Search Publications

Temporal variations in the evaporating atmosphere of the exoplanet HD 189733b
DOI: 10.1051/0004-6361/201219363 Bibcode: 2012A&A...543L...4L

Ehrenreich, D.; Lecavelier des Etangs, A.; Bourrier, V. +8 more

Atmospheric escape has been detected from the exoplanet HD 209458b through transit observations of the hydrogen Lyman-α line. Here we present spectrally resolved Lyman-α transit observations of the exoplanet HD 189733b at two different epochs. These HST/STIS observations show for the first time that there are …

2012 Astronomy and Astrophysics
eHST 229
CAIXA: a catalogue of AGN in the XMM-Newton archive. III. Excess variance analysis
DOI: 10.1051/0004-6361/201118326 Bibcode: 2012A&A...542A..83P

Bianchi, S.; Ponti, G.; Guainazzi, M. +4 more

Context. We report on the results of the first XMM-Newton systematic "excess variance" study of all the radio quiet, X-ray un-obscured AGN. The entire sample consist of 161 sources observed by XMM-Newton for more than 10 ks in pointed observations, which is the largest sample used so far to study AGN X-ray variability on time scales less than a da…

2012 Astronomy and Astrophysics
XMM-Newton 218
In-orbit performance of Herschel-HIFI
DOI: 10.1051/0004-6361/201015120 Bibcode: 2012A&A...537A..17R

de Graauw, Th.; Braine, J.; Martín-Pintado, J. +96 more


Aims: In this paper the calibration and in-orbit performance of the Heterodyne Instrument for the Far-Infrared (HIFI) is described.
Methods: The calibration of HIFI is based on a combination of ground and in-flight tests. Dedicated ground tests to determine those instrument parameters that can only be measured accurately using controlled…

2012 Astronomy and Astrophysics
Herschel 207
The Galactic WC stars. Stellar parameters from spectral analyses indicate a new evolutionary sequence
DOI: 10.1051/0004-6361/201117830 Bibcode: 2012A&A...540A.144S

Sander, A.; Hamann, W. -R.; Todt, H.

Context. The life cycles of massive stars from the main sequence to their explosion as supernovae or gamma ray bursts are not yet fully clear, and the empirical results from spectral analyses are partly in conflict with current evolutionary models. The spectral analysis of Wolf-Rayet stars requires the detailed modeling of expanding stellar atmosp…

2012 Astronomy and Astrophysics
IUE 206
Simultaneous Planck, Swift, and Fermi observations of X-ray and γ-ray selected blazars
DOI: 10.1051/0004-6361/201117825 Bibcode: 2012A&A...541A.160G

Tagliaferri, G.; Bonaldi, A.; Bonavera, L. +92 more

We present simultaneous Planck, Swift, Fermi, and ground-based data for 105 blazars belonging to three samples with flux limits in the soft X-ray, hard X-ray, and γ-ray bands, with additional 5GHz flux-density limits to ensure a good probability of a Planck detection. We compare our results to those of a companion paper presenting simultaneous Pla…

2012 Astronomy and Astrophysics
Planck 206
A chemical model for the atmosphere of hot Jupiters
DOI: 10.1051/0004-6361/201219310 Bibcode: 2012A&A...546A..43V

Agúndez, M.; Hersant, F.; Dobrijevic, M. +5 more

Context. The atmosphere of hot Jupiters can be probed by primary transit and secondary eclipse spectroscopy. Owing to the intense UV irradiation, mixing, and circulation, their chemical composition is maintained out of equilibrium and must be modeled with kinetic models.
Aims: Our purpose is to release a chemical network and the associated ra…

2012 Astronomy and Astrophysics
eHST 202
X-ray variability of 104 active galactic nuclei. XMM-Newton power-spectrum density profiles
DOI: 10.1051/0004-6361/201219008 Bibcode: 2012A&A...544A..80G

Vaughan, S.; González-Martín, O.

Context. Active galactic nuclei (AGN), powered by accretion onto supermassive black holes (SMBHs), are thought to be scaled up versions of Galactic black hole X-ray binaries (BH-XRBs). In the past few years evidence of such correspondence include similarities in the broadband shape of the X-ray variability power spectra, with characteristic bend t…

2012 Astronomy and Astrophysics
XMM-Newton 200
Enhanced star formation rates in AGN hosts with respect to inactive galaxies from PEP-Herschel observations
DOI: 10.1051/0004-6361/201118266 Bibcode: 2012A&A...540A.109S

Berta, S.; Magnelli, B.; Nordon, R. +35 more

We compare the average star formation (SF) activity in X-ray selected AGN hosts with a mass-matched control sample of inactive galaxies, including both star forming and quiescent sources, in the 0.5 < z < 2.5 redshift range. Recent observations carried out by PACS, the 60-210 µm photometric camera on board the Herschel Space Observator…

2012 Astronomy and Astrophysics
Herschel 192
A far-infrared survey of bow shocks and detached shells around AGB stars and red supergiants
DOI: 10.1051/0004-6361/201117910 Bibcode: 2012A&A...537A..35C

Blommaert, J. A. D. L.; Jorissen, A.; Ottensamer, R. +16 more


Aims: Our goal is to study the different morphologies associated to the interaction of the stellar winds of AGB stars and red supergiants with the interstellar medium (ISM) to follow the fate of the circumstellar matter injected into the interstellar medium.
Methods: Far-infrared Herschel/PACS images at 70 and 160 µm of a sample of…

2012 Astronomy and Astrophysics
Herschel 191
The dust scaling relations of the Herschel Reference Survey
DOI: 10.1051/0004-6361/201118499 Bibcode: 2012A&A...540A..52C

Clements, D. L.; Ciesla, L.; Boquien, M. +23 more

We combine new Herschel/SPIRE sub-millimeter observations with existing multiwavelength data to investigate the dust scaling relations of the Herschel Reference Survey, a magnitude-, volume-limited sample of ~300 nearby galaxies in different environments. We show that the dust-to-stellar mass ratio anti-correlates with stellar mass, stellar mass s…

2012 Astronomy and Astrophysics
Herschel 184