We have computed the K-correction for emission lines formed on the irradiated face of the companion stars in X-ray binaries. Our results, combined with the detection of high excitation emission lines arising from the donor star can provide the first mass determinations for either neutron stars or black holes in active Low Mass X-ray Binaries (LMXBs

We present a complete spectroscopic survey of 2414 2MASS-selected blue horizontal branch (BHB) candidates selected over 4300 deg2 of the sky. We identify 655 BHB stars in this non-kinematically selected sample. We calculate the luminosity function of field BHB stars, and find evidence for very few hot BHB stars in the field. The BHB stars located

We have conducted an extensive observational campaign of SWIFT J1753.5-0127 over the last year, since its bright our-burst episode in 2005. Using long time baseline optical photometry, we have found a new period suggestive of orbital modulation with a period of 3.2 h, we have simultaneous multi-band photometry, and high-frequency multi-band

Context: A variety of formation scenarios have been proposed to explain the diversity of properties observed in bulges. Studying their intrinsic shape can help to constrain the dominant mechanisms at the epochs of their assembly. Aims: The structural parameters of a magnitude-limited sample of 148 unbarred S0-Sb galaxies were derived in order to

We present VRIJHK photometry, and optical and near-infrared spectroscopy, of the heavily extinguished Type Ia supernova (SN Ia) 2002cv, located in NGC 3190, which is also the parent galaxy of the SN Ia 2002bo. SN 2002cv, not visible in the blue, has a total visual extinction of 8.74 +/- 0.21 mag. In spite of this, we were able to obtain the light

We present the first simultaneous radio, X-ray, ultraviolet, and optical spectroscopic observations of the M8.5 dwarf TVLM 513-46546, with a duration of 9 hr. These observations are part of a program to study the origin of magnetic activity in ultracool dwarfs, and its impact on chromospheric and coronal emission. Here we detect steady quiescent