Related papers: XTE J1901+014 - the First Low-Mass Fast X-ray Tran…

In the course of the XMM-Newton survey of the Small Magellanic Cloud (SMC), a region to the east of the emission nebula N19 was observed in November 2009. To search for new candidates for high mass X-ray binaries the EPIC PN and MOS data of…

We report the result of an XMM-Newton observation of the black-hole X-ray transient XTE J1650-500 in quiescence. The source was not detected and we set upper limits on the 0.5-10 keV luminosity of 0.9e31-1.0e31 erg/s (for a newly derived…

Fast X-ray Transients (FXTs) are X-ray flares with a duration ranging from a few hundred seconds to a few hours. Possible origins include the tidal disruption of a white dwarf by an intermediate-mass black hole, a supernova shock breakout,…

SWIFT J1626.6-5156 is an X-ray pulsar that was discovered in December 2005 during an X-ray outburst. Although the X-ray data suggest that the system is a high-mass X-ray binary, very little information exists on the nature of the optical…

We report on observations aimed at searching for flux variations from the proposed IR counterpart of the Anomalous X-ray Pulsar XTE J1810-197. These data, obtained in March 2004 with the adaptive optics camera NAOS-CONICA at the ESO VLT,…

(abridged) We analyzed the archived XMM-Newton observation of the poorly studied low-mass X-ray binary XTE J1710-281 performed in 2004 that covered one orbital period of the system (3.8 hr). The source shows dips as well as eclipses, hence…

We report observations which confirm the identity of the optical/IR counterpart to the Rossi X-ray Timing Explorer transient source XTE J0111.2-7317. The counterpart is suggested to be a B0-B2 star (luminosity class III--V) showing an IR…

We present the first X-ray polarimetric measurement of the neutron star low-mass X-ray binary system AX J1745.6-2901 conducted by the Imaging X-ray Polarimetry Explorer (IXPE) satellite. This transient source, located within $ \sim $1.5' of…

We present optical and infrared observations of the soft X-ray transient (SXT) XTE J2012+381 and identify the optical counterpart with a faint red star heavily blended with a brighter foreground star. The fainter star is coincident with the…

After about 16 years since its first outburst, the transient neutron star low-mass X-ray binary XTE J1701$-$462 turned on again in September 2022, allowing for the first study of its X-ray polarimetric characteristics by a dedicated…

We present a study of the X-ray source NGC 2403 XMM4 (4XMM J073702.2+653934) based on 20 years of archival observations with XMM-Newton, Chandra, Swift and NuSTAR. Although it has previously been classified as an ultraluminous X-ray source…

Pulsations from the high mass X-ray binary AXJ1910.7+0917 were discovered during Chandra observations performed in 2011 (Israel et al. 2016). We report here more details on this discovery and discuss the source nature. The period of the…

We present the first results of our X-ray monitoring campaign on a 1.7 square degree region centered on Sgr A* using the satellites XMM-Newton and Chandra. The purpose of this campaign is to monitor the behavior (below 10 keV) of X-ray…

The X-ray source RX J004717.4-251811 in the nearby starburst galaxy NGC 253 was found to undergo changes from a low to a high state twice, during an XMM-Newton EPIC observation in December 2000 and also during a Chandra observation one year…

We present the XMM-Newton and the optical-VLT spectra along with the optical and the near-infrared photometric data of one of the brightest X-ray (F(2-10 keV)~1e-13 erg/s cm^2) extremely red objects (R-K>=5) discovered so far. The source,…

SAX J1711.6-3808 is an X-ray transient in the Galactic bulge that was active from January through May of 2001 and whose maximum 1-200 keV luminosity was measured to be 5X10-9 erg/s/cm2 which is less than ~25% of the Eddington limit, if…

A blue and variable optical counterpart of the X-ray transient XTE J0929-314 was identified on 2002 May 1. We conducted frequent BVRI broadband photometry on this object using the Mt Canopus 1-m telescope during May and June until it had…

The fourth transient accreting millisecond pulsar XTE J1807-294 was observed during its February/March 2003 outburst by INTEGRAL, partly simultaneously with the XMM-Newton and RXTE satellites. We present here the first study of the 0.5-200…

Context. The discovery of the unique source HESS J1507-622 in the very high energy (VHE) range (100 GeV-100 TeV) opened new possibilities to study the parent population of ultra-relativistic particles found in astrophysical sources and…

We report on the BeppoSAX/WFC observation of a strong type-I X-ray burst from the recently discovered transient source SAX J1810.8-2609. The observed event showed evidence of photospheric radius expansion due to super-Eddington burst…