We present Hα and [OIII] (5007 Å) images of the nebula powered by the jet of the black hole candidate and microquasar Cygnus X-1, observed with the 2.5-m Isaac...

We have studied the Lyα, Hβ, Hα, and Mg II λ2798 line profiles of the Seyfert 1 galaxy III Zw 2. The shapes of these broad emission lines show evidence of a...

A long flux enhancement, with an exponential decay time of 86 min, is detected in 4U 1735-44 with the BeppoSAX Wide Field Cameras. We argue that this is a type...

We present an optical spectroscopic study of the black hole X-ray transient V4641 Sgr (=SAX J1819.3-2525) covering the 1999, 2002, and 2004 outbursts. The...

We present time-resolved spectroscopy and circular spectropolarimetry of the SW Sex star RXJ1643.7+3402. We find significant polarization levels exhibiting a...

A NLTE-analysis is presented of high S/N spectra of the optical component of the standard massive X-ray binary Vela X-1. In combination with the orbital...

We present the first detection of the mass donor star in the prototype X-ray binary Scorpius X-1. Phase-resolved spectroscopy revealed narrow emission line...

Cygnus X-2 is one of the brightest and longest known X-ray sources. We present high-resolution optical spectroscopy of Cyg X-2 obtained over 4 yr, which gives...

We present a dynamical study of the intermediate polar cataclysmic variable YY Dra based on time-series observations in the K band, where the donor star is...