Optical novae have recently been identified as the major class of supersoft X-ray sources in M 31 based on ROSAT and early XMM-Newton and Chandra observations. This paper reports on a search for X-ray counterparts of optical novae in M 31 based on archival Chandra HRC-I and ACIS-I as well as XMM-Newton observations of the galaxy center region

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 months after the XMM-Newton observation) for two distinct exposures of 46 and 11 kiloseconds (ks). (1 data file).

Compact binary millisecond pulsars with main-sequence donors, often referred to as "redbacks," constitute the long-sought link between low-mass X-ray binaries and millisecond radio pulsars and offer a unique probe of the interaction between pulsar winds and accretion flows. We present a systematic study of eight nearby redbacks, using more than 100

A recent merger of two supermassive black holes (BH) or the presence of a second active BH in the galactic nucleus are two of the main scenarios proposed to explain the X-shaped morphology observed in X-shaped radio galaxies. We test these scenarios by studying the BH mass, radio and optical luminosity, starburst history and dynamic age of radio

This paper presents the results of a detailed X-ray spectral analysis of a sample of 123 X-ray sources detected with XMM-Newton in the Lockman Hole field. This is the deepest observation carried out with XMM-Newton with more that 600ks of good EPIC-pn data. We have spectra with good signal to noise (>500 source counts) for all objects down to 0.2

X-ray sources at intermediate fluxes (a few x10-14erg/cm a sky density of ~100deg-2 are responsible for a significant fraction of the cosmic X-ray background at various energies below 10keV. The aim of this paper is to provide an unbiased and quantitative description of the X-ray source population at these fluxes and in various X-ray energy bands