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...

The ROSAT X-ray observations were carried out at three different epochs between 1992 and 1996. Two PSPC (called "A" and "B") and one HRI ("H") observations were...

IAUC 7291 available at Central Bureau for Astronomical Telegrams.

IAUC 7498 available at Central Bureau for Astronomical Telegrams.

On Nov 19, 2001, The Chandra X-ray Observatory surveyed M31 with 5 overlapping very short (1ks) HRC exposures and a single short (5ks) ACIS-S exposure...