Context. The solar spectrum is a primary reference for the study of physical processes in stars and their variation during activity cycles. High resolution spectra of the Sun are easily obtained from spatially selected regions of the solar disk, while those taken over the integrated disk are more problematic. However, a proxy can be obtained by

Galactic black holes release an unknown fraction of their accreting matter and energy in the form of collimated outflows (or jets) that travel into the surrounding medium. Black Hole X-ray Binaries (BHXBs) are the essential laboratories for understanding the overall physics of the accretion process in these systems, and have provided us with a

The Owl Nebula (NGC 3587) is a double shell nebula. An additional faint halo is recently found in interference filter CCD images (Kwitter, Chu, & Downes 1992, in IAU Symp. 155). To confirm and to determine the physical nature of this halo, we have obtained spectra of the Owl Nebula with the IDS spectrograph on the INT 2.5m telescope at La Palma

The cosmological numerical simulations tell us that accretion of external metal-poor gas drives star formation (SF) in galaxy disks. One the best pieces of observational evidence supporting this prediction is the existence of low-metallicity star-forming regions in relatively high-metallicity host galaxies. The SF is thought to be fed by metal-poor

The structure and evolution of the Milky Way is imprinted on the kinematics, chemical abundances, and spatial distribution of its constituent stars. In the past, samples of stars in the halo and thick disk have primarily been selected either on the basis of their kinematics (e.g., proper-motion selection), their distinct abundances (e.g., objective

The optical afterglow spectrum of GRB 050401 (at z=2.8992+/-0.0004) shows the presence of a damped Lyα absorber (DLA), with logNHI=22.6+/-0.3. This is the highest column density ever observed in a DLA and is about 5 times larger than the strongest DLA detected so far in any QSO spectrum. From the optical spectrum, we also find a very large Zn