Following our recent report on the transition to quiescence of the transient neutron star low-mass X-ray binary XTE J1701-407 (ATel #3604), we continued to...

We have analyzed the X-ray lightcurve of the star CI Cam, the optical counterpart of the X-ray transient XTE J0421+56 using data from XMM-Newton. Our motivation...

M31 is one of the best studied galaxies. At a distance of 700 kpc, it provides us with an opportunity to study the global properties of a galaxy which is...

NGC 2808 was observed with the Chandra X-ray Observatory and the Chandra Advanced CCD Imaging Spectrometer-Imager (ACIS-I) at its focus on 2007 June 19-21 (28...

Variability in active galactic nuclei (AGN) has been discovered at X-ray, UV, and radio frequencies on timescales from hours to years, being one of their most...

Although variability is a general property of AGN, and in LINERs variations in timescales of months/years have been found for some objects, it is not clear how...

The author reports on a study of the x-ray spectral variability of 37 low-mass x-ray binaries (LMXRB). The sample studied consists of all LMXRB which were...

We present results on the X-ray spectral analysis of the XMM-Newton deep surveys on the Lockman Hole and Chandra Deep Field South fields. Using the results of...

The neutron star X-ray transient 4U 1608-52 is often in a state of outburst (e.g. ATel #1113); the Swift/BAT light curve shows three clear outburst peaks so far...