Optical Microvariability in Quasars: Spectral Variability
We present a method that we developed to discern where the optical microvariability (OM) in quasars originates: in the accretion disk (related to thermal...
We present results from a project focused on searching optical microvariabilty (also known as ``intra-night'' variability) in type 2 - obscured - quasars...
Optical novae: the major class of supersoft X-ray sources in M 31
We searched for X-ray counterparts of optical novae detected in M 31 and M 33. We combined an optical nova catalogue from the WeCAPP survey with optical novae...
Optical observations of Dwingeloo 1, a nearby barred spiral galaxy behind the Milky Way
We present new optical observations of the nearby barred spiral galaxy Dwingeloo 1 (Dw1) obtained with the Isaac Newton, William Herschel and Wise telescopes...
Observations of the gravitational lens system 0957+561A, B in the R band are presented in this Letter. The observations, taken with the 82 cm IAC-80 telescope...
Optical Properties of the Ultraluminous X-Ray Source Holmberg IX X-1 and Its Stellar Environment
Holmberg IX X-1 is an archetypal ultraluminous X-ray source (ULX). Here we study the properties of the optical counterpart and of its stellar environment using...
Optical Recombination Lines of Heavy Elements in Giant Extragalactic H II Regions
We present high-resolution observations of the giant extragalactic H II regions NGC 604, NGC 2363, NGC 5461, and NGC 5471, based on observations taken with the...