When averaged over large scales, star formation in galaxies is observed to follow the empirical Kennicutt-Schmidt (KS) law for surface densities above a constant threshold. While the observed law involves surface densities, theoretical models and simulations generally work with volume density laws (i.e. Schmidt laws). We derive analytic relations

We report on optical and near-infrared observations obtained during and after the 2004 December discovery outburst of the X-ray transient and accretion-powered millisecond pulsar IGR J00291+5934. Our observations monitored the evolution of the brightness and the spectral properties of IGR J00291+5934 during the outburst decay toward quiescence. We

Aims:The nature of S Ori 70 (S Ori J053810.1-023626), a faint mid-T type object found towards the direction of the young σ Orionis cluster, is still under debate. We intend to find out whether it is a field brown dwarf or a 3-Myr old planetary-mass member of the cluster. Methods: We report on near-infrared {JHK}s and mid-infrared [3.6] and [4.5]

Context: Multi-conjugate adaptive optics (MCAO) combine the advantages of both standard adaptive optics, which provide high contrast and high spatial resolution, and of wide field imaging (≈1'). Up to recently, MCAO for astronomy was limited to laboratory experiments. In this paper, we present the first scientific results obtained with the first

Aims:We study the contradictory magnetic field strength distributions retrieved from independent analyses of spectropolarimetric observations in the near-infrared (1.56 μm) and in the visible (630 nm) spectral ranges in internetwork regions. Methods: To solve this apparent controversy, we present simultaneous and co-spatial 1.56 μm and 630 nm

Aims:We study the properties and nature of extremely red galaxies (ERO, R-K≥5.6) found behind two lensing clusters and compare them with other known galaxy populations. Methods: New HST/ACS, Spitzer (IRAC and MIPS), and Chandra/ACIS observations of the two lensing clusters Abell 1835 and AC114 have been obtained, combined with our earlier optical