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.

A bright X-ray transient was detected by Chandra on 2002 June 2 with a series of 5 HRC-I snapshots. The new source CXOU J004154.6+405648 (R.A.=00h41m54s.64, Dec...

Chandra observations on Jan 16, 2002 surveyed M31 with a series of 5 short (1ks) HRC images. Preliminary analysis yields the following info on new transients...

A bright X-ray transient in M31 was detected in a 5000-sec Chandra ACIS-I observation on 2001 Aug 31.54 UT. The new transient (CXOU J004305.5+411703) is located...

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...

One of the most important features in active galactic nuclei (AGN) is the variability of their emission. Variability has been discovered at X-ray, UV, and radio...

Active galactic nuclei (AGN) are powered by energetic phenomena which cannot be attributed to stars. Among AGN, several objects can be described by the unified...