Search Publications
Cosmic star-formation history from a non-parametric inversion of infrared galaxy counts
Elbaz, D.; Pichon, C.; Le Borgne, D. +1 more
Aims: This paper aims at providing new conservative constraints on the cosmic star-formation (SF) history from the empirical modeling of recent observations in the mid and far infrared.
Methods: We present a new empirical method based on a non-parametric inversion technique. It primarily uses multi-wavelength galaxy counts in the infrared and …
HD 174884: a strongly eccentric, short-period early-type binary system discovered by CoRoT
Auvergne, M.; Baudin, F.; Michel, E. +12 more
Accurate photometric CoRoT space observations of a secondary seismological target, HD 174884, led to the discovery that this star is an astrophysically important double-lined eclipsing spectroscopic binary in an eccentric orbit (e∼0.3), unusual for its short 3.65705° orbital period. The high eccentricity, coupled with the orientation of the binary…
The chemical abundance analysis of normal early A- and late B-type stars
Ryabchikova, T.; Fossati, L.; Alecian, E. +4 more
Context: Modern spectroscopy of early-type stars often aims at studying complex physical phenomena such as stellar pulsation, the peculiarity of the composition of the photosphere, chemical stratification, the presence of a magnetic field, and its interplay with the stellar atmosphere and the circumstellar environment. Comparatively less attention…
Magnetic flux emergence into the solar photosphere and chromosphere
Moreno-Insertis, F.; Tortosa-Andreu, A.
Aims: We model the emergence of magnetized plasma across granular convection cells and the low atmosphere, including layers up to the mid-chromosphere.
Methods: Three-dimensional numerical experiments are carried out in which the equations of MHD and radiative transfer are solved self-consistently. We use the MURaM code, which assumes local th…
WEBT multiwavelength monitoring and XMM-Newton observations of BL Lacertae in 2007-2008. Unveiling different emission components
Lee, C. -U.; Lähteenmäki, A.; Umana, G. +66 more
Context: BL Lacertae is the prototype of the blazar subclass named after it. Yet, it has occasionally shown a peculiar behaviour that has questioned a simple interpretation of its broad-band emission in terms of synchrotron plus synchrotron self-Compton (SSC) radiation.
Aims: In the 2007-2008 observing season we carried out a new multiwaveleng…
Gravitational potential and X-ray luminosities of early-type galaxies observed with XMM-Newton and Chandra
Matsushita, K.; Nagino, R.
Aims: We study the dark matter content in early-type galaxies and investigate whether X-ray luminosities of early-type galaxies are determined by the surrounding gravitational potential.
Methods: We derived gravitational mass profiles of 22 early-type galaxies observed with XMM-Newton and Chandra.
Results: Sixteen galaxies show constant or…
A spectroscopic survey of the youngest field stars in the solar neighbourhood. I. The optically bright sample
Motch, C.; Freire Ferrero, R.; Bouvier, J. +8 more
Aims: We present the first results of an ambitious ground-based observation programme conducted on 1-4 m class telescopes. Our sample consists of 1097 active and presumably young stars, all of them being optical (Tycho Catalogue) counterparts of ROSAT All-Sky Survey X-ray sources in the northern hemisphere. In this paper, we concentrate on the opt…
A new window of exploration in the mass spectrum: strong lensing by galaxy groups in the SL2S
Kneib, J. -P.; Sygnet, J. -F.; Willis, J. +21 more
The existence of strong lensing systems with Einstein radii covering the full mass spectrum, from ∼ 1-2 arcsec (produced by galaxy scale dark matter haloes) to >10 arcsec (produced by galaxy cluster scale haloes) have long been predicted. Many lenses with Einstein radii around 1-2 arcsec and above 10 arcsec have been reported but very few in be…
Searching for massive galaxies at z ≥ 3.5 in GOODS-North
Cimatti, A.; Daddi, E.; Rodighiero, G. +5 more
Aims: We constrain the space density and properties of massive galaxy candidates at redshifts of z≥3.5 in the Great Observatories Origin Deep Survey North (GOODS-N) field. By selecting sources in the Spitzer + IRAC bands, a sample highly complete in stellar-mass is assembled, including massive galaxies that are very faint in the optical/near-IR ba…
A self-consistent stellar and 3D nebular model of planetary nebula IC 418
Morisset, C.; Georgiev, L.
Aims: We present a coherent stellar and nebular model that reproduces observations of the planetary nebula IC 418. We aim to test whether a stellar model found to provide an optimal description of the stellar observations is able to satisfactory ionize the nebula and reproduce the nebular observations, a finding that is by no mean evident. This al…