and is in general much less crucial than the influence of red noise. Title: On-axis spectroscopy of the host galaxies of 20 optically luminous quasars at z ~ 0.3 Authors: Letawe, G.; Magain, P.; Courbin, F.; Jablonka, P.; Jahnke, K.; Meylan, G.; Wisotzki, L. Bibcode: 2007MNRAS.378...83L Altcode: 2007MNRAS.tmp..450L; 2006astro.ph..5288L We present the analysis of a sample of 20 bright low-redshift quasars (MB < -23 and z < 0.35) observed spectroscopically with the Very Large Telescope (VLT). The Focal Reducer/low dispersion Spectrograph (FORS1) spectra, obtained in Multi-Object Spectroscopy (MOS) mode, allow to observe simultaneously the quasars and several reference stars used to spatially deconvolve the data. Applying the Magain, Courbin & Sohy (MCS) deconvolution method, we are able to separate the individual spectra of the quasar and of the underlying host galaxy. Contrary to some previous claims, we find that luminous quasars are not exclusively hosted by massive ellipticals. Most quasar host galaxies harbour large amounts of gas, irrespective of their morphological type. Moreover, the stellar content of half of the hosts is a young Sc-like population, associated with a rather low-metallicity interstellar medium. A significant fraction of the galaxies contain gas ionized at large distances by the quasar radiation. This large distance ionization is always associated with signs of gravitational interactions (as detected from images or disturbed rotation curves). The spectra of the quasars themselves provide evidence that gravitational interactions bring dust and gas in the immediate surrounding of the super massive black hole, allowing to feed it. The quasar activity might thus be triggered (1) in young gas-rich spiral galaxies by local events and (2) in more evolved galaxies by gravitational interactions or collisions. The latter mechanism gives rises to the most powerful quasars. Finally, we derive mass models for the isolated spiral host galaxies and we show that the most reliable estimators of the systemic redshift in the quasar spectrum are the tips of the Hα and Hβ lines.

Based on observations made with the European Southern Observatory (ESO) Very Large Telescope Unit 1 (ANTU/UT1) at ESO Paranal Observatory, Chile, under program IDs 65.P-0361 and 66.B-0139.

E-mail: gletawe@ulg.ac.be Title: The transiting planet OGLE-TR-132b revisited with new spectroscopy and deconvolution photometry, Authors: Gillon, M.; Pont, F.; Moutou, C.; Santos, N. C.; Bouchy, F.; Hartman, J. D.; Mayor, M.; Melo, C.; Queloz, D.; Udry, S.; Magain, P. Bibcode: 2007A&A...466..743G Altcode: 2007astro.ph..2192G OGLE-TR-132b transits a very metal-rich F dwarf about 2000 pc from the Sun, in the Galactic disc towards Carina. It orbits very close to its host star (a = 0.03 AU) and has an equilibrium temperature of nearly 2000 K. Using rapid-cadence transit photometry from the FORS2 camera on the VLT and SUSI2 on the NTT, and high-resolution spectroscopy with UVES on the VLT, we refine the shape of the transit light curve and the parameters of the system. In particular, we improve the planetary radius estimate, R = 1.18 ± 0.07 RJ and provide very precise ephemeris, T_tr = 2 453 142.59123 ± 0.0003 BJD and P = 1.689868 ± 0.000003 days. The obtained planetary mass is 1.14 ± 0.12 M_J. Our results give a slightly smaller and lighter star, and bigger planet, than previous values. As the VLT/FORS2 light curve obtained in this analysis with the deconvolution photometry algorithm DECPHOT shows a transit depth in disagreement with the one obtained by a previous study using the same data, we analyze them with two other reduction methods (aperture and image subtraction). The light curves obtained with the three methods are in good agreement, though deconvolution-based photometry is significantly more precise. It appears from these results that the smaller transit depth obtained in the previous study was due to a normalisation problem inherent to the reduction procedure used.

Based on data collected with the FORS2 imager at the VLT-UT4 telescope (Paranal Observatory, ESO, Chile) in the programme 273.C-5017A, with the SUSI2 imager at the NTT telescope (La Silla Observatory, ESO, Chile) in the programme 075.C-0462A, and with the UVES spectrograph at the VLT-UT2 telescope (Paranal Observatory, ESO, Chile) in the programme 076.C-0131. The reduced photometric data used in this work are available only in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/466/743 Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses. V. The time delay in SDSS J1650+4251 Authors: Vuissoz, C.; Courbin, F.; Sluse, D.; Meylan, G.; Ibrahimov, M.; Asfandiyarov, I.; Stoops, E.; Eigenbrod, A.; Le Guillou, L.; van Winckel, H.; Magain, P. Bibcode: 2007A&A...464..845V Altcode: 2006astro.ph..6317V Aims:Our aim is to measure the time delay between the two gravitationally lensed images of the z_qso = 1.547 quasar SDSS J1650+4251, in order to estimate the Hubble constant H_0.
Methods: Our measurement is based on R-band light curves with 57 epochs obtained at Maidanak Observatory, in Uzbekistan, from May 2004 to September 2005. The photometry is performed using simultaneous deconvolution of the data, which provides the individual light curves of the otherwise blended quasar images. The time delay is determined from the light curves using two very different numerical techniques, i.e., polynomial fitting and direct cross-correlation. The time delay is converted into H0 following analytical modeling of the potential well.
Results: Our best estimate of the time delay is Δ t = 49.5 ± 1.9 days, i.e., we reach a 3.8% accuracy. The R-band flux ratio between the quasar images, corrected for the time delay and for slow microlensing, is F_A/FB = 6.2 ± 5%.
Conclusions: .The accuracy reached on the time delay allows us to discriminate well between families of lens models. As for most other multiply imaged quasars, only models of the lensing galaxy that have a de Vaucouleurs mass profile plus external shear give a Hubble constant compatible with the current most popular value (H0 = 72 ± 8 km s-1 Mpc-1). A more realistic singular isothermal sphere model plus external shear gives H0 = 51.7+4.0-3.0 km s-1 Mpc-1.

Table [see full text] is only available in electronic form at http://www.aanda.org Title: VizieR Online Data Catalog: Transiting planet OGLE-TR-132b (Gillon+, 2007) Authors: Gillon, M.; Pont, F.; Moutou, C.; Santos, C. N.; Bouchy, F.; Hartman, D. J.; Mayor, M.; Melo, C.; Queloz, D.; Udry, S.; Magain, P. Bibcode: 2007yCat..34660743G Altcode: We present high-precision photometric coverage of two transits of the planet OGLE-TR-132b. These data have been obtained with the FORS2 camera on the VLT and the SUSI2 on the NTT. Both transits have been observed in the R filter. The deconvolution-based method DECPHOT (Gillon et al., 2006A&A...459..249G, Magain et al., 2007A&A...461..373M, Gillon et al., 2007, in prep.) was used to reduce the data.

(2 data files). Title: A deconvolution-based algorithm for crowded field photometry with unknown point spread function Authors: Magain, P.; Courbin, F.; Gillon, M.; Sohy, S.; Letawe, G.; Chantry, V.; Letawe, Y. Bibcode: 2007A&A...461..373M Altcode: 2006astro.ph..9600M A new method is presented for determining the point

spread function (PSF) of images that lack bright and isolated

stars. It is based on the same principles as the MCS image

deconvolution algorithm. It uses the

information contained in all stellar images to achieve

the double task of reconstructing the PSFs for single or multiple

exposures of the same field and to extract the photometry of

all point sources in the field of view. The use of the full

information available allows us to construct an accurate PSF. The

possibility to simultaneously consider several exposures makes it

well suited to the measurement of the

light curves of blended point sources from data that would be

very difficult or even impossible to analyse with traditional PSF

fitting techniques.

The potential of the method for the

analysis of ground-based and space-based data is tested on

artificial images and illustrated by several examples, including

HST/NICMOS images of a lensed quasar and VLT/ISAAC images of

a faint blended Mira star in the halo of the giant elliptical

galaxy NGC 5128 (Cen A). Title: High accuracy transit photometry of the planet OGLE-TR-113b with a new deconvolution-based method Authors: Gillon, M.; Pont, F.; Moutou, C.; Bouchy, F.; Courbin, F.; Sohy, S.; Magain, P. Bibcode: 2006A&A...459..249G Altcode: 2006astro.ph..6395G A high accuracy photometry algorithm is needed to take full advantage of the potential of the transit method for the characterization of exoplanets, especially in deep crowded fields. It has to reduce to the lowest possible level the negative influence of systematic effects on the photometric accuracy. It should also be able to cope with a high level of crowding and with large-scale variations of the spatial resolution from one image to another. A recent deconvolution-based photometry algorithm fulfills all these requirements, and it also increases the resolution of astronomical images, which is an important advantage for the detection of blends and the discrimination of false positives in transit photometry. We made some changes to this algorithm

to optimize it for transit photometry and used it to reduce NTT/SUSI2 observations of two transits of OGLE-TR-113b. This reduction has led to two very high precision transit light curves with a low level of systematic residuals, used together with former photometric and spectroscopic measurements to derive new stellar and planetary parameters in excellent agreement with previous ones, but significantly more precise. Title: VLT on-axis spectroscopy of quasar host galaxies Authors: Letawe, G.; Magain, P.; Courbin, F.; Jablonka, P.; Meylan, G.; Jahnke, K.; Wisotzki, L. Bibcode: 2006NewAR..50..779L Altcode: We present the full analysis of our sample of 20 bright low redshift quasars (MB < -23 and z < 0.35), observed spectroscopically with the VLT FORS1, with objectives of characterizing the hosts and trying to understand how quasars are fueled or triggered. Applying the MCS deconvolution method, we are able to separate the galactic light from the quasar light, enabling i.e. global analysis of the gaseous and stellar content and gaseous dynamics. We find that 45% of the sample show signs of interaction, while half of the quasars are hosted in spiral galaxies, even when brighter than MV = -23.5. We also find many galaxies containing gas ionized by the quasar radiation far from the nucleus, all of these showing interaction or merger signs. We find spectroscopic evidences that such interactions bring gas in the broad and narrow line regions and power the nucleus. Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses. II. SDSS J0924+0219: the redshift of the lensing galaxy, the quasar spectral variability and the Einstein rings Authors: Eigenbrod, A.; Courbin, F.; Dye, S.; Meylan, G.; Sluse, D.; Vuissoz, C.; Magain, P. Bibcode: 2006A&A...451..747E Altcode: 2005astro.ph.10641E Aims.To provide the observational constraints required to use the gravitationally lensed quasar SDSS J0924+0219 for the determination of H0 from the time delay method. We measure here the redshift of the lensing galaxy, we show the spectral variability of the source, and we resolve the lensed host galaxy of the source.
Methods.We present our VLT/FORS1 deep spectroscopic observations of the lensed quasar SDSS J0924+0219, as well as archival HST/NICMOS and ACS images of the same object. The two-epoch spectra, obtained in the Multi Object Spectroscopy (MOS) mode, allow for very accurate flux calibration and spatial deconvolution. This strategy provides spectra for the lensing galaxy and for the quasar images A and B, free of any mutual light contamination. We deconvolve the HST images as well, which reveal a double Einstein ring. The mass distributions in the lens, reconstructed in several ways, are compared.
Results.We determine the redshift of the lensing galaxy in SDSS J0924+0219: z_lens = 0.394±0.001. Only slight spectral variability is seen in the continuum of quasar images A and B, while the C III] , Mg II and Fe II emission lines display obvious changes. The flux ratio between the quasar images A and B is the same in the emission lines and in the continuum. One of the Einstein rings found using deconvolution corresponds to the lensed quasar host galaxy at z=1.524 and a second bluer one, is the image either of a star-forming region in the host galaxy, or of another unrelated lower redshift object. A broad range of lens models give a satisfactory fit to the data. However, they predict very different time delays, making SDSS J0924+0219 an object of particular interest for photometric monitoring. In addition, the lens models reconstructed using exclusively the constraints from the Einstein rings, or using exclusively the astrometry of the quasar images, are not compatible. This suggests that multipole-like structures play an important role in SDSS J0924+0219.
Title: The Host Galaxies of the Brightest Quasars: Gas-Rich Galaxies, Mergers, and Young Stars Authors: Courbin, Frédéric; Letawe, Géraldine; Meylan, Georges; Magain, Pierre; Jablonka, Pascale; Jahnke, Knud; Wisotzki, Lutz; Letawe, Yannick; North, Pierre Bibcode: 2006Msngr.124...32C Altcode: Because they are faint and hidden in the glare of a much brighter unresolved source, quasar host galaxies still challenge the most powerful telescopes, instrumentation and processing techniques. Determining their basic morphological parameters and their integrated colours is feasible, but difficult, from imaging alone. However, detailed information on their stellar and gas contents and on their dynamics is achievable with deep spectroscopy. Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses. III. Redshift of the lensing galaxy in eight gravitationally lensed quasars Authors: Eigenbrod, A.; Courbin, F.; Meylan, G.; Vuissoz, C.; Magain, P. Bibcode: 2006A&A...451..759E Altcode: 2005astro.ph.11026E Aims.We measure the redshift of the lensing galaxy in eight gravitationally lensed quasars in view of determining the Hubble parameter H0 from the time delay method.
Methods.Deep VLT/FORS1 spectra of lensed quasars are spatially deconvolved in order to separate the spectrum of the lensing galaxies from the glare of the much brighter quasar images. A new observing strategy is devised. It involves observations in Multi-Object-Spectroscopy (MOS) which allows the simultaneous observation of the target and of several PSF and flux calibration stars. The advantage of this method over traditional long-slit observations is a much more reliable extraction and flux calibration of the spectra.
Results.For the first time we measure the redshift of the lensing galaxy in three multiply-imaged quasars: SDSS J1138+0314 (z_lens = 0.445), SDSS J1226-0006 (z_lens = 0.517), SDSS J1335+0118 (z_lens = 0.440), and we give a tentative estimate of the redshift of the lensing galaxy in Q 1355-2257 (z_lens = 0.701). We confirm four previously measured redshifts: HE 0047-1756 (z_lens = 0.407), HE 0230-2130 (z_lens = 0.523), HE 0435-1223 (z_lens = 0.454) and WFI J2033-4723 (z_lens = 0.661). In addition, we determine the redshift of the second lensing galaxy in HE 0230-2130 (z_lens = 0.526). The spectra of all lens galaxies are typical for early-type galaxies, except for the second lensing galaxy in HE 0230-2130 which displays prominent [OII] emission.
Title: High precision determination of the atmospheric parameters and abundances of the COROT main targets Authors: Gillon, M.; Magain, P. Bibcode: 2006A&A...448..341G Altcode: 2005astro.ph.11099G Context: .One of the main goals of the COROT mission is to get precise photometric observations of selected bright stars in order to allow the modelling of their interior through asteroseismology. However, in order to interpret the asteroseismological data, the effective temperature, surface gravity, and chemical composition of the stars must be known with sufficient accuracy.Aims.To carry out this task, we have developed a spectroscopic method called APASS (Atmospheric Parameters and Abundances from Synthetic Spectra) which allows precise analysis of stars with a moderate to high rotational velocity, which is the case for most primary COROT targets.Methods.Our method is based on synthetic spectra in which individual lines are replaced by analysis units (isolated lines or line blends, depending on the crowding of the spectral region and on the rotational broadening). It works differentially with respect to the Sun and allows the atmospheric parameters and chemical abundances to be determined by considering analysis units with different sensitivities to these various parameters.Results.Using high signal-to-noise spectra and the APASS method, we determined the atmospheric parameters and chemical abundances of 13 primary COROT targets. Our results agree well with those obtained by Bruntt using his software VWA and with those obtained with the software TEMPLOGG. However, in both cases, our error bars are significantly smaller than those of other methods. Our effective temperatures are also in excellent agreement with those obtained with the IR photometry method. For five stars with relatively low rotational velocity, we also performed an analysis with a classical equivalent-width method to test agreement with APASS results. We show that equivalent-width measurements by Gaussian or Voigt profile-fitting are sensitive to the rotational broadening, leading to systematic errors whenever the projected rotation velocity is non-negligible. The APASS method appears superior in all cases and should thus be preferred. Title: On the potential of extrasolar planet transit surveys Authors: Gillon, M.; Courbin, F.; Magain, P.; Borguet, B. Bibcode: 2005A&A...442..731G Altcode: 2005astro.ph..8109G We analyse the respective benefits and drawbacks of ground-based and space-based transit surveys for extrasolar planets. Based on simple but realistic assumptions about the fraction of lower main sequence stars harboring telluric and giant planets within the outer limit of the habitable zone, we predict the harvests of fictitious surveys with three existing wide field optical and near-IR cameras: the CFHT-Megacam, SUBARU-Suprime and VISTA-IR. An additional promising instrument is considered, VISTA-Vis, currently under development. The results are compared with the harvests predicted under exactly the same assumptions, for the space missions COROT and KEPLER. We show that ground-based wide field surveys may discover more giant planets than space missions. However, space surveys seem to constitute the best strategy to search for telluric planets. In this respect, the KEPLER mission appears 50 times more efficient than any of the ground-based surveys considered here. KEPLER might even discover telluric planets in the habitable zone of their host star. Title: Photometric monitoring of the doubly imaged quasar UM 673: possible evidence for chromatic microlensing Authors: Nakos, Th.; Courbin, F.; Poels, J.; Libbrecht, C.; Magain, P.; Surdej, J.; Manfroid, J.; Burud, I.; Hjorth, J.; Germany, L.; Lidman, C.; Meylan, G.; Pompei, E.; Pritchard, J.; Saviane, I. Bibcode: 2005A&A...441..443N Altcode: 2005astro.ph..7164N We present the results of two-band CCD photometric monitoring of the gravitationally lensed quasar Q 0142-100 (UM 673). The data, obtained at ESO-La Silla with the 1.54 m Danish telescope in the Gunn i-band (October 1998-September 1999) and in the Johnson V-band (October 1998 to December 2001), were analyzed using three different photometric methods. The light-curves obtained with all methods show variations, with a peak-to-peak amplitude of 0.14 mag in V. Although it was not possible to measure the time delay between the two lensed QSO images, the brighter component displays possible evidence for microlensing: it becomes bluer as it gets brighter, as expected under the assumption of differential magnification of a quasar accretion disk. Title: Chemical abundances in 43 metal-poor stars Authors: Jonsell, K.; Edvardsson, B.; Gustafsson, B.; Magain, P.; Nissen, P. E.; Asplund, M. Bibcode: 2005A&A...440..321J Altcode: 2005astro.ph..5118J We have derived abundances of O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe, Ni, and Ba for 43 metal-poor field stars in the solar neighbourhood, most of them subgiants or turn-off-point stars with iron abundances [Fe/H] ranging from -0.4 to -3.0. About half of this sample has not been spectroscopically analysed in detail before. Effective temperatures were estimated from uvby photometry, and surface gravities primarily from Hipparcos parallaxes. The analysis is differential relative to the Sun, and was carried out with plane-parallel MARCS models. Various sources of error are discussed and found to contribute a total error of about 0.1-0.2 dex for most elements, while relative abundances, such as [Ca/Fe], are most probably more accurate. For the oxygen abundances, determined in an NLTE analysis of the 7774 Å triplet lines, the errors may be somewhat larger. We made a detailed comparison with similar studies and traced the reasons for the, in most cases, relatively small differences. Among the results we find that [O/Fe] possibly increases beyond [Fe/H] = -1.0, though considerably less so than in results obtained by others from abundances based on OH lines. We did not trace any tendency toward strong overionization of iron, and find the excesses, relative to Fe and the Sun, of the α elements Mg, Si, and Ca to be smaller than those of O. We discuss some indications that also the abundances of different α elements relative to Fe vary and the possibility that some of the scatter around the trends in abundances relative to iron may be real. This may support the idea that the formation of Halo stars occurred in smaller systems with different star formation rates. We verify the finding by Gratton et al. (2003b, A&A, 406, 131) that stars that do not participate in the rotation of the galactic disk show a lower mean and larger spread in [ α/Fe] than stars participating in the general rotation. The latter stars also seem to show some correlation between [ α/Fe] and rotation speed. We trace some stars with peculiar abundances, among these two Ba stars, HD 17072 and HD 196944, the second already known to be rich in s elements. Finally we advocate that a spectroscopic study of a larger sample of halo stars with well-defined selection criteria is very important, in order to add to the very considerable efforts that various groups have already made. Title: Discovery of a bright quasar without a massive host galaxy Authors: Magain, Pierre; Letawe, Géraldine; Courbin, Frédéric; Jablonka, Pascale; Jahnke, Knud; Meylan, Georges; Wisotzki, Lutz Bibcode: 2005Natur.437..381M Altcode: 2005astro.ph..9433M A quasar is thought to be powered by the infall of matter onto a supermassive black hole at the centre of a massive galaxy. Because the optical luminosity of quasars exceeds that of their host galaxy, disentangling the two components can be difficult. This led in the 1990s to the controversial claim of the discovery of `naked' quasars. Since then, the connection between quasars and galaxies has been well established. Here we report the discovery of a quasar lying at the edge of a gas cloud, whose size is comparable to that of a small galaxy, but whose spectrum shows no evidence for stars. The gas in the cloud is excited by the quasar itself. If a host galaxy is present, it is at least six times fainter than would normally be expected for such a bright quasar. The quasar is interacting dynamically with a neighbouring galaxy, whose gas might be feeding the black hole. Title: Time Delay in Gravitational Lenses: an Alternative Route to the Hubble Constant Authors: Magain, P. Bibcode: 2005ASPC..335..207M Altcode: The gravitational lens phenomenon is briefly introduced. When several images of the same variable quasar are observed, a determination of the time delay, i.e. the difference in light travel time between these different images can lead to a determination of distances between the source, the lens and the observer and, thus, of the Hubble constant. These determinations are compared to the more classical ones based on standard candles (Cepheids and Type Ia Supernovae). Title: COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses Authors: Courbin, F.; Eigenbrod, A.; Vuissoz, C.; Meylan, G.; Magain, P. Bibcode: 2005IAUS..225..297C Altcode: We describe a new project aiming at measuring time delays for most known lensed quasars, from optical light curves obtained with five (almost) dedicated 1-2 m telescopes in the Northern and Southern hemispheres. The goal is to evaluate the Hubble constant H0 with a precision below 2%. We present here numerical simulations in order to define the optimal temporal sampling in our observations as a function of typical quasar variations, object visibility, and for a given accuracy on the individual photometric points. It is also emphasized that the ongoing effort to obtain deep imaging using both space and ground based facilities must be continued, as illustrated by the comparison of HST and VLT near-IR images of the `cloverleaf': H 1413+117. Title: VizieR Online Data Catalog: Chemical abundances in 43 metal-poor stars (Jonsell+, 2005) Authors: Jonsell, K.; Edvardsson, B.; Gustafsson, B.; Magain, P.; Nissen, P. E.; Asplund, M. Bibcode: 2005yCat..34400321J Altcode: Data from an analysis of 43 metal-poor field stars with iron abundances [Fe/H] ranging from -0.4 to -3.0dex are presented here. Photometric data, stellar velocities, masses, fundamental parameters, spectral classifications and notations of possible binarity are given. Tables with line data for O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe, Ni and Ba, equivalent widths and resulting abundances are also given.

(4 data files). Title: Abundance correlations in mildly metal-poor stars. II. Light elements (C to Ca) Authors: Decauwer, H.; Jehin, E.; Parmentier, G.; Magain, P. Bibcode: 2005A&A...433..285D Altcode: Accurate relative abundances have been obtained for carbon, oxygen, sodium, aluminium, silicon, and calcium in a sample of mildly metal-poor stars. This analysis complements a previous study carried out by Jehin et al. ([CITE], A&A, 341, 241), which provided the basis for the EASE scenario. This scenario postulates that field metal-poor stars were born in self-enriched proto-globular cluster clouds. By further investigating the correlations between the different α-element abundances, we propose a modified scenario for the formation of intermediate metallicity stars, in which the stars exhibiting lower than average α/Fe abundance ratios would form in low mass clouds, unable to sustain the formation of very massive stars (M ⪆ 30~M_⊙). Moreover, the carbon-to-iron ratio is found to decrease as one climbs the so-called Population IIb branch, i.e. when the s-element abundance increases. In the framework of the EASE scenario, we interpret this anticorrelation between the carbon and the s-element abundances as a signature of a hot bottom burning process in the metal-poor AGB stars which expelled the matter subsequently accreted by our Population IIb stars.

Based on observations collected at the European Southern Observatory, La Silla, Chile (ESO Programmes 56.E-0384, 57.E-0400 and 59.E-0257). Title: The Influence of Blends on the Potential of Extrasolar Planets Transit Surveys Authors: Gillon, M.; Magain, P.; Guillot, T.; Fressin, F. Bibcode: 2005prpl.conf.8151G Altcode: 2005LPICo1286.8151G No abstract at ADS Title: α-elements in mildly metal-poor stars Authors: Decauwer, H.; Jehin, E.; Parmentier, G.; Magain, P. Bibcode: 2005IAUS..228..393D Altcode: Accurate relative abundances of light elements (C to Ca) have been obtained in a sample of mildly metal-poor stars (Decauwer et al. 2005). Combined with the results of a previous study (Jehin et al. 1999), we find different slopes in the correlations between the different α-elements. These results can be explained by postulating that the stars exhibiting lower than average α/Fe form in low mass clouds, unable to sustain the formation of very massive stars. Title: Chemical abundances in 43 metal-poor stars Authors: Gustafsson, Bengt; Asplund, Martin; Edvardsson, Bengt; Jonsell, Karin; Magain, Pierre; Nissen, Poul Erik Bibcode: 2005IAUS..228..259G Altcode: We have derived abundances of O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe, Ni and Ba for 43 metal-poor field stars, mostly stars at the turn-off point and on the subgiant branch, in the interval {-}3.0{[Fe/H]{. The analysis is differential relative to the Sun. Oxygen abundances, with consideration of NLTE effects, were derived from the OI 777.4 nm triplet lines. We find [O/Fe] to gradually increase with decreasing [Fe/H], though considerably slower than has earlier been obtained from OH lines in the UV. A scatter in [O,Mg,Ca,Ti/Fe] at a given [Fe/H] is found and we argue that this scatter is partly real. The deviations from the mean trends of abundance ratios vs [Fe/H] are found to correlate in non-trivial ways for different abundances. Similar trends are found from results of accurate studies by other groups. This seems to give further evidence for the hypothesis that the stars once formed in different subsystems, with different star-formation rates.The paper is in press in A&A, may be obtained as astro-ph/0505118. Title: Abundance analysis of targets for the COROT/MONS asteroseismology missions. II. Abundance analysis of the COROT main targets Authors: Bruntt, H.; Bikmaev, I. F.; Catala, C.; Solano, E.; Gillon, M.; Magain, P.; Van't Veer-Menneret, C.; Stütz, C.; Weiss, W. W.; Ballereau, D.; Bouret, J. C.; Charpinet, S.; Hua, T.; Katz, D.; Lignières, F.; Lueftinger, T. Bibcode: 2004A&A...425..683B Altcode: 2004astro.ph..3464B One of the goals of the ground-based support program for the COROT and MONS/RÖMER satellite missions is to characterize suitable target stars for the part of the missions dedicated to asteroseismology. We present the detailed abundance analysis of nine of the potential COROT main targets using the semi-automatic software VWA. For two additional COROT targets we could not perform the analysis due to the high rotational velocity of these stars. For five stars with low rotational velocity we have also performed abundance analysis by a classical equivalent width method in order to test the reliability of the VWA software. The agreement between the different methods is good. We find that it is necessary to measure abundances extracted from each line relative to the abundances found from a spectrum of the Sun in order to remove systematic errors. We have constrained the global atmospheric parameters Teff, log g, and [Fe/H] to within 70-100 K, 0.1-0.2 dex, and 0.1 dex for five stars which are slow rotators (v sin i < 15 km s-1). For most of the stars we find good agreement with the parameters found from line depth ratios, H α lines, Strömgren indices, previous spectroscopic studies, and also log g determined from the HIPPARCOS parallaxes. For the fast rotators (v sin i > 60 km s-1) it is not possible to constrain the atmospheric parameters.

Based on observations obtained with the 193 cm telescope at Observatoire de Haute Provence, France. Title: On-axis spectroscopy of the z =0.144 radio-loud quasar HE 1434-1600: an elliptical host with a highly ionized ISM Authors: Letawe, G.; Courbin, F.; Magain, P.; Hilker, M.; Jablonka, P.; Jahnke, K.; Wisotzki, L. Bibcode: 2004A&A...424..455L Altcode: 2004astro.ph..5309L VLT on-axis optical spectroscopy of the z=0.144 radio-loud quasar HE 1434-1600 is presented. The spatially resolved spectra of the host galaxy are deconvolved and separated from those of the central quasar in order to study the dynamics of the stars and gas as well as the physical conditions of the ISM. We find that the host of HE 1434-1600 is an elliptical galaxy that resides in a group of at least 5 member galaxies, and that most likely experienced a recent collision with its nearest companion. Compared with other quasar host galaxies, HE 1434-1600 has a highly ionized ISM. The ionization state corresponds to that of typical Seyferts, but the ionized regions are not distributed in a homogeneous way around the QSO, and are located preferentially several kiloparsecs away from it. While the stellar absorption lines do not show any significant velocity field, the gas emission lines do. The observed gas velocity field is hard to reconcile with dynamical models involving rotating disk, modified Hubble laws or power laws, that all require extreme central masses (M>109 M⊙) to provide only poor fit to the data. Power law models, which best fit the data, provide a total mass of M(<10 kpc) = 9.2 × 1010 M⊙. We conclude that the recent interaction between HE 1434-1600 and its closest companion has strongly affected the gas velocity and ionization state, from the center of the galaxy to its most external parts.

Based on observations made with the ESO Very Large Telescope ANTU/UT1 at ESO-Paranal observatory, Chile (program 65.P-0361(A)). Title: Accretion of Gas by Globular Cluster Stars Authors: Thoul, A.; Jehin, E.; Magain, P.; Noels, A.; Parmentier, G.; Jorissen, A.; Goriely, S. Bibcode: 2003ASPC..296..315T Altcode: 2003nhgc.conf..315T No abstract at ADS Title: On-axis VLT spectroscopy of quasar host galaxies: HE 1503+0228, at z=0.135 Authors: Courbin, F.; Letawe, G.; Magain, P.; Wisotzki, L.; Jablonka, P.; Jahnke, K.; Kuhlbrodt, B.; Alloin, D.; Meylan, G. Bibcode: 2003ASPC..290..491C Altcode: 2003agnc.conf..491C No abstract at ADS Title: p-mode Oscillations of α Cen A Authors: Thoul, A.; Scuflaire, R.; Vatovez, B.; Noels, A.; Magain, P.; Briquet, M.; Dupret, M. -A. Bibcode: 2003Ap&SS.284..241T Altcode: Models of α Cen A & B have been computed using the masses determined by Pourbaix et al. (2002) and the data derived from the spectroscopic analysis of Neuforge and Magain (1997). The seismological data obtained by Bouchy and Carrier (2001, 2002) do help improve our knowledge of the evolutionary status of the system. All the constraints are satisfied with a model which gives an age of about 6 Gyr for the binary. Title: Variable Blue Stragglers and the EASE Scenario Authors: Noels, A.; Scuflaire, R.; Magain, P.; Parmentier, G.; Thoul, A. Bibcode: 2003aahd.conf..437N Altcode: No abstract at ADS Title: On-axis spatially resolved spectroscopy of low redshift quasar host galaxies: HE 1503+0228, at z=0.135 Authors: Courbin, F.; Letawe, G.; Magain, P.; Wisotzki, L.; Jablonka, P.; Jahnke, K.; Kuhlbrodt, B.; Alloin, D.; Meylan, G.; Minniti, D.; Burud, I. Bibcode: 2002A&A...394..863C Altcode: 2002astro.ph..8514C We present the first result of a comprehensive spectroscopic study of quasar host galaxies. On-axis, spatially resolved spectra of low redshift quasars have been obtained with FORS1, mounted on the 8.2 m ESO Very Large Telescope, Antu. The spectra are spatially deconvolved using a spectroscopic version of the ``MCS deconvolution algorithm''. The algorithm decomposes two dimensional spectra into the individual spectra of the central point-like nucleus and of its host galaxy. Applied to HE 1503+0228 at z=0.135 (MB=-23.0), it provides us with the spectrum of the host galaxy between 3600 Å and 8500 Å (rest-frame), at a mean resolving power of 700. The data allow us to measure several of the important Lick indices. The stellar populations and gas ionization state of the host galaxy of HE 1503+0228 are very similar to the ones measured for normal non-AGN galaxies. Dynamical information is also available for the gas and stellar components of the galaxy. Using deconvolution and a deprojection algorithm, velocity curves are derived for emission lines, from the center up to 4\arcsec away from the nucleus of the galaxy. Fitting a simple three-components mass model (point mass, spherical halo of dark matter, disk) to the position-velocity diagram, we infer a mass of M(r<1 kpc) = (2.0 +/- 0.3)x 1010 Msun within the central kiloparsec of the galaxy, and a mass integrated over 10 kpc of M(r<10 kpc) = (1.9 +/- 0.3) x 1011 Msun, with an additional 10% error due to the uncertainty on the inclination of the galaxy. This, in combination with the analysis of the stellar populations indicates that the host galaxy of HE 1503+0228, is a normal spiral galaxy. Based on observations made with ANTU/UT1 at ESO-Paranal observatory in Chile (program 65.P-0361(A)), and with the ESO 3.5 m NTT, at La Silla observatory (program 62.P-0643(B)). Title: Time delay and lens redshift for the doubly imaged BAL quasar SBS 1520+530 Authors: Burud, I.; Hjorth, J.; Courbin, F.; Cohen, J. G.; Magain, P.; Jaunsen, A. O.; Kaas, A. A.; Faure, C.; Letawe, G. Bibcode: 2002A&A...391..481B Altcode: 2002astro.ph..6084B We present optical R-band light curves of the gravitationally lensed quasar SBS 1520+530 derived from data obtained at the Nordic Optical Telescope. A time delay of 130+/-3 days (1sigma ) is determined from the light curves. In addition, spectra of SBS 1520+530 obtained at the Keck Observatory are spatially deconvolved in order to extract the spectrum of the faint lensing galaxy, free of any contamination by the light from the bright quasar images. This spectrum indicates a lens redshift z=0.717, in agreement with one of the absorption systems found in the quasar spectra. The best mass model of the system includes a second nearby galaxy and a cluster of galaxies in addition to the main lensing galaxy. Adopting this model and an Omega =0.3, Lambda =0.7 cosmology, our time-delay measurement yields a Hubble constant of H0=51 +/- 9 km s-1 Mpc-1 (1sigma error). Based on observations made with the Nordic Optical, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias and the W. M. Keck Observatory which is operated jointly by the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. Table 2 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/391/481 Title: VizieR Online Data Catalog: R-band photometry of SBS1520+530 (Burud+, 2002) Authors: Burud, I.; Hjorth, J.; Courbin, F.; Cohen, J. G.; Magain, P.; Jaunsen, A. O.; Kaas, A. A.; Faure, C.; Letawe, G. Bibcode: 2002yCat..33910481B Altcode: The table lists the data points obtained at the Nordic Optical Telescope used to derive the time delay for the lensed quasar QSO1520+530. (1 data file). Title: Spectroscopy of quasar host galaxies at the VLT: stellar populations and dynamics down to the central kiloparsec Authors: Courbin, F.; Letawe, G.; Magain, P.; Wisotzki, L.; Jablonka, P.; Alloin, D.; Jahnke, K.; Kuhlbrodt, B.; Meylan, G.; Minniti, D. Bibcode: 2002Msngr.107...28C Altcode: 1. Scientific Context 2. VLT Spectroscopic Observations 3. Spectra Decomposition and Stellar Population 4. Dynamics of the Host 5. Towards 2D Spectroscopy and High Spatial Resolution: GIRAFFE, SINFONI and FALCON Title: Accretion of gas by globular cluster stars Authors: Thoul, A.; Jorissen, A.; Goriely, S.; Jehin, E.; Magain, P.; Noels, A.; Parmentier, G. Bibcode: 2002A&A...383..491T Altcode: 2002astro.ph..1341T Some recent observations of the abundances of s-process, r-process, and alpha elements in metal-poor stars have led to a new scenario for their formation. According to this scenario, these stars were born in a globular cluster and accreted the s-process enriched gas expelled by cluster stars of higher-mass, thereby modifying their surface abundances. Later on, these polluted stars evaporated from the globular cluster to constitute an important fraction of the current halo population. In addition, there are now many direct observations of abundance anomalies not only in globular cluster giant stars but also in subgiant and main-sequence stars. Accretion again provides a plausible explanation for (at least some of) these peculiarities. Here we investigate further the efficiency of the accretion scenario. We find that in concentrated clusters with large escape velocities, accretion is very efficient and can indeed lead to major modifications of the stellar surface abundances. Title: Metallicity Gradients in Globular Cluster Systems : the Trace of a Self-Enrichment Process ? Authors: Parmentier, G.; Magain, P.; Noels, A.; Thoul, A.; Jehin, E. Bibcode: 2002IAUS..207..733P Altcode: We have developed a model of globular cluster self-enrichment, based on the ability of the globular cluster gaseous progenitors to retain the ejecta of a first generation of Type II Supernovae. The key point is that this ability depends on the pressure exerted on the progenitor cloud by the surrounding protogalactic medium and therefore on the location of the cloud in the protogalaxy. The model is able to explain the galactic halo metallicities and the metallicity gradient of the Old Halo which is thought to be the genuine galactic globular cluster system. The possibility that metallicity gradients are a common property of extragalactic globular cluster systems is also presented. Title: Evidence For a Self-Enrichment Process in Galactic Halo Globular Clusters Authors: Parmentier, G.; Jehin, E.; Magain, P.; Noels, A.; Thoul, A. Bibcode: 2002ASPC..285..234P Altcode: 2002msfo.conf..234P No abstract at ADS Title: An optical time-delay for the lensed BAL quasar HE 2149-2745 Authors: Burud, I.; Courbin, F.; Magain, P.; Lidman, C.; Hutsemékers, D.; Kneib, J. -P.; Hjorth, J.; Brewer, J.; Pompei, E.; Germany, L.; Pritchard, J.; Jaunsen, A. O.; Letawe, G.; Meylan, G. Bibcode: 2002A&A...383...71B Altcode: 2001astro.ph.12225B We present optical V and i-band light curves of the gravitationally lensed BAL quasar HE 2149-2745. The data, obtained with the 1.5 m Danish Telescope (ESO-La Silla) between October 1998 and December 2000, are the first from a long-term project aimed at monitoring selected lensed quasars in the Southern Hemisphere. A time delay of 103+/-12 days is determined from the light curves. In addition, VLT/FORS1 spectra of HE 2149-2745 are deconvolved in order to obtain the spectrum of the faint lensing galaxy, free of any contamination by the bright nearby two quasar images. By cross-correlating the spectrum with galaxy-templates we obtain a tentative redshift estimate of z=0.495+/-0.01. Adopting this redshift, a Omega =0.3, Lambda =0.7 cosmology, and a chosen analytical lens model, our time-delay measurement yields a Hubble constant of H0=66 +/- 8 km s-1 Mpc-1 (1sigma error) with an estimated systematic error of +/-3 km s-1 Mpc-1. Using non-parametric models yields H0=65 +/- 8 km s-1 Mpc-1 (1sigma error) and confirms that the lens exhibits a very dense/concentrated mass profile. Finally, we note, as in other cases, that the flux ratio between the two quasar components is wavelength dependent. While the flux ratio in the broad emission lines - equal to 3.7 - remains constant with wavelength, the continuum of the brighter component is bluer. Although the data do not rule out extinction of one quasar image relative to the other as a possible explanation, the effect could also be produced by differential microlensing by stars in the lensing galaxy. Based on observations made with the Danish 1.5-m telescope (ESO, La Silla, Chile) and at VLT UT1 Antu (ESO-Paranal, Chile) (Proposals: 64.O-0205(B), 65.O-0214(B), 66.A-0203(B), 67.A-0115(B), 66.B-0139(A) and HST archives ID 8175). Title: A novel approach for extracting time-delays from lightcurves of lensed quasar images Authors: Burud, I.; Magain, P.; Sohy, S.; Hjorth, J. Bibcode: 2001A&A...380..805B Altcode: 2001astro.ph.10668B We present a new method to estimate time delays from light curves of lensed quasars. The method is based on chi 2 minimization between the data and a numerical model light curve. A linear variation can be included in order to correct for slow long-term microlensing effects in one of the lensed images. An iterative version of the method can be applied in order to correct for higher-order microlensing effects. The method is tested on simulated light curves. When higher-order microlensing effects are present, the time delay is best constrained with the iterative method. Analysis of a published data set for the lensed double Q 0957+561 yields results in agreement with other published estimates. Title: Deconvolving Spectra: Near-IR Spectroscopy of the Lens and Source in HE 1104-1805 Authors: Courbin, F.; Lidman, C.; Meylan, G.; Magain, P. Bibcode: 2001ASPC..237...85C Altcode: 2001glrp.conf...85C No abstract at ADS Title: What Happens to the Gas in Globular Clusters? Authors: Thoul, A.; Jehin, E.; Magain, P.; Noels, A.; Parmentier, G. Bibcode: 2001ASPC..228..571T Altcode: 2001dscm.conf..571T No abstract at ADS Title: An Optical Time Delay Estimate for the Double Gravitational Lens System B1600+434 Authors: Burud, I.; Hjorth, J.; Jaunsen, A. O.; Andersen, M. I.; Korhonen, H.; Clasen, J. W.; Pelt, J.; Pijpers, F. P.; Magain, P.; Østensen, R. Bibcode: 2000ApJ...544..117B Altcode: 2000astro.ph..7136B We present optical I-band light curves of the gravitationally lensed double QSO B1600+434 from observations obtained at the Nordic Optical Telescope (NOT) between 1998 April and 1999 November. The photometry has been performed by simultaneous deconvolution of all the data frames, involving a numerical lens galaxy model. Four methods have been applied to determine the time delay between the two QSO components, giving a mean estimate of Δt=51+/-4 days (95% confidence level). This is the fourth optical time delay ever measured. Adopting a Ω=0.3, Λ=0 universe and using the mass model of Maller et al., this time delay estimate yields a Hubble parameter of H0=52+14-8 km s-1 Mpc-1 (95% confidence level), where the errors include time delay as well as model uncertainties. There are time-dependent offsets between the two (appropriately shifted) light curves that indicate the presence of external variations due to microlensing. Based on observations made with the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. Title: The Old Halo metallicity gradient: the trace of a self-enrichment process Authors: Parmentier, G.; Jehin, E.; Magain, P.; Noels, A.; Thoul, A. A. Bibcode: 2000A&A...363..526P Altcode: 2000astro.ph..9477P Based on a model of globular cluster self-enrichment published in a previous paper, we present an explanation for the metallicity gradient observed throughout the galactic Old Halo. Our self-enrichment model is based on the ability of globular cluster progenitor clouds to retain the ejecta of a first generation of Type II Supernovae. The key point is that this ability depends on the pressure exerted on the progenitor cloud by the surrounding protogalactic medium and therefore on the location of the cloud in the protoGalaxy. Since there is no significant (if any) metallicity gradient in the whole halo, we also present a review in favour of a galactic halo partly built via accretions and mergers of satellite systems. Some of them bear their own globular clusters and therefore ``contaminate'' the system of globular clusters formed ``in situ'', namely within the original potential well of the Galaxy. Therefore, the comparison between our self-enrichment model and the observational data should be limited to the genuine galactic globular clusters, the so-called Old Halo group. Title: Lensed quasars: a matter of resolution Authors: Courbin, F.; Lidman, C.; Burud, I.; Hjorth, J.; Magain, P.; Golse, G.; Castander, F. Bibcode: 2000Msngr.101...20C Altcode: 2000Msngr.101...17C The interest in studying lensed quasars amongst the astronomical community has always been somewhat fluctuating. Periods of great enthusiasm and of profound disappointment have regularly followed one another. Title: Exploring the gravitationally lensed system HE 1104-1805: near-IR spectroscopy Authors: Courbin, F.; Lidman, C.; Meylan, G.; Kneib, J. -P.; Magain, P. Bibcode: 2000A&A...360..853C Altcode: 2000astro.ph..6168C A new technique for the spatial deconvolution of spectra is applied to near-IR (0.95-2.50 μm) NTT/SOFI spectra of the lensed, radio-quiet quasar HE 1104-1805. The continuum of the lensing galaxy is revealed between 1.5 μm and 2.5 μm. Although the spectrum does not show strong emission features, it is used in combination with previous optical and IR photometry to infer a plausible redshift in the range 0.8 < z < 1.2. Modeling of the system shows that the lens is complex, probably composed of the red galaxy seen between the quasar images and a more extended component associated with a galaxy cluster with fairly low velocity dispersion (~ 575 km s-1). Unless more constrains can be put on the mass distribution of the cluster, e.g. from deep X-ray observations, HE 1104-1805 will not be a good system to determine H0. We stress that multiply imaged quasars with known time delays may prove more useful as tools for detecting dark mass in distant lenses than for determining cosmological parameters. The spectra of the two lensed images of the source are of great interest. They show no trace of reddening at the redshift of the lens nor at the redshift of the source. This supports the hypothesis of an elliptical lens. Additionally, the difference between the spectrum of the brightest component and that of a scaled version of the faintest component is a featureless continuum. Broad and narrow emission lines, including the FeII features, are perfectly subtracted. The very good quality of our spectrum makes it possible to fit precisely the optical Fe II feature, taking into account the underlying continuum over a wide wavelength range. HE 1104-1805 can be classified as a weak Fe II emitter. Finally, the slope of the continuum in the brightest image is steeper than the continuum in the faintest image and supports the finding by Wisotzki et al. (1993) that the brightest image is microlensed. This is particularly interesting in view of the new source reconstruction methods from multiwavelength photometric monitoring. While HE 1104- 1805 does not seem the best target for determining cosmological parameters, it is probably the second most interesting object after Q 2237+0305 (the Einstein cross), in terms of microlensing. Based on observations collected with the ESO New Technology Telescope (program 61.B-0413) Title: Resolved stellar populations of super-metal-rich star clusters in the bulge of M 31 Authors: Jablonka, P.; Courbin, F.; Meylan, G.; Sarajedini, A.; Bridges, T. J.; Magain, P. Bibcode: 2000A&A...359..131J Altcode: 2000astro.ph..5040J We have applied the MCS image deconvolution algorithm (Magain et al. 1998) to HST/WFPC2 V, I data of three M 31 bulge globular clusters (G170, G177, and G198) and control fields near each cluster. All three clusters are clearly detected, with an increase in stellar density with decreasing radius from the cluster centers; this is the first time that stars have been resolved in bulge clusters in the inner regions of another galaxy. From the RGB slopes of the clusters and the difference in I magnitude between the HB and the top of the RGB, we conclude that these three clusters all have roughly solar metallicity, in agreement with earlier integrated-light spectroscopic measurements. Our data support a picture whereby the M 31 bulge clusters and field stars were born from the same metal-rich gas, early in the galaxy formation. Title: Were the Old Halo globular clusters able to sustain a self-enrichment phase? Authors: Parmentier, Geneviève; Jehin, Emmanuel; Magain, Pierre; Noels, Arlette; Thoul, Anne Bibcode: 2000NewAR..44..351P Altcode: It has been argued for a long time that the self-enrichment process could not occur within proto-globular clouds because of the supernova energetics. We revisit this argument and demonstrate that it may not be true. Since not all the kinetic energy of Type II Supernovae is deposited as kinetic energy of the ISM, we suggest comparing the binding energy of the progenitor cloud to the kinetic energy of the ISM instead of the kinetic energy of the Type II Supernova ejecta. This criterion is used to study the disruptive ability of Type II Supernovae onto proto-globular clouds. It is found that the early chemical history of globular clusters is greatly influenced by the pressure exerted by the external medium on their progenitor clouds. Title: Observational Constraints on a Self-Enrichment Model in Galactic Halo Globular Clusters Authors: Parmentier, G.; Jehin, E.; Magain, P.; Noels, A.; Thoul, A. Bibcode: 2000ESASP.445..483P Altcode: 2000sfsl.conf..483P No abstract at ADS Title: A Method for Spatial Deconvolution of Spectra Authors: Courbin, F.; Magain, P.; Kirkove, M.; Sohy, S. Bibcode: 2000ApJ...529.1136C Altcode: 1999astro.ph..9109C A method for spatial deconvolution of spectra is presented. It follows the same fundamental principles as the ``MCS image deconvolution algorithm'' recently developed by Magain, Courbin, & Sohy and uses information contained in the spectrum of a reference point-spread function to spatially deconvolve spectra of very blended sources. An improved resolution rather than an infinite one is aimed at, overcoming the well-known problem of ``deconvolution artifacts.'' As in the MCS algorithm, the data are decomposed into a sum of analytical point sources and a numerically deconvolved background so that the spectrum of extended sources in the immediate vicinity of bright point sources may be accurately extracted and sharpened. The algorithm has been tested on simulated data including seeing variation as a function of wavelength and atmospheric refraction. It is shown that the spectra of severely blended point sources can be resolved while fully preserving the spectrophotometric properties of the data. Extended objects ``hidden'' by bright point sources (up to 4-5 mag brighter) can be accurately recovered as well, provided the data have a sufficiently high total signal-to-noise ratio (200-300 per spectral resolution element). Such spectra are relatively easy to obtain, even down to faint magnitudes, within a few hours of integration time with 10 m class telescopes. Title: POX 186: the ultracompact blue compact dwarf galaxy reveals its nature Authors: Doublier, V.; Kunth, D.; Courbin, F.; Magain, P. Bibcode: 2000A&A...353..887D Altcode: 1999astro.ph..2294D; 1999astro.ph..2294V High resolution, ground based R and I band observations of the ultra compact dwarf galaxy POX 186 are presented. The data, obtained with the ESO New Technology Telescope (NTT), are analyzed using a new deconvolution algorithm which allows one to resolve the innermost regions of this stellar-like object into three Super-Star Clusters (SSC). Upper limits to both masses (M ~ 105 Msun) and physical sizes (<=60pc) of the SSCs are set. In addition, and maybe most importantly, extended light emission underlying the compact star-forming region is clearly detected in both bands. The R-I color rules out nebular Hα contamination and is consistent with an old stellar population. This casts doubt on the hypothesis that Blue Compact Dwarf Galaxies (BCDG) are young galaxies. based on observations carried out at NTT in La Silla, operated by the European Southern Observatory, during Director's Discretionary Time. Title: Abundance correlations in thick disk and halo stars Authors: Jehin, E.; Magain, P.; Noels, A.; Parmentier, G.; Thoul, A. Bibcode: 2000LIACo..35..151J Altcode: 2000ghgc.conf..151J No abstract at ADS Title: On the possibility of self-enrichement in globular clusters Authors: Parmentier, G.; Jehin, E.; Magain, P.; Neuforge, C.; Noels, A.; Thoul, A. A. Bibcode: 2000LIACo..35..561P Altcode: 2000ghgc.conf..561P No abstract at ADS Title: Puzzling locations of mildly metal-poor stars in the HR diagram Authors: Jehin, E.; Noels, A.; Magain, P.; Parmentier, G.; Thoul, A. Bibcode: 2000LIACo..35..231J Altcode: 2000ghgc.conf..231J No abstract at ADS Title: The metallicity gradient of the old halo Authors: Parmentier, G.; Jehin, E.; Magain, P.; Noels, A.; Thoul, A. Bibcode: 2000LIACo..35..623P Altcode: 2000ghgc.conf..623P No abstract at ADS Title: Accretion from AGB winds. Authors: Thoul, A.; Jorissen, A.; Goriely, S.; Jehin, E.; Magain, P.; Noels, A.; Parmentier, G. Bibcode: 2000MmSAI..71..791T Altcode: No abstract at ADS Title: The EASE Scenario: Dynamical Study of the Supernova Phase Authors: Parmentier, Geneviève; Jehin, Emannuel; Magain, Pierre; Noels, Arlette; Thoul, Anne Bibcode: 2000fist.conf..199P Altcode: We revisit the most often encountered argument against self-enrichment in globular clusters, namely the ability of a few number of supernovae to disrupt the proto-globular cloud. We show that, within the context of the Fall and Rees theory, primordial proto-globular cluster clouds may sustain several hundreds of Type II supernovae. Furthermore, the corresponding self-enrichment level is in agreement with galactic halo globular cluster metallicities. Title: The Galactic Halo : from Globular Clusters to Field Stars Authors: Noels, A.; Magain, P.; Caro, D.; Jehin, E.; Parmentier, G.; Thoul, A. A. Bibcode: 2000LIACo..35.....N Altcode: 2000ghgc.conf.....N The following topics were dealt with: early galactic nucleosynthesis; chemical composition of metal-poor stars; metal-poor components of our Galaxy; HR diagrams of globular clusters; chemical and dynamical evolution of globular clusters. Title: Accretion processes onto globular cluster stars Authors: Thoul, A.; Jorissen, A.; Goriely, S.; Jehin, E.; Magain, P.; Noels, A.; Parmentier, G. Bibcode: 2000LIACo..35..567T Altcode: 2000ghgc.conf..567T No abstract at ADS Title: What Happens to the Gas in Globular Clusters? Authors: Thoul, A.; Jehin, E.; Magain, P.; Noels, A.; Parmentier, G. Bibcode: 2000AGM....16..P86T Altcode: Observations of globular clusters show that they contain much too little gas or dust, compared to what should be present due to the mass-losing stars in the cluster. Many authors have been intrigued by the fate of the gas in globular clusters. They have suggested various mechanisms by which the gas could escape from the cluster, such as stellar UV radiation, cluster winds driven by X-ray bursters, novae, or flare-stars, relativistic winds from millisecond pulsars, condensation into stars, accretion processes drawing upon a central gas reservoir, continuous sweeping of the cluster gas by the gaseous medium of the Galactic halo dots. Recent results also show that globular cluster stars show many abundance anomalies. Accretion of interstellar gas by the cluster stars has been suggested as a plausible mechanism to explain these anomalies. It is also a major ingredient of the EASE scenario linking halo field stars to globular clusters, which we have recently developed to explain strong r-and s-elements correlations in halo field dwarf stars. Here we will briefly review the status of gas and dust detection in globular clusters, as well as the possible gas removal mechanisms. We will explore in more details the gas and dust accretion processes onto main sequence stars. In particular, we will study the efficiency of this mechanism in removing gas from the globular clusters interstellar medium. Title: The Galactic halo. From globular clusters to field stars. Proceedings. Authors: Noels, A.; Magain, P.; Caro, D.; Jehin, E.; Parmentier, G.; Thoul, A. Bibcode: 2000ghfg.book.....N Altcode: The following topics were dealt with: early galactic nucleosynthesis; chemical composition of metal-poor stars; metal-poor components of our Galaxy; HR diagrams of globular clusters; chemical and dynamical evolution of globular clusters. Title: The EASE Scenario: A New Origin for Metal-Poor Stars? Authors: Jehin, Emmanuel; Magain, Pierre; Noels, Arlette; Parmentier, Geneviève; Thoul, Anne Bibcode: 2000fist.conf..204J Altcode: We have analysed high resolution and high signal-to-noise spectra of 21 mildly metal-poor stars. The correlations between the relative abundances of 16 elements have been studied, with a special emphasis on the neutron-capture ones. This analysis reveals the existence of two sub-populations of field metal-poor stars which differ by the behaviour of the s-process elements versus the α and r-process elements. We suggest a scenario for the formation of metal-poor stars, which closely relates the origin of these stars to the evolution of globular clusters. Title: Deep Imaging of AX J2019+112: The Luminosity of a ``Dark Cluster'' Authors: Benítez, Narciso; Broadhurst, Tom; Rosati, Piero; Courbin, Fred; Squires, Gordon; Lidman, Chris; Magain, Pierre Bibcode: 1999ApJ...527...31B Altcode: 1998astro.ph.12218B We detect a distant cluster of galaxies centered on the QSO lens and luminous X-ray source AX J2019+112, a.k.a. the ``Dark Cluster.'' Using deep V and I Keck images and wide-field Ks imaging from the New Technology Telescope (NTT), a tight red sequence of galaxies is identified within a radius of 0.2 h-1 Mpc of the known z=1.01 elliptical lensing galaxy. The sequence, which includes the central elliptical galaxy, has a slope in good agreement with the model predictions of Kodama et al. for z~1. We estimate the integrated rest-frame luminosity of the cluster to be LV>=3.2×1011 h-2 Lsolar (after accounting for significant extinction at the low latitude of this field), more than an order of magnitude higher than previous estimates. The central region of the cluster is deconvolved using the technique of Magain, Courbin, & Sohy, revealing a thick central arc coincident with an extended radio source. All the observed lensing features are readily explained by differential magnification of a radio-loud active galactic nucleus by a shallow elliptical potential. The QSO must lie just outside the diamond caustic, producing two images; the arc is a highly magnified image formed from a region close to the center of the host galaxy, projecting inside the caustic. The mass-to-light ratio within an aperture of 0.4 h-1 Mpc is MX/LV=224+112-78h(M/LV)solar, using the X-ray temperature. The strong lens model yields a compatible value, M/LV=372+94-94h(M/LV)solar, whereas an independent weak-lensing analysis sets an upper limit of M/LV<520h(M/LV)solar, typical of massive clusters.

Based on observations collected at the European Southern Observatory, La Silla, Chile, proposal number 61.A-0676. Title: The self-enrichment of galactic halo globular clusters. A clue to their formation? Authors: Parmentier, G.; Jehin, E.; Magain, P.; Neuforge, C.; Noels, A.; Thoul, A. A. Bibcode: 1999A&A...352..138P Altcode: 1999astro.ph.11258P We present a model of globular cluster self-enrichment. In the protogalaxy, cold and dense clouds embedded in the hot protogalactic medium are assumed to be the progenitors of galactic halo globular clusters. The massive stars of a first generation of metal-free stars, born in the central areas of the proto-globular cluster clouds, explode as Type II supernovae. The associated blast waves trigger the expansion of a supershell, sweeping all the material of the cloud, and the heavy elements released by these massive stars enrich the supershell. A second generation of stars is born in these compressed and enriched layers of gas. These stars can recollapse and form a globular cluster. This work aims at revising the most often encountered argument against self-enrichment, namely the presumed ability of a small number of supernovae to disrupt a proto-globular cluster cloud. We describe a model of the dynamics of the supershell and of its progressive chemical enrichment. We show that the minimal mass of the primordial cluster cloud required to avoid disruption by several tens of Type II supernovae is compatible with the masses usually assumed for proto-globular cluster clouds. Furthermore, the corresponding self-enrichment level is in agreement with halo globular cluster metallicities. Title: Deconvolving spectra of lensing galaxies, QSO hosts, and more ... Authors: Courbin, F.; Magain, P.; Sohy, S.; Lidman, C.; Meylan, G. Bibcode: 1999Msngr..97...26C Altcode: High spatial resolution undoubtedly plays a key role in most major advances in observational astrophysics. In this context, considerable effort has been devoted to the development of numerical methods aimed at improving the spatial resolution of astronomical images. However, the most commonly used techniques (e.g., Richardson 1972, Lucy 1974, Skilling & Bryan 1984) tend to produce the so-called “deconvolution artefacts” (oscillations in the vicinity of high spatial frequency structures) which alter the photometric and astrometric properties of the original data. Recently, Magain, Courbin & Sohy (1998ab; hereafter MCS) proposed and implemented a new deconvolution algorithm which overcomes such drawbacks. Its success is mainly the consequence of a deliberate choice to achieve an improved resolution rather than an infinite one, hence avoiding retrieving spatial frequencies forbidden by the sampling theorem. Title: Linking Field Metal-Poor Stars and Globular Clusters: the Ease Scenario Authors: Jehin, E.; Magain, P.; Neuforge, C.; Noels, A.; Parmentier, G.; Thoul, A. Bibcode: 1999Ap&SS.265..287J Altcode: No abstract at ADS Title: About the origin of extinction in the gravitational lens system MG J0414+0534 Authors: Angonin-Willaime, M. -C.; Vanderriest, C.; Courbin, F.; Burud, I.; Magain, P.; Rigaut, F. Bibcode: 1999A&A...347..434A Altcode: Photometric measurements of the highly reddened gravitational mirage MG J0414+0534 have been carried out either by PSF subtraction or by applying accurate deconvolution algorithms to optical (R, I) and near-infrared (K) images obtained at CFHT and NOT under sub-arcsecond seeing conditions. It is confirmed that the close pair of images A1-A2 suffers a larger extinction than B and C. While the colours of image A2 obtained from ground-based data seem inconsistent with a simple reddening law, higher resolution images available from HST archives reveal an additional extended component (arc) which introduces significant errors in the photometric decomposition. When the arc component is properly taken into account, the colours of the 4 nucleus images do agree with a classical reddening law, with A2 being by far the most obscured component. Such a differential extinction (maximum difference Delta E(R-I) =~ 0.6) is likely due to the lensing galaxy. This does not mean that {all} the extinction occurs into the lens. Indeed, the fact that the arc is much less red than the images of the nucleus suggests that an important part of the reddening is intrinsic to the source. Finally, no significant variability is observed within this data set, i.e. between 1994 and 1997, while a discrepancy from earlier data is noticed for (A1 + A2). Based on observations collected with the Canada-France-Hawaii Telescope at Mauna Kea (Hawaii, USA), the Nordic Optical Telescope (Canary, Spain) and archive data from the Hubble Space Telescope (NASA/ESA) Title: BIMA and Keck Imaging of the Radio Ring PKS 1830-211 Authors: Frye, B. L.; Courbin, F.; Broadhurst, T. J.; Welch, W. J. W.; Lidman, C.; Magain, P.; Pahre, M.; Djorgovski, S. G. Bibcode: 1999ASPC..156..240F Altcode: 1998astro.ph..2347F; 1999hrrl.conf..240F We discuss BIMA (Berkeley Illinois Maryland Association) data and present new h igh quality optical and near-IR Keck images of the bright radio ring PKS 1830-211. Applying a powerful new deconvolution algorithm we have been able to identify both images of the radio source. In addition we recover an extended source in the optical, consistent with the expected location of the lensing galaxy. The source counterparts are very red, I-K ~7 suggesting strong Galactic absorption with additional absorption by the lensing galaxy at z = 0.885, and consistent with the detection of high redshift molecules in the lens. Title: Abundance correlations in mildly metal-poor stars Authors: Jehin, E.; Magain, P.; Neuforge, C.; Noels, A.; Parmentier, G.; Thoul, A. A. Bibcode: 1999A&A...341..241J Altcode: 1998astro.ph..9405J Accurate relative abundances have been obtained for a sample of 21 mildly metal-poor stars from the analysis of high resolution and high signal-to-noise spectra. In order to reach the highest coherence and internal precision, lines with similar dependency on the stellar atmospheric parameters were selected, and the analysis was carried out in a strictly differential way within the sample. With these accurate results, correlations between relative abundances have been searched for, with a special emphasis on the neutron capture elements. This analysis shows that the r elements are closely correlated to the alpha elements, which is in agreement with the generally accepted idea that the r-process takes place during the explosion of massive stars. The situation is more complex as far as the s elements are concerned. Their relation with the alpha elements is not linear. In a first group of stars, the relative abundance of the s elements increases only slightly with the alpha elements overabundance until the latter reaches a maximum value. For the second group, the s elements show a rather large range of enhancement and a constant (and maximum) value of the alpha elements overabundance. This peculiar behaviour leads us to distinguish between two sub-populations of metal-poor stars, namely Pop IIa (first group) and Pop IIb (second group). We suggest a scenario of formation of metal-poor stars based on two distinct phases of chemical enrichment, a first phase essentially consisting in supernova explosions of massive stars, and a second phase where the enrichment is provided by stellar winds from intermediate mass stars. More specifically, we assume that all thick disk and field halo stars were born in globular clusters, from which they escaped, either during an early disruption of the cluster (Pop IIa) or, later, through an evaporation process (Pop IIb). Based on observations obtained at the European Southern Observatory, La Silla, Chile. Title: Image deconvolution of lensed QSOs observed with the NOT: Competing with the HST (poster) Authors: Burud, I.; Courbin, F.; Magain, P. Bibcode: 1999anot.conf..105B Altcode: No abstract at ADS Title: Linking Field Metal-Poor Stars and Globular Clusters: The Ease Scenario Authors: Jehin, E.; Magain, P.; Neuforge, C.; Noels, A.; Parmentier, G.; Thoul, A. Bibcode: 1999gecd.conf..287J Altcode: No abstract at ADS Title: Deep imaging of AXJ2019+112: The luminosity of a ``Dark Cluster'' Authors: Benitez, N.; Broadhurst, T.; Rosati, P.; Courbin, F.; Squires, G.; Lidman, C.; Magain, P. Bibcode: 1998tx19.confE.504B Altcode: We detect a distant cluster of galaxies at z ~1 centered on the QSO lens and luminous X-ray source AXJ2019+112 (Hattori et al 1997). The mass-to-light ratio within an aperture of 0.4 h ^{-1}Mpc determined using the X-ray temperature is M_x / L_V = 190^{+95}_{-66}h(M/L_V)sun. The strong lens model yields a compatible value, M/L_V = 315^{+80}_{-80}h(M/L_V)sun, whereas an independent weak lensing analysis sets an upper limit of M/L_V < 440 h(M/L_V)sun. This confirms that AXJ2019+112 has a M/L ratio similar to that of z < 1 massive clusters. Title: Three photometric methods tested on ground-based data of Q 2237+0305 Authors: Burud, I.; Stabell, R.; Magain, P.; Courbin, F.; Ostensen, R.; Refsdal, S.; Remy, M.; Teuber, J. Bibcode: 1998A&A...339..701B Altcode: 1998astro.ph..9107B The Einstein Cross, Q 2237+0305, has been photometrically observed in four bands on two successive nights at NOT (La Palma, Spain) in October 1995. Three independent algorithms have been used to analyse the data: an automatic image decomposition technique, a CLEAN algorithm and the new MCS deconvolution code. The photometric and astrometric results obtained with the three methods are presented. No photometric variations were found in the four quasar images. Comparison of the photometry from the three techniques shows that both systematic and random errors affect each method. When the seeing is worse than 1farcs0 , the errors from the automatic image decomposition technique and the Clean algorithm tend to be large (0.04-0.1 magnitudes) while the deconvolution code still gives accurate results (1sigma error below 0.04) even for frames with seeing as bad as 1farcs7 . Reddening is observed in the quasar images and is found to be compatible with either extinction from the lensing galaxy or colour dependent microlensing. The photometric accuracy depends on the light distribution used to model the lensing galaxy. In particular, using a numerical galaxy model, as done with the MCS algorithm, makes the method less seeing dependent. Another advantage of using a numerical model is that eventual non-homogeneous structures in the galaxy can be modeled. Finally, we propose an observational strategy for a future photometric monitoring of the Einstein Cross. Based on observations obtained at NOT, La Palma. Title: High-Resolution Optical and Near-Infrared Imaging of the Quadruple Quasar RX J0911.4+0551 Authors: Burud, I.; Courbin, F.; Lidman, C.; Jaunsen, A. O.; Hjorth, J.; Østensen, R.; Andersen, M. I.; Clasen, J. W.; Wucknitz, O.; Meylan, G.; Magain, P.; Stabell, R.; Refsdal, S. Bibcode: 1998ApJ...501L...5B Altcode: 1998astro.ph..3175B We report the detection of four images in the recently discovered lensed QSO RX J0911.4+0551. With a maximum angular separation of 3.1", it is the quadruply imaged QSO with the widest known angular separation. Raw and deconvolved data reveal an elongated lens galaxy. The observed reddening in at least two of the four QSO images suggests differential extinction by this lensing galaxy. We show that both an ellipticity of the galaxy (ɛmin=0.075) and an external shear (γmin=0.15) from a nearby mass have to be included in the lensing potential in order to reproduce the complex geometry observed in RX J0911.4+0551. A possible galaxy cluster is detected about 38" from RX J0911.4+0551 and could contribute to the X-ray emission observed by ROSAT in this field. The color of these galaxies indicates a plausible redshift in the range of 0.6-0.8.

Based on observations obtained at NOT and ESO La Silla. Title: Image Deconvolution of the Radio Ring PKS 1830-211 Authors: Courbin, F.; Lidman, C.; Frye, B. L.; Magain, P.; Broadhurst, T. J.; Pahre, M. A.; Djorgovski, S. G. Bibcode: 1998ApJ...499L.119C Altcode: 1998astro.ph..2156C New high-quality Keck and ESO images of PKS 1830-211 are presented. By applying a powerful new deconvolution algorithm to these optical and infrared data, both images of the flat spectrum core of the radio source have been identified. An extended source is also detected in the optical images which is consistent with the expected location of the lensing galaxy. The source counterparts are very red at I-K~7, which suggests strong Galactic absorption with additional absorption by the lensing galaxy at z=0.885 and is consistent with the detection of high-redshift molecules in the lens.

Based on observations obtained at the ESO La Silla Observatory, Chile and at the W. M. Keck Observatory, Hawaii, which is operated jointly by the California Institute of Technology and the University of California. Title: RX J0911.4+0551: a complex quadruply imaged gravitationally lensed QSO. Authors: Burud, I.; Courbin, F.; Lidman, C.; Meylan, G.; Magain, P.; Jaunsen, A. O.; Hjorth, J.; Østensen, R.; Andersen, M. I.; Clasen, J. W.; Stabell, R.; Refsdal, S. Bibcode: 1998Msngr..92...29B Altcode: The authors present their first observations of RX J0911.4+0551 at the 2.2-m ESO/MPI IRAC 2b in K-band which made them suspect that the QSO might be quadruple. This was confirmed on the optical data from the 2.56-m Nordic Optical Telescope, and on the NTT/SOFI data of the object. Careful deconvolution of the data allows to clearly resolve the object into four QSO components and a lensing galaxy. Title: Deconvolution with Correct Sampling Authors: Magain, P.; Courbin, F.; Sohy, S. Bibcode: 1998ApJ...494..472M Altcode: 1997astro.ph..4059M A new method for improving the resolution of astronomical images is presented. It is based on the principle that sampled data cannot be fully deconvolved without violating the sampling theorem. Thus, the sampled image should be deconvolved not by the total point-spread function but by a narrower function chosen so that the resolution of the deconvolved image is compatible with the adopted sampling.

Our deconvolution method gives results that are, in at least some cases, superior to those of other commonly used techniques: in particular, it does not produce ringing around point sources superposed on a smooth background. Moreover, it allows researchers to perform accurate astrometry and photometry of crowded fields. These improvements are a consequence of both the correct treatment of sampling and the recognition that the most probable astronomical image is not a flat one.

The method is also well adapted to the optimal combination of different images of the same object, as can be obtained, e.g., from infrared observations or via adaptive optics techniques. Title: Heavy elements abundances in metal-poor stars Authors: Magain, P.; Jehin, E.; Neuforge, C.; Noels, A. Bibcode: 1998AIPC..425..592M Altcode: A sample of 21 metal-poor stars have been analysed on the basis of high resolution and high signal-to-noise spectra. Correlations between relative abundances of 16 elements have been studied, with a special emphasis on the neutron-capture ones. This analysis reveals the existence of two sub-populations of field halo stars, namely Pop IIa and Pop IIb. They differ by the behaviour of the s-process elements versus the α and r-process elements. We suggest a scenario of formation of these stars, which closely relates the field halo stars to the evolution of globular clusters. The two sub-populations would have evaporated the clusters during two different stages of their chemical evolution. Title: Detection of the lensing galaxy in HE 1104-1805 Authors: Courbin, F.; Lidman, C.; Magain, P. Bibcode: 1998A&A...330...57C Altcode: 1997astro.ph..7183C We report on deep IR imaging of the double quasar HE 1104-1805. A new image deconvolution technique has been applied to the data in order to optimally combine the numerous frames obtained. The resulting J and K' images allow us to detect and study the lensing galaxy between the two lensed QSO images. The near infrared images not only confirm the lensed nature of this double quasar, but also support the previous redshift estimate of z=1.66 for the lensing galaxy. No obvious overdensity of galaxies is detected in the immediate region surrounding the lens, down to limiting magnitudes of J=22 and K=20. The geometry of the system, together with the time delays expected for this lensed quasar, make HE 1104-1805 a remarkable target for future photometric monitoring programs, for the study of microlensing and for the determination of the cosmological parameters in the IR and optical domains. Based on observations obtained at ESO, La Silla, Chile Title: Field halo stars: the globular cluster connection Authors: Jehin, E.; Magain, P.; Neuforge, C.; Noels, A.; Thoul, A. A. Bibcode: 1998A&A...330L..33J Altcode: High resolution and high signal-to-noise spectra of about 20 metal-poor stars have been analysed. The correlations between the relative abundances of 16 elements have been studied, with a special emphasis on the neutron-capture ones. This analysis reveals the existence of two subpopulations of field halo stars, namely Pop IIa and Pop IIb. They differ by the behaviour of the s-process elements versus the alpha and r-process elements. A scenario for the formation of these stars is presented, which closely relates the origin of field halo stars to the evolution of globular clusters. According to this scenario, the two sub-populations originate from two different stages in the globular cluster's chemical evolution. Based on observations carried out at the European Southern Observatory (La Silla, Chile) Title: The impact of AGB stars on the chemical evolution of globular clusters Authors: Jehin, E.; Magain, P.; Neuforge, C.; Noels, A.; Parmentier, G.; Thoul, A. A. Bibcode: 1998IAUS..191P.603J Altcode: We have analyzed high resolution and high signal-to-noise spectra of about 20 metal-poor stars. The correlations between the relative abundances of 16 elements have been studied, with a special emphasis on the neutron-capture ones. This analysis reveals the existence of two sub-populations of field halo stars, namely Pop IIa and Pop IIb. They differ by the behaviour of the s-process elements versus the alpha and r-process elements. We present a scenario for the formation of these stars, which closely relates the origin of field halo stars to the evolution of globular clusters. According to this scenario, the two sub-populations originate from two different stages in the globular cluster's chemical evolution. In the first stage, the massive stars of the globular cluster's first stellar generation evolve, ending their lives as supernovae and ejecting alpha-elements and r-process elements into the interstellar medium. A second generation of stars forms out of this enriched ISM. In the second stage, the intermediate mass stars reach the end of the main sequence and the AGB stage, ejecting s-elements into the ISM through stellar winds or superwinds events. The matter released in the ISM by the AGB stars will be accreted by the lower-mass stars, enriching those stars in s-elements and accounting for PopIIb stars. We calculate the rates of interstellar gas production by stellar winds and the rates of gas accretion to estimate the changes in the globular cluster stars abundances. We compare those results to our observations. Title: ESO & NOT photometric monitoring of the Cloverleaf quasar Authors: Ostensen, R.; Remy, M.; Lindblad, P. O.; Refsdal, S.; Stabell, R.; Surdej, J.; Barthel, P. D.; Emanuelsen, P. I.; Festin, L.; Gosset, E.; Hainaut, O.; Hakala, P.; Hjelm, M.; Hjorth, J.; Hutsemekers, D.; Jablonski, M.; Kaas, A. A.; Kristen, H.; Larsson, S.; Magain, P.; Pettersson, B.; Pospieszalska-Surdej, A.; Smette, A.; Teuber, J.; Thomsen, B.; van Drom, E. Bibcode: 1997A&AS..126..393O Altcode: The Cloverleaf quasar, H1413+117, has been photometrically monitored at ESO (La Silla, Chile) and with the NOT (La Palma, Spain) during the period 1987--1994. All good quality CCD frames have been successfully analysed using two independent methods (i.e. an automatic image decomposition technique and an interactive CLEAN algorithm). The photometric results from the two methods are found to be very similar, and they show that the four lensed QSO images vary significantly in brightness (by up to 0.45 mag), nearly in parallel. The lightcurve of the $D$ component presents some slight departures from the general trend which are very likely caused by micro-lensing effects. Upper limits, at the 99% confidence level, of 150 days on the absolute value for the time delays between the photometric lightcurves of this quadruply imaged variable QSO, are derived. This is unfortunately too large to constrain the lens model but there is little doubt that a better sampling of the lightcurves should allow to accurately derive these time delays. Pending a direct detection of the lensing galaxy (position and redshift), this system thus constitutes another good candidate for a direct and independent determination of the Hubble parameter. Based on observations collected at the European Southern Observatory (La Silla, Chile) and with the Nordic Optical Telescope (La Palma, Spain). Table 1. Logbook for the ESO and NOT observations together with photometric results for the Cloverleaf quasar. This long table can be accessed on the WWW at the URL address: http://vela.astro.ulg.ac.be/grav_lens/glp_homepage.html} Title: Spectroscopic analysis of the Alpha Centauri system Authors: Neuforge-Verheecke, C.; Magain, P. Bibcode: 1997A&A...328..261N Altcode: A detailed spectroscopic analysis of the two components of the binary system alpha Centauri has been carried out on the basis of extensive high resolution and high signal-to-noise spectra. The temperatures of the stars have been determined from the Fei excitation equilibrium and checked from the H_α line wings. The abundances of 17 elements have been obtained and indicate a general overabundance of 0.24 dex relative to the Sun, with no significant difference between the two stars. All elements analysed, from CNO to the iron peak, show basically the same overabundance. Only nickel seems to be significantly more overabundant, while the neutron capture elements appear less enhanced. Based on observations carried out at the European Southern Observatory (La Silla, Chile) Title: The LMC transition star R 84 and the core of the LH 39 OB association. Authors: Heydari-Malayeri, M.; Courbin, F.; Rauw, G.; Esslinger, O.; Magain, P. Bibcode: 1997A&A...326..143H Altcode: 1997astro.ph..6052H On the basis of sub-arcsecond imaging obtained at the ESO NTT with SUSI and the ESO ADONIS adaptive optics system at the 3.6m telescope, we resolve and study the core components of the LMC OB association LH 39. The central star of the association, the rare transition object R 84, is also investigated using CASPEC echelle spectroscopy at the ESO 3.6m telescope. A new, powerful image restoration code that conserves the fluxes allows us to obtain the magnitudes and colors of the components. We bring out some 30 stars in a ~16"x16" area centered on R 84. At a resolution of 0.19"(FWHM), the closest components to R 84 are shown to be stars #21 and #7 lying at 1.1"NW and 1.7"NW respectively of the transition star. The former is possibly a blue star of V=16.7mag and the latter with its V=17.5mag is the reddest star of the field, after R 84. Star #7 turns out to be too faint to correspond to the red M2 supergiant previously reported to contaminate the spectrum of R 84. If the late-type spectrum is due to a line-of-sight supergiant with a luminosity comparable to R 84, it should lie closer than 0.12" to R 84. The transition star shows spectral variability between 1982 and 1991. We also note some slight radial velocity variations of the Of emission lines over timescales of several years. Furthermore, we derive the spectral types of two of the brightest stars of the cluster, using long slit spectra obtained at the NTT telescope equipped with EMMI, and discuss the apparent absence of O type stars in this association. Title: The geometry of the quadruply imaged quasar PG 1115+080: implications for H_0_. Authors: Courbin, F.; Magain, P.; Keeton, C. R.; Kochanek, C. S.; Vanderriest, C.; Jaunsen, A. O.; Hjorth, J. Bibcode: 1997A&A...324L...1C Altcode: 1997astro.ph..5093C Time delay measurements have recently been reported for the lensed quasar PG 1115+080. These measurements can be used to derive H_0_, but only if we can constrain the lensing potential. We have applied a recently developed deconvolution technique to analyze sub-arcsecond I band images of PG 1115+080, obtained at the Nordic Optical Telescope (NOT) and the Canada France Hawaii Telescope (CFHT). The high performance of the deconvolution code allows us to derive precise positions and magnitudes for the four lensed images of the quasar, as well as for the lensing galaxy. The new measurement of the galaxy position improves its precision by a factor of 3 and thus strengthens the constraints on the lensing potential. With the new data, a range of models incorporating some of the plausible systematic uncertainties yields H_0_=53^+10^_-7_km/s/Mpc. Title: VizieR Online Data Catalog: Spectroscopy of Alpha Cen (Neuforge-Verheecke+ 1997) Authors: Neuforge-Verheecke, C.; Magain, P. Bibcode: 1997yCat..33280261N Altcode: This table presents the results of a spectroscopic analysis (differentially to the Sun) of the two components of the binary system Alpha Centauri. This analysis has been carried out on the basis of extensive high resolution and high signal-to-noise spectra taken at the European Southern Observatory (La Silla, Chile). (1 data file). Title: Deconvolution with correct sampling. Authors: Magain, P.; Courbin, F.; Sohy, S. Bibcode: 1997Msngr..88...28M Altcode: The authors briefly describe the basic ideas behind a new deconvolution technique which overcomes some of the drawbacks of the traditional methods and which gives results of high photometric and astrometric accuracy. The authors also show how it can be combined with other techniques (e.g. adaptive optics) to give even better results. Title: Sub-arcsecond imaging and spectroscopy of the radio-loud highly polarized quasar PKS 1610-771. Authors: Courbin, F.; Hutsemekers, D.; Meylan, G.; Magain, P.; Djorgovski, S. G. Bibcode: 1997A&A...317..656C Altcode: 1996astro.ph..6114C We report on imaging and spectroscopic observations of the radio-loud, highly polarized quasar PKS 1610-771 (z=1.71). Our long-slit spectroscopy of the companion 4.55" NW of the quasar confirms the stellar nature of this object, so ruling out the previously suspected gravitationally lensed nature of this system. PKS 1610-771 looks fuzzy on our sub-arcsecond R and I images and appears located in a rich environment of faint galaxies. Possible magnification, without image splitting of the quasar itself, by some of these maybe foreground galaxies cannot be excluded. The continuum fuzz (made of the closest two objects, viz. A and D) is elongated in a direction orthogonal to the E vector of the optical polarization, as in high-redshift radio-galaxies. The spectrum of PKS 1610-771 appears strongly curved, in a convex way, with a maximum of intensity at ~7,600Å (2,800AÅ rest frame), possibly indicating a strong ultraviolet absorption by dust. Title: PKS 1610-771: a highly reddened quasar? Authors: Courbin, F.; Hutsemékers, D.; Meylan, G.; Magain, P.; Djorgovski, S. G. Bibcode: 1996Msngr..85...27C Altcode: No abstract at ADS Title: WR22: the most massive Wolf-Rayet star ever weighed. Authors: Rauw, G.; Vreux, J. -M.; Gosset, E.; Hutsemekers, D.; Magain, P.; Rochowicz, K. Bibcode: 1996A&A...306..771R Altcode: The results of an extensive spectroscopic campaign on the eclipsing binary WR22 are presented. A new radial velocity curve is deduced for the WN7 component, allowing us to improve the parameters of the orbit, formerly determined on the basis of photographic spectra. The high signal-to-noise ratio of our data also allows the detection of some weak absorption lines which, for the first time, can definitely be attributed to the companion. A study of their radial velocities gives a mass ratio of m_WR_/m_O_=2.78 leading to a minimum mass of 72Msun_ for the WN7 star. The companion can be classified as a "late O" (O6.5-O8.5) star with a luminosity ratio of the system q=L_WR_^y^/L_O_^y^ at 5500A of about 8. The exceptionally high mass of the WN7 star and its high hydrogen mass-fraction suggest that WR22 is at the beginning of its Wolf-Rayet evolution. As a matter of fact, with such a high mass, WR22 most probably is still a hydrogen burning object. Therefore, the WN7 component is much closer to a main sequence O star with a "Wolf-Rayet clothing" than to the other members of the Wolf-Rayet family, which are rather highly evolved He-burning descendants of massive progenitors. Title: Chemical composition of solar-type stars Authors: Neuforge, C.; Magain, P. Bibcode: 1996ASPC..109..695N Altcode: 1996csss....9..695N No abstract at ADS Title: Empirical study of departures from the excitation equilibrium of FeI in metal-poor stars. Authors: Magain, P.; Zhao, G. Bibcode: 1996A&A...305..245M Altcode: A detailed analysis of neutral iron lines in a sample of 13 metal-poor dwarfs and subgiants is carried out on the basis of high resolution spectra obtained with the ESO Coude Echelle Spectrometer. The deduced iron abundance is found to depend on the excitation potential of the line used, higher excitation lines generally indicating higher abundances. This could be caused by departures from the local thermodynamic equilibrium (LTE) or by temperature inhomogeneities in the stellar atmospheres. The dependency of this effect on the stellar atmospheric parameters is investigated. From the comparison of iron lines with lines of other elements, it is concluded that the low excitation FeI lines are much more affected than the high excitation lines. The consequences of these effects for the classical abundance analyses are examined. It is found that they may explain, at least in part, some previously reported discrepancies between the results of different authors. Title: Photometric monitoring (1987 to 1994) of the gravitational lens candidate UM 425. Authors: Courbin, F.; Magain, P.; Remy, M.; Smette, A.; Claeskens, J. F.; Hainaut, O.; Hutsemekers, D.; Meylan, G.; van Drom, E. Bibcode: 1995A&A...303....1C Altcode: 1995astro.ph..4053C We present the results of a 7 year long photometric monitoring of two components (A and B) of UM 425, thought to be images, separated by 6.5", of the same z=1.47 quasar. These components have been imaged through an R filter in order to obtain their light curves. The photometry was obtained by simultaneously fitting a stellar two-dimensional profile on each component. The brightest image (component A, m_R_=15.7) shows a slow and smooth increase in brightness of 0.2 magnitude in seven years, while the faintest one (component B, m_R_=20.1) displays an outburst of 0.4 magnitude which lasts approximately two years. The variation of component B may be interpreted in two ways, assuming UM 425 is gravitationally lensed. If it is due to an intrinsic variation of the quasar, we derive a lower limit of 3 years on the time delay from the fact that it is not observed in component A. On the other hand, if it is a microlensing "High Amplification Event", we estimate the size of the source to be ~10^-3^pc, in agreement with standard models of AGNs. These observations are consistent with the gravitational lens interpretation of the object. Furthermore, all the CCD frames obtained under the best seeing conditions have been co-added, in an attempt to detect the deflector. The final R image reveals a rich field of faint galaxies in the magnitude range m_R_~22-24. No obvious deflector, nor any system of arcs or arclets is detected, down to a limiting magnitude of m_R_~24. Title: VizieR Online Data Catalog: Fe I in metal-poor stars (Magain+, 1996) Authors: Magain, P.; Zhao, G. Bibcode: 1995yCat..33050245M Altcode: A detailed analysis of neutral iron lines in a sample of 13 metal-poor dwarfs and subgiants is carried out on the basis of high resolution spectra obtained with the ESO Coude Echelle Spectrometer. The deduced iron abundance is found to depend on the excitation potential of the line used, higher excitation lines generally indicating higher abundances. This could be caused by departures from the local thermodynamic equilibrium (LTE) or by temperature inhomogeneities in the stellar atmospheres. The dependency of this effect on the stellar atmospheric parameters is investigated. From the comparison of iron lines with lines of other elements, it is concluded that the low excitation Fe I lines are much more affected than the high excitation lines. The consequences of these effects for the classical abundance analyses are examined. It is found that they may explain, at least in part, some previously reported discrepancies between the results of different authors. (1 data file). Title: Heavy elements in halo stars: the r/s-process controversy. Authors: Magain, P. Bibcode: 1995A&A...297..686M Altcode: It has been suggested by Truran (1981) that rapid neutron captures (the r-process) dominate the production of heavy elements in very metal-poor stars. Several spectroscopic works analyzing that hypothesis are reviewed and rediscussed and it is shown that there is, in fact, no secure observational evidence in support of Truran's suggestion. A method to determine the odd-to-even isotopic ratio of barium, and thus to estimate the relative contributions of the r and s-processes, is presented. It takes advantage of the hyperfine structure affecting the spectral lines of the odd isotopes to distinguish them from the even isotopes. This method, applied to the classical metal-poor subgiant HD 140283, shows that the barium isotopic ratio in that star is in agreement with a pure s-process production, and excludes any significant enhancement of the r-process contribution, in disagreement with previous works based on elemental abundances. Title: Stellar Atmospheres : The Link between Theory and Observation Authors: Magain, P. Bibcode: 1995LIACo..32..139M Altcode: 1995sews.book..139M No abstract at ADS Title: Barium Abundances of 20 Metal Deficient Stars Authors: Zhao, G.; Magain, P. Bibcode: 1995ASPC...81..574Z Altcode: 1995lahr.conf..574Z No abstract at ADS Title: A seven year campaign on WR 22 Authors: Rauw, G.; Vreux, J. -M.; Gosset, E.; Hutsemekers, D.; Magain, P.; Manfroid, J.; Remy, M.; Rochowicz, K. Bibcode: 1995IAUS..163..241R Altcode: No abstract at ADS Title: Vhrs - the Very High Resolution Spectrograph for the VLT Authors: Magain, P.; Dekker, H.; Delabre, B. Bibcode: 1995ESOSR..15....1M Altcode: No abstract at ADS Title: Elemental and Isotopic Abundances in Metal-Poor Stars Authors: Magain, P. Bibcode: 1995svlt.conf...79M Altcode: No abstract at ADS Title: WR22 as a core hydrogen-burning Wolf-Rayet star Authors: Rauw, G.; Vreux, J. M.; Gosset, E.; Hutsemekers, D.; Magain, P. Bibcode: 1995LIACo..32..463R Altcode: 1995sews.book..463R The analysis of an extensive sample of high resolution spectra of the Wolf-Rayet binary WR22 recently allowed us to determine a minimum mass of 72 M_solar for the WN7 star. With such a high mass, WR22 is expected to be a core H-Burning star which has just evolved from a progenitor of at least 90-110 M_solar. Title: VHRS: the Very High Resolution Spectrograph for the VLT. Authors: Magain, P.; Dekker, H.; Delabre, B. Bibcode: 1994fvlt.conf...37M Altcode: No abstract at ADS Title: (Erratum) Further observational evidence that MG J0414+0534 is a gravitational mirage. Authors: Angonin-Willaime, M. -C.; Vanderriest, C.; Hammer, F.; Magain, P. Bibcode: 1994A&A...292..722A Altcode: In Sect. 3.3, the identifications of components A1 and A2 for the optical data were inadvertently inverted. This does not change substantially the discussion; just read A1 for A2 and vice versa. In particular, the ratio A2/A1 = 0.3 cannot be made compatible with the radio value without one or several of the mechanisms we suggested. We apologize for the error and thank Dr S. Mao for bringing it to our attention. Erratum to Astron. Astrophys. 281, 388-394 (1994) Title: Further observational evidence that MG J0414+0534 is a gravitational mirage. Authors: Angonin-Willaime, M. -C.; Vanderriest, C.; Hammer, F.; Magain, P. Bibcode: 1994A&A...281..388A Altcode: Deep imaging of MG J0414+0534 with R and I filters reveals a faint, fuzzy and red object at the exact location expected for a lensing galaxy in the gravitational mirage hypothesis. Furthermore, the (extremely red and almost featureless) spectra of the 2 brightest components are very similar. These are strong indications that the system results from multiple gravitational imaging of a single source, but the nature of this source is not yet clear. It could be the nucleus of a low metallicity galaxy at a high redshift or a new type of object. Significant differences are observed between the flux ratios of the images at radio and optical wavelengths. The most likely explanation for this effect is a differential amplification of the image pair A_1_-A_2_ because of the large magnification gradient near a caustic. Title: On the linearity of ESO CCD#9 at CAT+CES. Authors: Gosset, E.; Magain, P. Bibcode: 1993Msngr..73...13G Altcode: No abstract at ADS Title: Gravitational Lensing Statistics Based on a Large Sample of Highly Luminous Quasars Authors: Surdej, J.; Claeskens, J. F.; Crampton, D.; Filippenko, A. V.; Hutsemekers, D.; Magain, P.; Pirenne, B.; Vanderriest, C.; Yee, H. K. C. Bibcode: 1993AJ....105.2064S Altcode: Results on gravitational lensing statistics applied to a sample of 469 highly luminous quasars are reported. The objects were directly imaged, either from the ground (ESO, CFH) under optimal seeing conditions, or using the Hubble Space Telescope. We have derived values for the effectiveness parameter F of galaxies, modeled by means of singular isothermal spheres, to produce macrolensed images of distant quasars, and upper limits on the density parameter {OMEGA}_L_ of compact objects with masses ~10^10^ - 10^12^ M_sun_. Adopting H_0_ = 50 km/s/Mpc, {OMEGA}_0_= 1 and λ = 0, we find that at the 99.7% confidence level, 0.005 < F < 0.478 and that {OMEGA}_L_ < 0.02. A critical discussion of these results is presented. Finally, comparing the efficiencies of ground-based and space instruments used to search for gravitational lens systems among highly luminous quasars, we conclude that for the near future, ground based direct imaging characterized by a good dynamical range still constitutes the best observational strategy. Title: Erratum - Q:1208+1011 - the Most Distant Multiply Imaged Quasar or a Binary Authors: Magain, P.; Surdej, J.; Vanderriest, C.; Pirenne, B.; Hutsemekers, D. Bibcode: 1993A&A...272..383M Altcode: In the title of this Letter, the word "multiply" was accidentally omitted. The correct title is shown above. Title: Barium isotopes in the very metal-poor star HD 140283. Authors: Magain, P.; Zhao, G. Bibcode: 1993A&A...268L..27M Altcode: The fractions of odd and even isotopes of barium in the metal-poor star HD140283 are determined from an analysis of the profile of the Ba II resonance line, taking advantage of the differences in hyperfine structure splitting between the different isotopes. Although one would expect an increased contribution of the r-process in very metal-poor stars, it is found that the isotopic ratio is very close to solar. Title: Search for gravitational lenses in a large sample of highly luminous quasars and statistical determination of cosmological parameters Authors: Claeskens, J. F.; Crampton, D.; Filippenko, A. V.; Hutsemekers, D.; Magain, P.; Pirenne, B.; Surdej, J.; Vanderriest, C.; Yee, H. K. C. Bibcode: 1993LIACo..31..263C Altcode: 1993glu..conf..263C Results on gravitational lensing statistics applied to a sample of 469 highly luminous quasars are reported. Title: Barium isotopes in metal-poor stars. Authors: Magain, P.; Zhao, G. Bibcode: 1993oee..conf..480M Altcode: No abstract at ADS Title: Coincidences Authors: Magain, P.; Remy, M. Bibcode: 1993LIACo..31..137M Altcode: 1993glu..conf..137M No abstract at ADS Title: Two new very close pairs of quasars with discordant redshifts and a gravitational lens candidate. Authors: Surdej, J.; Remy, M.; Smette, A.; Claeskens, J. -F.; Magain, P.; Refsdal, S.; Swings, J. -P.; Veron-Cetty, M. Bibcode: 1993Lie93..31..153S Altcode: No abstract at ADS Title: The cloverleaf quasar H1413+117: a preliminary light curve Authors: Arnould, P.; Remy, M.; Gosset, E.; Hainaut, O.; Hutsemekers, D.; Magain, P.; Smette, A.; Surdej, J.; van Drom, E. Bibcode: 1993LIACo..31..169A Altcode: 1993glu..conf..169A The cloverleaf quasar H1413+117 was discovered to be a gravitational lens system in 1988. Since then, it has been photometrically monitored essentially as part of the ESO key-program Gravitational lensing: we present here a first preliminary lightcurve for its four individual images. Title: Galaxies statistics around highly luminous quasars: the ESO Sample Authors: van Drom, E.; Surdej, J.; Magain, P.; Hutsemekers, D.; Gosset, E.; Claeskens, J. F.; Shaver, P.; Melnick, J. Bibcode: 1993LIACo..31..301V Altcode: 1993glu..conf..301V We present observational evidence on the correlation between the positions of Highly Luminous Quasars and those of galaxies for a sample of 136 objects, observed under good seeing conditions. Title: The relative photometric lightcurve of UM673 A&B Authors: Daulie, G.; Hainaut, O.; Hutsemekers, D.; Magain, P.; Remy, M.; Smette, A.; Surdej, J.; van Drom, E. Bibcode: 1993LIACo..31..181D Altcode: 1993glu..conf..181D From 1987 to 1993, we have carried out at ESO a photometric monitoring of the gravitationally lensed quasar UM673. The main result is that the two lensed images of UM673 did not show any significant relative variation during more than five years. Title: ESO key programme, gravitational lensing: quasars and radio galaxies; a status report Authors: Surdej, J.; Angonin, M. C.; Arnaud, J.; Bauer, T.; Borgeest, U.; Hainaut, O.; Hammer, F.; Hutsemekers, D.; Le Fevre, O.; Nottale, L.; Magain, P.; Meylan, G.; Remy, M.; Shaver, P.; Smette, A.; Swings, J. P.; van Drom, E.; Veron-Cetty, M.; Veron, P. Bibcode: 1992daec.conf...97S Altcode: The scientific background and objectives of our ESO Key Programme are first recalled. A brief account of our research activities (observing runs at ESO and elsewhere, meetings, etc.) is then given. Preliminary scientific results are presented concerning 1) our observational database for highly luminous quasars and distant powerful radiogalaxies; 2) speckle observations of highly luminous quasars; 3) the photometric monitoring and 4) detailed studies of several known gravitational lenses; 5) optical observations of 3C and 4C radio galaxies and 6) of the well known Einstein ring MG 1131+0456. Title: A Spectroscopic Study of UM 673 A and B: On the Size of Lyman-Alpha Clouds Authors: Smette, A.; Surdej, J.; Shaver, P. A.; Foltz, C. B.; Chaffee, F. H.; Weymann, R. J.; Williams, R. E.; Magain, P. Bibcode: 1992ApJ...389...39S Altcode: We present a study of the Lyα forest spectra (2 A resolution) obtained for the A and B images of the gravitationally lensed high- redshift quasar UM 673. We also present higher resolution data of the brightest (A) image. In the 2 A resolution spectra, all the absorption lines detected at 5 σ in the spectrum of the fainter B image are present in the A image; however, we find two anticoincidences, i.e., two lines in A which do not have a counterpart in B at more than a 3 σ confidence level. Given the fact that corresponding Lyα lines in the spectra of A and B have their equivalent widths well correlated, this proves that both light beams actually cross the same clouds. Most of the velocity differences between corresponding lines are compatible with 0 km s^-1^ within the error bars, with a standard deviation of 17 km s^-1^. As the comoving linear separation increases from virtually 0h^-1^_50_ kpc (H_0_ = 50h_50_ km s^-1^ Mpc^-1^, q_0_ = 0) at the redshift of the QSO to 2h^-1^_50_ kpc, we derive a best value of 12h^-1^_50_1 kpc for the 2 σ lower limit and of 160h^-1^_50_ kpc for the 2 σ upper limit of the diameter of spherical Lyα clouds in the redshift range 2.1-2.7, by means of Monte Carlo simulations. However, if we interpret the two anticoincidences as due to a Mg II doublet at z = 0.4261, we find in this case a best value of 23h^-1^_50_ kpc to the 2 σ lower limit of the Lyα cloud diameter, but we cannot derive any upper limit. For the two major heavy-element systems detected in the spectrum of UM 673, we do not find any significant difference between the corresponding lines in the two spectra, indicating that these systems do not show dramatic variations over scales of 0.8h^-1^_50_ and 2.1h^-1^_50_ kpc, respectively. Title: The new gravitational lens candidate Q 1208+1011 and the importance of high quality data. Authors: Magain, P.; Surdej, J.; Vanderriest, C.; Pirenne, B.; Hutsemékers, D. Bibcode: 1992Msngr..67...30M Altcode: 1992Mgr....67...30M No abstract at ADS Title: Using the HST Archive - gravitational lenses from the Snapshop Survey Authors: Pirenne, B.; Surdej, J.; Magain, P. Bibcode: 1992STECF..17...22P Altcode: No abstract at ADS Title: Search for gravitational lensing in a sample of highly luminous quasars Authors: Magain, P.; Hutsemekers, D.; Surdej, J.; Vandrom, E. Bibcode: 1992LNP...406...88M Altcode: 1992grle.conf...88M The status of the ESO survey for gravitational lensing among highly luminous quasars (HLQs) is briefly reviewed. The statistics of lensing, both concerning the multiple images and the associations of galaxies with quasars, are examined. We find a significant overdensity of galaxies very close to the line-of-sight to the HLQs. We also report the discovery of a new multiply lensed quasar candidate. Title: Magain P., Surdej J., Vanderriest C., Pirenne B., Hutsemekers Authors: Magain, P.; Surdej, J.; Vanderriest, C.; Pirenne, B.; Hutsemekers, D. Bibcode: 1992A&A...253L..13M Altcode: We report the discovery of a new gravitational lens candidate: the high redshift (z = 3.803) and highly luminous (V = 17.5, M_V_ = - 30.3) quasar Q 1208+1011. As derived from the analysis of direct CCD frames taken with the ESO/MPI 2.2m telescope, this multiple quasar consists of two point-like images, separated by 0.45" and characterized by a brightness ratio of 3.5, in red light. Existing spectroscopic data support the gravitational lens interpretation for this system but cannot exclude the hypothesis of a binary quasar. In the former case, the spectrum suggests that, if the metallic absorption line system reported by Steidel (1990) at a redshift z = 2.9157 is associated with the deflector, the mass of the lens should be of the order of M = 7.8 10^11^M_sun_(q_0_ = 0, H_0_ = 50 km s^-1^ Mpc^-1^). Evaluation of a recent HST PC frame obtained for Q 1208+1011 within the snapshot survey for gravitational lenses confirms the above results. Title: Gravitational lensing statistics based on a large sample of highly luminous quasars observed with ground-based telescopes and HST Authors: Surdej, J.; Claeskens, J. F.; Crampton, D.; Filippenko, A. V.; Hutsemekers, D.; Magain, P.; Pirenne, B.; Vanderriest, C.; Yee, H. K. C. Bibcode: 1992ESOC...44..111S Altcode: 1992swhs.conf..111S We present here some recent results on gravitational lensing statistics as applied to a sample of 470 highly luminous quasars. Title: Optical observations of gravitational lenses Authors: Surdej, J.; Claeskens, J. F.; Hutsemekers, D.; Magain, P.; Pirenne, B. Bibcode: 1992LNP...406...27S Altcode: 1992grle.conf...27S We report here on some of the major developments achieved on optical observations of gravitational lenses since the last conference devoted to 'Gravitational Lensing'. Title: Calibration of the alpha Centauri system : metallicity and age. Authors: Noels, A.; Grevesse, N.; Magain, P.; Neuforge, C.; Baglin, A.; Lebreton, Y. Bibcode: 1991A&A...247...91N Altcode: The binary system Alpha Cen A and B, with its well known parallax, its high quality orbit and the reasonable hypothesis of a common origin and age for both components, is a useful test of stellar evolution models. Evolutionary sequences are computed for 1.085 and 0.9 solar masses with different values of Z, Y and alpha (= l/Hp). Adopting luminosities and effective temperatures as derived from the observations, Z = 0.04, Y = 0.32, alpha = 1.6 and t = 5 Gyr. The Z-value derived from evolutionary sequences is very sensitive to the difference in effective temperature between the two components. Title: Abundances of neutron capture elements in metal-poor dwarfs. I Yttrium and zirconium. Authors: Zhao, G.; Magain, P. Bibcode: 1991A&A...244..425Z Altcode: The yttrium and zirconium abundances are determined in a sample of 20 metal-poor stars on the basis of high resolution, high SNR spectra. Significant differences between the behaviors of these two neighboring elements are found, zirconium being less deficient than yttrium in Population II stars. Moreover, there is a genuine cosmic scatter in the abundances of these two elements relative to iron, of the order of 20 percent. The scatter is lower when these elements are compared to titanium, which might indicate that a significant fraction of the lighter neutron-capture elements are produced in massive stars. Title: A Spectroscopic Study of UM673 A &B: on the size of Lyman- αClouds Authors: Smette, A.; Surdej, J.; Shaver, P. A.; Foltz, C. B.; Chaffee, F. H.; Weymann, R. J.; Williams, R. E.; Magain, P. Bibcode: 1991qal..work...37S Altcode: No abstract at ADS Title: Miscellaneous spectroscopic observations of quasars and quasar candidates. Authors: Veron, P.; Veron-Cetty, M. -P.; Djorgovski, S.; Magain, P.; Meylan, G.; Surdej, J. Bibcode: 1990A&AS...86..543V Altcode: We report about new spectroscopic observations of 11 quasar candidates, 19 quasars with uncertain redshift and three BL Lac candidates, and 11 objects located within few arcseconds from a quasar. Title: The chemical composition ofthe extreme halo stars. III. Equivalent widths of 20. Authors: Zhao, G.; Magain, P. Bibcode: 1990A&AS...86...85Z Altcode: In the first two papers of this series the chemical composition of 20 extreme halo stars was discussed. The abundances of a number of elements were determined using model atmosphere analysis of equivalent widths. In this paper a tabulation of the equivalent width data is presented. A comparison of the measurements with the equivalent widths from different sources is used to assess the quality of the data. Title: New Observations and Gravitational Lens Models of the Cloverleaf Quasar H1413+117 Authors: Kayser, R.; Surdej, J.; Condon, J. J.; Kellermann, K. I.; Magain, P.; Remy, M.; Smette, A. Bibcode: 1990ApJ...364...15K Altcode: New optical and radio observations of the quadruple quasar H1413 + 117, the Cloverleaf, carried out with the 1.54 m Danish telescope at ESO and with the VLA at NRAO are presented. The VLA data, obtained in the A configuration at 3.6 cm, show radio counterparts at the positions of the four optical images and an additional strong radio source between images B and D. Gravitational lens models of H1413 + 117 using (a) a single elliptical galaxy and (b) two spherical galaxies are presented, which fit the positions of the four images of the quasar remarkably well. The models suggest that the strong radio source is a feature of the quasar, e.g., an ejected blob, which lies right on the caustic of the lens and is thereby strongly amplified. The time delays predicted by our models are sufficiently short to allow for their determination within one observational season, making H1413 + 117 an exceptionally well suited object for gravitational lens research. Title: Core velocity dispersion and mass-to-light ratio of the old Magellanicglobular cluster NGC 1835. Authors: Dubath, P.; Meylan, G.; Mayor, M.; Magain, P. Bibcode: 1990A&A...239..142D Altcode: The projected velocity dispersion in the core of the old Large Magellanic Cloud globular cluster NGC 1835 is deduced from integrated light spectra obtained at the European Southern Observatory (ESO) with CASPEC, the Cassegrain ESO Echelle Spectrograph mounted on the ESO 3.6-m telescope at La Silla, Chile. A numerical cross-correlation technique gives a projected velocity dispersion σ_p_(core) = 10.1 + 0.2 km s^-1^. Multimass anisotropic King-Michie dynamical models are applied to the observational constraints given by the surface brightness profile and the above central projected velocity dispersion. Depending on the model, the values obtained for the total mass of the cluster range from 0.70 to 1.55 10^6^ M_sun_, with a mean total mass <M_tot_> = 1.0 +/- 0.3 10^6^ M_sun_, corresponding to a global mass-to-light ratio <M/L_V_> = 3.4 +/- 1.0 (M/L_V_). The present study shows that when the same kind of dynamical models (King-Michie) constrained by the same kind of observations (surface brightness profile and central value of the projected velocity dispersion) are applied to an old rich Magellanic globular cluster, viz., NGC 1835, the results seem similar to those obtained in the case of galactic globular clusters. Consequently, the rich old globular clusters in the Magellanic clouds could be quite similar (in mass and M/L_V_) to the rich globular clusters in the Galaxy. Title: The chemical composition of the extreme halo stars. II. Green spectra of 20 dwarfs. Authors: Zhao, G.; Magain, P. Bibcode: 1990A&A...238..242Z Altcode: The abundances of nine elements in the atmospheres of 20 extreme metal-poor stars are derived from green spectra obtained with the ESO Cassegrain Echelle Spectrograph (CASPEC). Sodium is found to be overabundant with respect to aluminum by as much as one dex. There is some scatter in Ca/Fe which cannot be accounted for by random errors in equivalent widths or atmospheric parameters. Scandium is overabundant relative to iron. Some barium lines may be affected by strong departures from local thermodynamic equilibrium. The nitrogen-rich metal-poor star HD 74000, which was found in previous work to be also Al-rich, also presents higher than usual abundances of Na and of s-process elements. It can thus be considered as a mild barium dwarf of Population II. Title: High-Resolution Spectroscopy of the C 2 Swan 0--0 Band from Comet P/Halley Authors: Lambert, D. L.; Sheffer, Y.; Danks, A. C.; Arpigny, C.; Magain, P. Bibcode: 1990ApJ...353..640L Altcode: High-resolution spectra of the C2 Swan system's 0-0 band from Comet P/Halley in March 1986 show that the populations of the upper state's rotational levels may be described by two rotational temperatures. The low rotational levels provide a low temperature, Trot = about 600 - 700 K. The higher levels correspond to about 3200 K. If a contribution from the 3200-K molecules is subtracted from the populations of the low-J-prime levels, the latter are characterized by Trot = about 190 K. A comparison with recent predictions for C2 molecules fluorescing in sunlight shows that the observed and predicted level populations are in good agreement for J-prime greater than about 15, but there is a sharp disagreement for the low rotational levels. Title: A search for gravitational lensing among highly luminous quasars : observational strategy and survey Authors: Swings, J. P.; Magain, P.; Remy, M.; Surdej, J.; Smette, A.; Hutsemekers, D.; van Drom, E. Bibcode: 1990LNP...360...83S Altcode: 1990grle.work...83S The observational technique used for our search for gravitational mirages is presented : recent results, as well as future observations, are outlined. Title: Preliminary analysis of high-resolution spectra for UM 673 A & B Authors: Smette, A.; Surdej, J.; Shaver, P. A.; Foltz, C. B.; Chaffee, F. H., Jr.; Magain, P. Bibcode: 1990LNP...360..122S Altcode: 1990grle.work..122S No abstract at ADS Title: A Search for Gravitational Lensing Among Highly Luminous Quasars: New Results Authors: Magain, P.; Remy, M.; Surdej, J.; Swings, J. -P.; Smette, A. Bibcode: 1990LNP...360...88M Altcode: 1990grle.work...88M Images of highly luminous QSOs are analyzed to determine whether the gravitational magnification of the background QSO by matter associated with the foreground galaxies accounts for the excess of galaxies in the fields of distant QSOs. Galaxy detection is increased by utilizing red-filter images, 40 taken with the EFOSC at the ESO 3.6-m telescope and 43 taken with a direct CCD camera at the ESO/MPI 2.2-m telescope. The R-magnitude ranges from 22.5 to 23.0 for the sample, for which the number of galaxies is counted by eye, showing 45 galaxies of radio and optical type. The overdensity found is not as pronounced as that of Fugmann (1988) or that of Webster et al. (1988). A systematic subtraction of the point spread function is also described to investigate the idea that some galaxies responsible for the QSO light magnification are within the inner 3-arcsec circle. The galaxies very close to the line-of-sight are theorized to contribute significantly to the magnification of these QSOs. Title: Two more very massive stars resolved. Authors: Heydari-Malayeri, M.; Magain, P.; Remy, M. Bibcode: 1989A&A...222...41H Altcode: We present new evidence against the existence of very massive stars in the Magellanic Clouds. Using high resolution CCD images and appropriate image restoration methods, we show that Sk 157 and Sk-69^deg^253 (Sanduleak, 1968, 1969), lying in the SMC and LMC respectively, are not single, very massive, but multiple systems. Thus, two of the most massive stars in existence, with the estimated masses of ~ 85 _sun_ and > 120 M_sun_, vanish from astronomy. The results presented here have important implications for star formation models and the extragalactic distance scale. Title: A study of the interstellar medium in line to NGC 5128 from high resolution observations of the supernova 1986G. Authors: D'Odorico, S.; di Serego Alighieri, S.; Pettini, M.; Magain, P.; Nissen, P. E.; Panagia, N. Bibcode: 1989A&A...215...21D Altcode: 1989A&A...215...21O We present new high resolution, high S/N ratio spectra of supernova 1986G in NGC 5128 (Cen A). These data allow a detailed study of the rich interstellar absorption spectrum originating in the line of sight to the SN. At least 12 distinct Ca II and Na I absorbing clouds are identified. The gas associated with NGC 5128 is spread over a velocity range of 178 km s^-1^ and it is split in at least 7 components. A new result unique to NGC 5128 is the presence of 3 components with Ca^+^/Na^0^ column densities ratios smaller than 1, that is typical of cool disc gas. This is interpreted as a further indication of the existence of an extended warped disc or a ring of cool gas. From the discussion of the velocities of the absorption components seen in its spectrum it is inferred that the SN was at least half way within the dust and gaseous disc of the galaxy. An intriguing result of this work is the discovery of two absorption components at v_H_ = 236 and 257 km s^-1^, which cannot be easily explained within the velocity field of either the Galaxy or NGC 5128, and may be related to high velocity clouds of neutral hydrogen observed at nearby lines of sight. We detected and measured several diffuse interstellar bands at galactic and NGC 5128 velocities. This is the first time that such a detailed study has been done in a galaxy beyond the Magellanic Cloud. At NGC 5128 velocities, we also detected, for the first time beyond the Local Group, molecular absorption lines of CH and CH^+^ at optical wavelengths. Title: What is the mass-to-light ratio of the old Magellanic globular cluster NGC 1835? Authors: Meylan, G.; Dubath, P.; Mayor, M.; Magain, P. Bibcode: 1989Msngr..55...55M Altcode: 1989Mgr....55...55M We astronomers are lucky: our Galaxy as two companion galaxies, the Large and Small Magellanic Clouds, situated weil above the galactic plane, which Contain a huge potential of astrophysical information. For example, concern: ng star clusters, the realm of the globuar clusters is much richer and more Varied in the Magellanic Clouds than in the Galaxy: rich clusters of all ages are observed, from the youngest, having ages of a few tens 10^6 yr to the oldest 1haV'lng ages of the order"or larger than 10 10^9 yr. In this paper, only old Magellanic and galactic globular clusters are considered. Title: Absolute dimensions of eclipsing binaries. XIV. UX Mensae. Authors: Andersen, J.; Clausen, J. V.; Magain, P. Bibcode: 1989A&A...211..346A Altcode: Spectroscopic orbits are determined for the 4-day, F8 V eclipsing binary UX Mensae. The masses of the binary components are 1.24 and 1.20 solar masses with errors of + or - 0.5 percent. The results of the analysis of the uvby light curves by Clausen and Gronbech (1976) are confirmed. The metal abundance is found to be Fe/H = +0.04 + or - 0.10. Absolute dimensions are computed for the binary. Theoretical evolutionary sequences for the masses and metal abundance are interpolated from the models of VandenBerg (1988) and Andersen et al. (1988). Title: IRC +10216: a peanut nebula! Authors: Le Bertre, T.; Magain, P.; Remy, M. Bibcode: 1989Msngr..55...25L Altcode: Carbon stars with low effective temperature (2,000-3,000 K) are thought to be long-period variables evolving on the Asymptotic Giant Branch (AGB). These objects are burning alternately hydrogen and helium in different shells around a degenerate core of carbon and oxygen [1]. Material processed during the helium burning phase is dredged-up by convection to the surface and enriches it in carbon relative to oxygen. Title: Profiles of a Key Programme: Gravitational Lensing Authors: Surdej, J.; Arnaud, J.; Borgeest, U.; Djorgovski, S.; Fleischmann, F.; Hammer, F.; Hutsemekers, D.; Kayser, R.; Le Fevre, O.; Nottale, L.; Magain, P.; Meylan, G.; Refsdal, S.; Remy, M.; Shaver, P.; Smette, A.; Swings, J. P.; Vanderriest, C.; van Drom, E.; Véron-Cetty, M.; Véron, P.; Weigelt, G. Bibcode: 1989Msngr..55....8S Altcode: 1989Mgr....55....8S Prior to Professor van der Laan's enquiry, in the March 1988 issue of the Messenger, on the general interest among astronomers from the European community to possibly participate in Key Programmes (KPs) at the European 80uthern Observatory, at least three distinct groups (including more than half of the above authors) were already involved in the study of "gravitational lensing" effects (see box on pages 10-11). Observations were being performed with the help of various telescopes on La 8illa as weil as at other observatories (VLA, CFHT, Palomar, Kitt Peak, etc.). Title: Core Velocity Dispersion of the LMC Globular Cluster NGC 1835 Authors: Meylan, G.; Dubath, P.; Mayor, M.; Magain, P. Bibcode: 1989BAAS...21..711M Altcode: No abstract at ADS Title: A Simple Deconvolution Algorithm Authors: Magain, P. Bibcode: 1989ESOC...31..205M Altcode: 1989daan.work..205M A very simple image deconvolution algorithm is described in three cases. It is first established in the case of noise-free data. Then, a method for taking noise into account is presented. Finally, a smoothing constraint is included in the algorithm. Title: The chemical composition of the extreme halo stars. I. Blue spectra of 20 dwarfs Authors: Magain, P. Bibcode: 1989A&A...209..211M Altcode: Spectra obtained with the ESO Cassegrain echelle spectrograph are used to determine the abundances of 13 elements in the atmospheres of 20 extreme halo dwarfs. It is found that the alpha elements Mg, Ca, and Ti are overabundant with respect to Fe, that the Cr/Fe ratio is solar at all metallicities, and that Al is overdeficient relative to Mg. The results also indicate that the s elements Sr, Y, and Ba are overdeficient with respect to Fe in stars with Fe/H ratios of less than 2.3, and that for ratios greater than 2.3 the s element abundances relative to Fe are roughly constant (at either solar or higher values). Title: New evidence against the existence of very massive stars. Authors: Heydari-Malayeri, M.; Magain, P.; Remy, M. Bibcode: 1988A&A...201L..41H Altcode: The most luminous stars are our first probes for exploring the stellar content of distant galaxies. They have also been used as standard candles for extragalactic distance determinations. We show that Sk-66^deg^ 41, one of the brightest stars in the Large Magellanic Cloud (LMC), is a multiple system consisting of at least six components. This result has important consequences for the understanding of star formation mechanisms, especially the upper limit to stellar masses. Moreover, when primary distance indicators are not available, care should be taken in using the brightest blue stars. The derived distances, depending on the number of cluster members, can easily be underestimated by more than a factor 2, leading to larger values for the Hubble constant. Title: Discovery of a quadruply lensed quasar: the 'clover leaf H1413 + 117 Authors: Magain, P.; Surdej, J.; Swings, J. -P.; Borgeest, U.; Kayser, R. Bibcode: 1988Natur.334..325M Altcode: 1988Nat...334..325M In November 1986 we began an optical search for examples of gravitational lensing in a sample of highly luminous quasars (HLQs, Mv < -29), with the aims of improving our knowledge of the quasar luminosity function, studying the dark matter content of the Universe, and redetermining some important cosmological parameters. This survey has found one new case of lensing1,2 and the general implications of the search have been summarized3. Here we report the discovery of a second gravitational lens system in the broad absorption line quasar H1413 + 117 (refs 4-6). Four images of comparable brightness are seen, separated by ~1 arcsec. Spectra obtained of two of the images are identical apart from the presence of sharp absorption lines in one component, which are presumably due to gas clouds along the line of sight. The unique configuration of the images, together with the fairly rare occurrence of this type of quasar, makes it incontrovertible that this is a lensed system, not a cluster of quasars, and this second discovery made by imaging bright quasars establishes the power of the method for finding systems with small separations. Title: Observations of the new gravitational lens system UM 673 = Q 0142-100. Authors: Surdej, J.; Magain, P.; Swings, J. -P.; Borgeest, U.; Courvoisier, T. J. -L.; Kayer, R.; Kellermann, K. I.; Kuhr, H.; Refsdal, S. Bibcode: 1988A&A...198...49S Altcode: In order to better understand the effects of gravitational lensing on the observed quasar luminosity function, on the source counts of extragalactic objects, etc., we have recently initiated a high resolution direct imaging survey of a selected sample of Highly Luminous Quasars (HLQs). The observations are being carried out with the 2.2 m telescope at ESO, and with the VLA at the NRAO, New Mexico. Following a first observing run at ESO, we have reported the discovery of a new gravitational lens system for the HLQ UM 673 = Q0142-100. Additional observations supporting this interpretation are discussed here. We confirm that UM 673 is resolved into two quasi-stellar images A(m_V_=17.0) and B(m_V_=19.1) separated by 2.22" and having essentially the same redshift (z_e_=2.719 with z_e_(A)- z_e_(B)=-0.0002 +/-0.0008). Their emission (Lyα, N V, Si IV, C IV, etc.) as well as absorption (including a high ionization system at z_a_=2.3564) line spectra also appear to be quite identical. Further evidence for the presence of a lensing galaxy (m_R_=19, z_g_=0.49) between the two QSO images is given by the detection of faint absorption lines due to Ca II H and K, and possibly Na I D1 and D2, at a redshift z=0.493 in the spectrum of UM 673 B. Application of gravitational optometry to this system is given in the present article: a value of M_0_ = 2.4 10^11^ M_sun_ is derived for the mass of the lensing galaxy located between UM 673 A and B and a most likely estimate of {DELTA}t = 7 weeks is found for the expected delay between the arrival times of a similar variability event in the two lensed images of the quasar (H_0_=75 km s^-1^ Mpc^-1^, q_0_=0). A VLA observation of UM 673 has been obtained at 6 cm in the hybrid C/D-array configuration. This radio map indicates the presence of a faint elongated structure which is possibly associated with the UM 673 gravitational lens system. Title: The SMC compact blob N 81 : a detailed multi-wavelength investigation. Authors: Heydari-Malayeri, M.; Le Bertre, T.; Magain, P. Bibcode: 1988A&A...195..230H Altcode: This paper is devoted to an extensive investigation of the compact Small Magellanic Cloud H II region N81. Several observational techniques with various telescopes at ESO have been employed to acquire a multi-aspect view of the physical characteristics of this interesting nebula: CCD, IDS and Reticon high, medium and low resolution spectroscopy (range 3700-10000 A), CCD imaging using 17 different filters, optical and infrared photometry at UBVRI and JHK. We also use the H I emission observations reported in the literature. The nebula N81 is probably excited by one star of about 60 M_sun_, (T_eff_ = 47500 K) accompanied by a cluster of about 10 B0 stars (M = 15 M_sun_, T_eff_ = 32000 K). We derive the absolute visual magnitude of the exciting star to be -5.1, corresponding to a bolometric magnitude of M_bol_= -9.1 and a luminosity of 3.5 10^5^ L_sun_. This nebula is a young H II region. From the equivalent width of the Hβ emission line we derive an age of 2.5 10^6^yr for N81. We stress the importance of correcting the continuum emission around Hβ for the nebular contribution. We derive the gas electron density and temperature and compute the chemical abundances of He, O, N, Ne, S, and Ar. The results are compared with the mean values available for the SMC. The high resolution profile of N81 at Hβ was decomposed into its various components. We find the most probable three dimensional turbulent velocity in N81 to be about 3 km s^-1^. We observationally confirm the proposition by Koornneef and Israel (1985) that the H_2_ emission may be produced by the action of a mild shock moving through the ambient cloud of this nebula. Interestingly, unlike other representatives of this category of H II regions in the Magellanic Clouds, N81 is not affected by the local dust. The nebula N81 is associated with the SMC H I cloud of radial velocity +167 km s^-1^, observed by McGee and Newton (1981). The neighboring H II complexes N83 are associated with a density peak of this H I cloud. N 88 A, another SMC H II blob, lying in the vicinity of N 81, is associated with another H I cloud. We speculate that N 81 and N 88 A may have been formed due to a collision between these two clouds. Title: Very low upper limits on the strength of interstellar lithium lines toward SN 1987A. Authors: Baade, D.; Magain, P. Bibcode: 1988A&A...194..237B Altcode: Seven CCD and eleven Reticon spectra of high spectral resolution and low noise have been carefully analysed in search for faint absorption lines due to neutral interstellar lithium λ 6708 A along the line of sight to SN 1987A in the Large Magellanic Cloud (LMC). At the velocities of the strongest interstellar Ca II and Na I lines, no evidence of any interstellar feature has been found. An upper limit for the strongest components expected is 0.15 mA for both the Galaxy and the LMC. From these we infer elemental column densities N_Galaxy_ <= 2.6 10^11^ cm^-2^ and N_LMC_ <= 1.4 10^11^ cm^-2^ and gaseous elemental abundances (Li/H I)_Galaxy_ <= 7.7 10^-10^ and (Li/H I)_LMC_ <= 1.0 10^-10^ with an estimated uncertainty of the abundance limits of a factor of 4 (0.6 dex). Title: Pre- and post-perihelion spectrographic and photometric observations of Comet Wilson (1986 l) Authors: Arpigny, C.; Dossin, F.; Manfroid, J.; Magain, P.; Haefner, R. Bibcode: 1988Msngr..51...27A Altcode: The behavior of Comet Wilson before and after its passage through perihelion, which occurred on April 21, 1987, was studied on the basis of spectrographic and photometric observations. Results pertaining to spectra in the UV, blue, and red regions, and to photometry through narrow-band filters are presented. It is suggested that the fading of Comet Wilson might reflect some general trend in the comet's evolution, or that it could be the result of a geometrical effect associated with the rotation of the comet's nucleus and the presence of discrete active areas on its surface. Title: Search for Gravitational Lensing from a Survey of Highly Luminous Quasars Authors: Surdej, J.; Swings, J. -P.; Magain, P.; Borgeest, U.; Kayser, R.; Refsdal, S.; Courvoisier, T. J. -L.; Kellermann, K. I.; Kuhr, H. Bibcode: 1988ASPC....2..183S Altcode: 1988osq..conf..183S The authors have shown that their search for gravitational lensing from a survey of optically selected highly luminous quasars (HLQ) appears very promising. Observational features (multiple images, image elongation, jet-like feature, fuzz, etc.) possibly associated with the HLQ phenomenon have been detected for more than 20% of the objects under study. While it is not yet known how many of the HLQs are gravitational mirages, at least 5 (out of 111) of the investigated quasars appear to be highly luminous because of amplification of their brightness by gravitational lensing. Title: Could the gravitational lensing alter the observational data in the extragalactic field? Authors: Surdej, J.; Magain, P.; Swings, J. P.; Remy, M.; Borgeest, U.; Kayser, R.; Refsdal, S.; Kühr, H. Bibcode: 1988lsso.conf...95S Altcode: No abstract at ADS Title: Non-Lte Effects and Abundance Analyses of Halo Stars Authors: Magain, P. Bibcode: 1988IAUS..132..485M Altcode: The possible existence of departures from LTE affecting the abundance analyses of halo dwarfs and subgiants is analysed from the observational point of view, and illustrated by the case of the intermediate halo subgiant HD 76932. Title: A new CCD camera for the Echelec spectrograph. Authors: Gilliotte, A.; Magain, P. Bibcode: 1987Msngr..50...46G Altcode: The Echelec spectrograph, installed at La Silla in 1973, was designed to be used with an electronographic camera. However, by adding a flatfield corrector, it can be operated with other detectors, such as CCD's. As part of the upgrading programme of the 1.52-m telescope, and in order to improve the spectroscopic capabilities of that instrument, the Echelec spectrograph has been modified and is now working with the same CCD detector as used on the Boiler and Chivens spectrograph. Title: Resolution of the OI + NH2 Blend in Comet p/ Halley Authors: Arpigny, C.; Magain, P.; Manfroid, J.; Dossin, F.; Danks, A. C.; Lambert, K. L. Bibcode: 1987A&A...187..485A Altcode: Spectra of comet P/Halley have been taken at very high resolution (0.015 nm) with a view to evaluating the contamination of the forbidden oxygen doublet at 630 nm by NH2 features at low resolution. Comparison is made with a few other bright comets. Appreciable variations are found not only in the NH2/[O I] ratio but also in the relative intensities of the various NH2 emissions themselves. The authors comment upon the accuracy obtained on the oxygen abundance derived from the [O I] lines. Mapping of these emissions over the coma is required in order to correctly remove any important NH2 contribution at low resolution. This should in addition provide information bearing upon the origin of the oxygen atoms in the 1D level. Title: A new case of gravitational lensing Authors: Surdej, J.; Magain, P.; Swings, J. -P.; Borgeest, U.; Courvoisier, T. J. -L.; Kayser, R.; Kellermann, K. I.; Kuhr, H.; Refsdal, S. Bibcode: 1987Natur.329..695S Altcode: 1987Nat...329..695S Even before the discovery of the first gravitational lens system1 in 1979 (see ref. 2 for a recent review of the other published candidates), it was recognized that a statistical evaluation of the occurrence of gravitational lensing within a well-defined sample of quasars is important to understand better the quasar luminosity function and possibly the QSO phenomenon itself3, to test cosmological models4,5 and to probe the luminous and dark matter distribution on various scales in the Universe4-6. A year ago, we began a systematic search from the European Southern Observatory (ESO) at La Silla, Chile, for gravitational lens systems in a selected sample of highly luminous quasars; Mv<-29.0. These objects are promising candidates for gravitationally lensed QSO images with arc-second and sub-arc-second separations (J.S. et al., manuscript in preparation and refs 7 and 8). Since December 1986, we have identified four possible cases. Here we give a brief description of our first identified gravitational lens system UM673 = Q0142-100 =PHL37039-11. It consists of two images, A (mR = 16.9) and B (mR = 19.1), separated by 2.2arcs at a redshift zq = 2.719. The lensing galaxy (mR~ 19, ZL~0.49) has also been found. It lies very near the line connecting the two QSO images, ~0.8 arc s from the fainter one. Application of gravitational optometry to this system leads to a value M0~2.4×1011Msolar for the mass of the lensing galaxy and to δt~7 weeks for the most likely travel-time difference between the two light paths to the QSO (assuming H0= 75 km s-1 Mpc-1,q0 = 0). Title: Detection of interstellar CH and CH+ towards SN 1987A. Authors: Magain, P.; Gillet, D. Bibcode: 1987A&A...184L...5M Altcode: The authors report the detection of interstellar CH and CH+ towards supernova 1987A. For both of these molecules, one component is detected at a heliocentric velocity of about 280 km/s, corresponding to material inside the LMC. Some implications of the authors' results with regards to the H2-to-dust ratio are briefly discussed. Title: Interstellar calcium towards supernova 1987A in the Large Magellanic Cloud Authors: Magain, Pierre Bibcode: 1987Natur.329..606M Altcode: 1987Nat...329..606M We present high-resolution and high signal-to-noise spectra of interstellar calcium towards SN1987A in the Large Magellanic Cloud (LMC). They supplement previously published observations1,2 for Ca II and provide completely new results for the Ca I spectrum, in which eleven components are detected, not only at velocities corresponding to our Galaxy and the LMC, but also at intermediate velocities. Our spectra, that allow us to estimate the ionization balance in these interstellar clouds, provide some clues about their physical state and location. In particular, the components between 150 and 200 km s-1 show a much lower ionization degree than other components. This may be due to recent compression of the gas by a shock, possibly associated with a former supernova explosion. This interpretation would require the corresponding clouds to be located inside the LMC, indicating that at least some intermediate velocity components are not of halo origin. Title: On the interpretation of the CH cometary spectrum. Authors: Arpigny, C.; Zeippen, C. J.; Klutz, M.; Magain, P.; Hutsemekers, D. Bibcode: 1987ESASP.278..607A Altcode: 1987dsc..proc..607A A procedure to compute cometary spectra taking into account radiative processes and collisional effects is described. The populations of the rotational levels are determined by solving the statistical equilibrium equations at a certain number of locations within the coma (which can be modelled with n(R), T(R), v(R) laws) and the emerging intensity is then evaluated by integrating the emissions along the line of sight. Such a program was applied to the CH radical. The importance of collisions in exciting the lower rotational levels of CH is confirmed. Title: On the forbidden red lines of oxygen in comets. Authors: Arpigny, C.; Manfroid, J.; Magain, P.; Haefner, R. Bibcode: 1987ESASP.278..571A Altcode: 1987dsc..proc..571A Eighteen spectra of 8 different comets observed at high and medium resolution were analyzed in the 627 to 637 nm region to determine the contributions of the (OI) red doublet and of the various NH2 lines present in this wavelength interval. Results confirm that there exist appreciable variations not only in the (OI)/NH2 ratio, but also in the relative intensities of the NH2 features among themselves, therefore, it is not justified to derive the (OI) line flux from the 630.0 blend, as was done in previous low-resolution work, by assuming a fixed relative strength of the NH2 emission contained in this blend. Mapping of these emissions over the coma is recommended. Title: High Resolution Spectroscopy and Analysis of the C2(0,0) Band in Comet P/Halley Authors: Danks, A. C.; Lambert, D. L.; Sheffer, Y.; Arpigny, C.; Dossin, F.; Magain, P. Bibcode: 1987BAAS...19.1124D Altcode: No abstract at ADS Title: The missing opacity and the temperature calibration of solar-type stars. Authors: Magain, P. Bibcode: 1987A&A...181..323M Altcode: The novel temperature calibration of some color indices presented for G and F dwarfs is based on the IR flux method and extends the work of Saxner and Hammarback (1985) to the Population II stars. Attention is given to the discrepancy between theoretical and empirical temperature calibrations. It is suggested that the most straightforward interpretation of the disagreement between empirical colors and some model predictions is that of the 'missing opacity' due to a veil of faint metal lines, present in the blue and UV regions of the spectra of solar-type and cooler stars, but excluded from the model. Title: HD 151932 variability revisited. Authors: Vreux, J. M.; Magain, P.; Manfroid, J.; Scuflaire, R. Bibcode: 1987A&A...180L..17V Altcode: The observation of variations in the blue absorption component of the He I lines as well as in the Si IV 4089 emission line of HD 151932 is reported. Possible explanations for these variations are addressed, and it is concluded that none is satisfactory. The possibility of a periodicity in the variations is briefly considered. Title: Abundances of light elements in halo dwarfs : a re-analysis. Authors: Magain, P. Bibcode: 1987A&A...179..176M Altcode: The abundances of a few light elements in the atmospheres of halo dwarfs are redetermined on the basis of literature data reanalysed in an homogeneous way. It is shown that the scatter of the resulting Mg and Al abundances is strongly reduced and that no discrepancy remains between the abundances deduced from blue and red lines. Mg, Si and Ca show constant overabundances while the Al overdeficiency seems in agreement with the predictions of explosive carbon burning. Title: Photometric Observations of WR78 = HD 151932 Authors: Magain, P.; Vreux, J. M.; Manfroid, J. Bibcode: 1987IBVS.3022....1M Altcode: No abstract at ADS Title: BD +03 deg 740 - A new extreme metal-poor dwarf Authors: Magain, P. Bibcode: 1987Msngr..47...18M Altcode: The results of a preliminary analysis of BD +03 deg 740 are presented. The analysis was based on the blue spectrum which was obtained with an exposure time of 40 min, giving a good S/N ratio for this 9.8-mag star. Graphs are presented which reveal the extreme weakness of the metal lines in the spectrum. The analysis of BD +03 deg 740, which is the most metal-poor dwarf in which s element abundances have been determined, confirms the presence of secondary elements in the atmospheres of the extreme halo dwarfs. Title: Supernova 1987A in the Large Magellanic Cloud Authors: Cristiani, S.; Gouiffes, C.; Hanuschik, R.; Magain, P.; Dawe, J.; McNaught, R. H.; Beresford, T. Bibcode: 1987IAUC.4350....1C Altcode: 1987IAUC.4350....0C S. Cristiani and C. Gouiffes, European Southern Observatory; R. Hanuschik, Bochum University; and P. Magain, ESO, report: "Spectra taken at intermediate resolution (0.2-0.3 nm) between Mar. 14 and 22, with the spectrum scanner attached to the Bochum University 0.61-m telescope and with the ESO 1.5-m telescope at La Silla, showed changes in the P-Cyg profile of H-alpha. On Mar. 15, a weak bump at 647 nm appeared on the previously-very-smooth P-Cyg profile (near the bottom of the absorption) which developed in the following days, assuming a peaked structure and reaching the continuum level about Mar. 20. A comparison with previous spectra suggests that this is an additional emission feature. Spectra taken with the CAT 1.4-m telescope (resolution 80000) do not show smaller- scale structures. The precise wavelength of the relative maximum in the spectrum is 647.0 nm, followed by a minimum at 648.8 nm. The FWHM of the two features is 1.45 and 2.10 nm, respectively. If identified with H-alpha, the emission corresponds to a velocity of -4500 km/s. No corresponding structures have been observed in the P-Cyg profiles of H-beta and Ca 860-nm. Those observations suggest a distortion in the spherical symmetric outflow of the explosion, which can be confirmed by polarization observations of the H-alpha profile." Provisional photoelectric photometry by J. Dawe and R. H. McNaught with the Australian National University 0.61-m reflector at Siding Spring Observatory: Mar. 20.456 UT, V = 4.12, B-V = +1.58, U-B = +2.04. Further visual magnitude estimates: Mar. 19.39, 4.1 (McNaught); 19.52, 4.0 (T. Beresford, Adelaide, South Australia); 20.45, 4.0 (McNaught); 20.48, 3.9 (Beresford). Title: Supernova 1987A in the Large Magellanic Cloud Authors: Cristiani, S.; Gouiffes, C.; Hanuschik, R.; Magain, P.; Dawe, J.; McNaught, R. H.; Beresford, A. Bibcode: 1987IAUC.4350.....C Altcode: No abstract at ADS Title: Resolution of the [O I]+NH2 blend in comets. Authors: Arpigny, C.; Magain, P.; Manfroid, J.; Dossin, F.; Haefner, R. Bibcode: 1987LIACo..27..315A Altcode: No abstract at ADS Title: Very Low Upper Limits on the Strength of Interstellar Lithium Lines Toward Supernova 1987A Authors: Baade, D.; Magain, P. Bibcode: 1987ESOC...26..537B Altcode: 1987sn...work..537B No abstract at ADS Title: CES+CCD Observations of Interstellar Lines Towards Supernova 1987A Authors: Magain, P. Bibcode: 1987ESOC...26..533M Altcode: 1987sn...work..533M No abstract at ADS Title: High resolution spectroscopy with the E.S.O. Coudé Echelle Spectrometer. Authors: Magain, Pierre Bibcode: 1987LIACo..27...15M Altcode: 1987oahp.proc...15M Various applications of high resolution spectroscopy with the ESO Coude Echelle Spectrometer (CES) are discussed. The aim of this paper is not to present a complete survey of the CES capabilities, but to illustrate some possible applications, with emphasis on rather unusual aspects. In all the observations presented here, the CES has been used with the new short camera and a CCD detector (high resolution RCA SID 503, 640 x 1024 pixels, 15x15 microns each). Compared to the long camera and Reticon detector, this new combination represents an increase of efficiency of 2 to 3 magnitudes with only a moderate loss of resolving power. Title: Resolution of the (OI)+NH2 Blend in Comet P/halley Authors: Arpigny, C.; Magain, P.; Manfroid, J.; Dossin, F.; Danks, A. C.; Lambert, D. L. Bibcode: 1986ESASP.250c..81A Altcode: Spectra of P/Halley were taken at very high resolution (0.15A) to evaluate contamination of the forbidden oxygen doublet by NH2 features at low resolution. Comparison is made with other bright comets. Appreciable variations are found in the NH2/(OI) ratio and in the relative intensities of the NH2 emissions themselves. The accuracy obtained on the oxygen abundance derived from the (OI) lines is discussed. Mapping of these emissions over the coma is required to correctly remove any important NH2 contribution at low resolution. This should also provide information on the origin of the oxygen atoms in the 1D level. Title: Spectroscopy, Photometry and Direct Filter Imagery of Comet P/Halley Authors: Arpigny, C.; Dossin, F.; Manfroid, J.; Magain, P.; Danks, A. C.; Lambert, D. L.; Sterken, C. Bibcode: 1986Msngr..45....8A Altcode: 1986Msngr..45....8S Observational techniques and instrumentation applied in ground-based studies of the cometary coma during the post-perihelion phase of the recent passage of Comet Halley are summarized. Applications of a 1.5 m telescope equipped with a coude spectrograph for long slit investigations of spectral intensity distributions, a 1.4 m CAT, coude echelle spectrometer and reticon to evaluate the C-12/C-13 isotopic abundance ratio, and a 50 cm photometric telescope for narrow bandwidth spectroscopy are described. Finally, the 1.5 m Danish telescope, equipped with a CCD camera, collected high spatial resolution photographs of the various coma components when the comet was 0.42 AU from the sun. Title: Contribution functions and the depths of formation of spectral lines Authors: Magain, P. Bibcode: 1986A&A...163..135M Altcode: A rigorous expression is derived for the contribution function to the spectral line depression in a stellar atmosphere; this, in effect, gives the contribution of the different atmospheric layers to the formation of the line depression. This contribution function is the solution of the transfer equation for the line depression. It is the only appropriate distribution function for the computation of the depths of formation of spectral lines. It indicates, in contrast to some earlier contribution functions, that a faint spectral line is not necessarily formed in the same layers as the continuum. The response function of the line depression to a given perturbation is briefly discussed. Title: Spectroscopic analysis of extreme metal-poor ''dwarfs''. II. Improvedmodel atmospheres and detailed abundances. Authors: Magain, P. Bibcode: 1985A&A...146...95M Altcode: High resolution spectrophotometric data were obtained for the stellar objects HD 19445 and HD 140283. The spectra gathered were well-matched by model stellar atmospheres for the continuous flux and Fe I excitation equilibrium. HD 19445 was identified as a dwarf star and HD 140283 as a subgiant. Abundance analyses indicated an Fe abundance lower than previously estimated, oxygen overabundant relative to C and Fe, Mg, Si and Ca overabundant relative to Fe, and deficiencies of Al and Mn. Sr was overabundant relative to Ba. The abundance discrepancies are in disagreement with the standard nucleosynthesis model. Further such spectroscopic data are needed to develop accurate galactic chemical evolution models. Title: A comment on systematic errors in determinations of microturbulent velocities Authors: Magain, P. Bibcode: 1984A&A...134..189M Altcode: It is shown that the usual method of microturbulent velocity determination from the "abundance versus equivalent width" plot leads to a systematic overestimate of the microturbulent velocity when the observd equivalent widths are affected by random errors. This overestimate is due to the correlation between errors in observed equivalent widths and in line abundances. This error rises rapidly with decreasing quality of the observational material and may be avoided by using theoretical equivalent widths instead of observed ones as abscissa of the "abundance versus equivalent width" plot. Title: Spectroscopic analysis of extreme metal-poor 'dwarfs'. I. Observational material, Fe lines, and model atmospheres. Authors: Magain, P. Bibcode: 1984A&A...132..208M Altcode: Fe lines are analysed in the spectra of the two extreme metal-poor stars MD 19445 and MD 140283 on the basis of new observational material. It is shown that the use of accurate equivalent widths and very accurate oscillator strengths improves significantly the quality of the analysis. In particular, these stars are found to be more metal-deficient than precedingly thought. This result may imply a significant revision of the adopted abundance scale. It is shown that differential analyses of such stars relative to the Sun are subject to important systematic errors due to the very large difference between the stellar and solar equivalent widths. Finally, the temperature criteria are analysed and it is argued that the criteria linked to deep atmospheric layers, such as the B - V colour or the hydrogen line wings, should not be used to select a model representing satisfactorily the line-forming layers. Title: Etude détaillée d'étoiles froides pauvres en métaux Title: Etude détaillée d'étoiles froides pauvres en métaux Title: Detailed study of cold metal-poor stars; Authors: Magain, Pierre Bibcode: 1984PhDT.......162M Altcode: No abstract at ADS Title: A Test of the Planck-Larkin Partition Function Authors: Magain, P. Bibcode: 1984LIACo..25..234M Altcode: 1984trss.conf..234M; 1984tpss.conf..234M No abstract at ADS Title: The A1/Mg abundance ratio in halo stars. Authors: Arpigny, C.; Magain, P. Bibcode: 1983A&A...127L...7A Altcode: The Al to Mg abundance ratio is redetermined in two extreme metal-poor stars, HD 19445 and HD 140283, on the basis of accurate spectral material. It is found that: (1) one of the two lines used for the Al abundance determination is blended by CH lines; (2) no anomalous difference appears between the hotter and the cooler star, both showing an Al overdeficiency; (3) the observations are in fair agreement with predictions from the theory of explosive carbon burning. Title: The missing UV opacity and the colours of solar-type stars. Authors: Magain, P. Bibcode: 1983A&A...122..225M Altcode: A simple method is proposed to take into account the "missing UV opacity" in solar-type stars. It is shown that the mere inclusion of that UV opacity through a very simple formula is sufficient to bring the theoretical colours in agreement with observed ones for stars of different metal abundances and belonging to the spectral range from mid-F to late-G. Synthetic colours computed in the Geneva and UBV systems reproduce the various observed relations satisfactorily. The relations based on these colours allow reliable estimates of effective temperatures, surface gravities and metal abundances of stars. In addition, solar colours are obtained and three more solar twin candidates are proposed.