The ultraluminous X-ray source (ULX) Holmberg II X-1 has been observed over four months in 2009/2010 by the Swift observatory. The source luminosity varied by a factor of up to 14, reaching a maximum 0.3-10 keV luminosity of ~3.0 × 1040 erg s-1. The spectral properties do not vary much over these four months, with only a slight monotonic increase

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. Preliminary analysis allows us to report the following concerning possible X-ray transients within M31. A new source CXOU J004428.4+415628 (RA=00:44:28.4, DEC=+41:56:28.1, J2000), near the NE spiral

We combine bright XMM-Newton data with the Chandra Deep Field South observations to explore the behavior of the intrinsic AGN absorption, as a function of redshift and luminosity. Our sample consists of 359 sources selected in the hard 2-8 keV band, spanning the flux range 6 × 10-16-3 × 10-13 erg~cm-2~s-1 with a high rate of spectroscopic or

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 600 ks of good EPIC-pn data. We have spectra with good signal to noise (>500 source counts) for all objects down to 0.2

Orbital properties of hot Jupiters depend on the temperature and rotation rate of their host stars. These observed correlations provide some of the very few constraints on their dynamical evolution. However, almost all the objects available to such studies orbit around relatively slow rotators, with stellar rotation periods usually several times

IAUC 7542 available at Central Bureau for Astronomical Telegrams.