Relativistic plasma jets are observed in many systems that host accreting black holes. According to theory, coiled magnetic fields close to the black hole...

We report the detection of an orbital, ellipsoidal modulation at a period of 16.8h for V2107 Oph (Nova Ophiuchi 1977, H1705-25), from R-band photometry. From...

We present the first optical observations of the soft X-ray transient Nova Vela 1993, taken during quiescence in 1995 and 1996. From the R-band photometry with...

We present the first infrared ellipsoidal study of a low-mass X-ray binary system, and hence measure the mass of the neutron star. Photometry of Cen X-4...

A new empirical calibration of the (B-V) index versus the three fundamental stellar parameters T(eff), (Fe/H), and log g is presented whose range of validity is...

Infrared observations are used to obtain effective temperatures with a 3-percent error for a sample of low main-sequence stars. The empirical calibration of...

We have compiled and studied photometric and spectroscopic data published in the literature of several star-forming regions and young open clusters (Orion...

A most desirable feature of a standard candle to estimate astronomical distances is robustness against changes in metallicity and age. It is argued that the...

The origin and evolution of cosmic magnetic fields as well as the influence of the magnetic fields on the evolution of galaxies are unknown. Though not without...