Related papers: X 1908+075: An X-ray Binary with a 4.4 day Period

New generation TeV gamma-ray telescopes have discovered many new sources, including several enigmatic unidentified TeV objects. HESS J0632+057 is a particularly interesting unidentified TeV source since: it is a point source, it has a…

SGR 1833-0832 was discovered on 2010 March 19 thanks to the Swift detection of a short hard X-ray burst and follow-up X-ray observations. Since then, it was repeatedly observed with Swift, Rossi X-ray Timing Explorer, and XMM-Newton. Using…

Emission from Active Galactic Nuclei is known to vary strongly over time over a wide energy band, but the origin of the variability and especially of the inter-band correlations is still not well established. Here we present the results of…

Aims. X1908+075 is a supergiant X-ray binary (SgXB) composed of an evolved OB star and a neutron star (NS) in a 4.4-day orbit. We aim to characterize the stellar wind, constrain the system geometry, and investigate the origin and…

The metal rich globular cluster RZ 2109 in the massive Virgo elliptical galaxy NGC 4472 (M49) harbours the ultra luminous X-ray source XMMU 122939.7+075333. Previous studies showed that this source varies between bright and faint phases on…

We present an investigation of long-term modulation in the X-ray light curves of five little-studied candidate high-mass X-ray binaries using the Swift Burst Alert Telescope. IGR J14488-5942 and AX J1700.2-4220 show strong modulation at…

Models for the characteristically soft X-ray spectrum of the compact X-ray source V1498 Aql (=4U 1957+11) have ranged from optically thick Comptonization to multicolor accretion disk models. We critically examine the X-ray spectrum of V1408…

The number of known Be/X-ray binaries in the Large Magellanic Cloud is small compared to the observed population of the Galaxy or the Small Magellanic Cloud. The discovery of a system in outburst provides the rare opportunity to measure its…

The study of the X-ray emission from massive binaries constitutes a relevant approach to investigate shock physics. The case of short period binaries may turn out to be quite challenging, especially in very asymmetric systems where the…

Rossi X-ray Timing Explorer All-Sky Monitor observations of the X-ray source 4U2206+54, previously proposed to be a Be star system, show the X-ray flux to be modulated with a period of approximately 9.6 days. If the modulation is due to…

A long (155 hours) ASCA observation was performed of two ultra luminous compact X-ray sources, Source 1 and Source 2, in the spiral galaxy IC 342. While Source 1 that was in a hard spectral state varied little, Source 2 that was in its soft…

We present X-ray light curves of Cygnus X-3 as measured by the recently launched AstroSat satellite. The light curve folded over the binary period of 4.8 hours shows a remarkable stability over the past 45 years and we find that we can use…

LS I+61303 is one of the few high-mass X-ray binaries that have been recently observed at TeV and GeV energies. Here we investigate the hard X-ray spectral and timing properties of this source using the IBIS/ISGRI instrument on-board the…

We present a catalog of hard X-ray sources detected in the first 105 months of observations with the Burst Alert Telescope (BAT) coded mask imager on board the Swift observatory. The 105 month Swift-BAT survey is a uniform hard X-ray…

We present initial results from an exploratory X-ray monitoring project of two groups of comparably luminous radio-quiet quasars (RQQs). The first consists of four sources at 4.10 <= z <= 4.35, monitored by Chandra, and the second is a…

Ultra-luminous X-Ray Objects are off-nucleus point sources with $L_X=10^{39}$-$10^{41}$ erg/s but the nature of such systems are largely unidentified. Here we report a 2.1 hour period observed in a Chandra ACIS observation for ULX M51 X-7,…

We present preliminary results of observations of X-ray pulsar SAX J2103.5+4545 with INTEGRAL observatory in Dec 2002. Maps of this sky region in energy bands 3-10, 15-40, 40-100 and 100-200 keV are presented. The source is significantly…

GRS 1915+105 is observed in an 'obscured' phase since May 2019, exhibiting steady and low X-ray luminosities, while being intervened by sporadic re-brightenings. In this work, we perform a comprehensive and wide-band analysis of the…

This work is devoted to the study of the broadband 0.8-79 keV spectral and timing properties of the poorly studied X-ray pulsar XTE J1859+083 during its 2015 outburst based on the data from the NuSTAR and Swift observatories. We show that…

We present a timing and spectral analysis of the variable X-ray source 3A 1954+319. Our analysis is mainly based on an outburst serendipitously observed during INTEGRAL Key Program observations of the Cygnus region in 2008 fall and on the…