The distance to the black hole binary GX 339-4 remains a topic of debate. We examine high-resolution optical spectra of the Na D lines resolving the velocity...

We report on the first 180 days of Rossi X-Ray Timing Explorer observations of the outburst of the black hole candidate IGR J17091-3624. This source exhibits a...

We report the detection of an orbital period decay of dot{P}=-1.83+/- 0.66 ms yr-1 in the black hole X-ray binary XTE J1118+480. This corresponds to a period...

MWC 656 is the first known Be/black hole (BH) binary system. Be/BH binaries are important in the context of binary system evolution and sources of detectable...

In this article we demonstrate that PKS J1037-2705 has a weak accretion flow luminosity, well below the Seyfert 1/QSO dividing line, weak broad emission lines...

Optical spectra were obtained of the optical counterpart of the high-latitude (b~=62deg) soft X-ray transient XTE J1118+480 near its quiescent state (R~=18.3)...

We have studied the host galaxies of a sample of radio-loud active galactic nuclei (AGNs) spanning more than 4 decades in the energy output of the nucleus. The...

We show that quasar microlensing magnification statistics induced by a population of point microlenses distributed according to a mass spectrum can be very well...

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...