Search Publications
An absolutely calibrated Teff scale from the infrared flux method. Dwarfs and subgiants
Asplund, M.; Casagrande, L.; Meléndez, J. +2 more
Various effective temperature scales have been proposed over the years. Despite much work and the high internal precision usually achieved, systematic differences of order 100 K (or more) among various scales are still present. We present an investigation based on the infrared flux method aimed at assessing the source of such discrepancies and pin…
The X-ray to optical-UV luminosity ratio of X-ray selected type 1 AGN in XMM-COSMOS
Le Floc'h, E.; Jahnke, K.; Salvato, M. +29 more
We present a study of the X-ray to optical properties of a sample of 545 X-ray selected type 1 AGN, from the XMM-COSMOS survey, over a wide range of redshifts (0.04 < z < 4.25) and X-ray luminosities (40.6 ≤ Log L[2-10]~keV ≤ 45.3). About 60% of them are spectroscopically identified type 1 AGN, while the others have a reliable pho…
Evidence of the accelerated expansion of the Universe from weak lensing tomography with COSMOS
Benabed, K.; Simon, P.; Schrabback, T. +19 more
We present a comprehensive analysis of weak gravitational lensing by large-scale structure in the Hubble Space Telescope Cosmic Evolution Survey (COSMOS), in which we combine space-based galaxy shape measurements with ground-based photometric redshifts to study the redshift dependence of the lensing signal and constrain cosmological parameters. Af…
Evaporation of the planet HD 189733b observed in H I Lyman-α
Ehrenreich, D.; Udry, S.; Ferlet, R. +7 more
We observed three transits of the extrasolar planet HD 189733b in H i Lyman-α and in a few other lines in the ultraviolet with HST/ACS, in the search for atmospheric signatures. We detect a transit signature in the Lyman-α light curve with a transit depth of 5.05 ± 0.75%. This depth exceeds the occultation depth produced by the planetary disk alon…
Weighing simulated galaxy clusters using lensing and X-ray
Rasia, E.; Mazzotta, P.; Ettori, S. +5 more
Context. Among the methods employed to measure the mass of galaxy clusters, the techniques based on lensing and X-ray analyses are perhaps the most widely used; however, the comparison between these mass estimates is often difficult and, in several clusters, the results apparently inconsistent.
Aims: We aim at investigating potential biases i…
The Great Observatories Origins Deep Survey. VLT/VIMOS spectroscopy in the GOODS-south field: Part II
Popesso, P.; Cesarsky, C.; Dickinson, M. +10 more
Context. We present the full data set of the VIsible Multi-Object Spectrograph (VIMOS) spectroscopic campaign of the ESO/GOODS program in the Chandra Deep Field South (CDFS), which complements the FORS2 ESO/GOODS spectroscopic campaign.
Aims: The ESO/GOODS spectroscopic programs are aimed at reaching signal-to-noise ratios adequate to measure…
PHAT: PHoto-z Accuracy Testing
Ilbert, O.; Wolf, C.; Abdalla, F. B. +22 more
Context. Photometric redshifts (photo-z's) have become an essential tool in extragalactic astronomy. Many current and upcoming observing programmes require great accuracy of photo-z's to reach their scientific goals.
Aims: Here we introduce PHAT, the PHoto-z Accuracy Testing programme, an international initiative to test and compare different…
On the physical properties of z ≈ 6-8 galaxies
Schaerer, D.; de Barros, S.
Aims: We analyse the spectral energy distributions (SEDs) of the most distant galaxies discovered with the Hubble Space telescope and from the COSMOS survey and determine their physical properties, such as stellar age and mass, dust attenuation, and star-formation rate.
Methods: We use our SED fitting tool including the effects of nebula…
Deep imaging survey of young, nearby austral stars . VLT/NACO near-infrared Lyot-coronographic observations
Zuckerman, B.; Lagrange, A. -M.; Desidera, S. +10 more
Context. High contrast and high angular resolution imaging is the optimal search technique for substellar companions to nearby stars at physical separations larger than typically 10 AU. Two distinct populations of substellar companions, brown dwarfs and planets, can be probed and characterized. As a result, fossile traces of processes of formation…
The halos of satellite galaxies: the companion of the massive elliptical lens SL2S J08544-0121
Halkola, A.; Suyu, S. H.
Strong gravitational lensing by groups or clusters of galaxies provides a powerful technique to measure the dark matter properties of individual lens galaxies. We study in detail the mass distribution of the satellite lens galaxy in the group-scale lens SL2S J08544-0121 by modelling simultaneously the spatially extended surface brightness distribu…