Related papers: Detection of the second eclipsing high mass X-ray …

In this Paper we report on optical spectroscopic observations of the low-mass X-ray binary 2S 0921-630 obtained with the Very Large Telescope. We found sinusoidal radial velocity variations of the companion star with a semi-amplitude of…

We report on two optical candidates for the counterpart to an X-ray source in the SMC, 1WGA J0053.8-7226, identified as a serendipitous X-ray source from the ROSAT PSPC archive, and also observed by the Einstein IPC. Its X-ray properties,…

AX J1749.1-2733 is an unclassified transient X-ray source discovered during surveys by ASCA in 1993-1999. A multi-wavelength study in NIR, optical, X-rays and hard X-rays is undertaken in order to determine its nature. AX J1749.1-2733 is a…

We have observed the eclipsing low-mass X-ray binary MS1603.6+2600 with Chandra for 7 ksec. The X-ray spectrum is well fit with a single absorbed powerlaw with an index of ~2. We find a clear sinusoidal modulation in the X-ray lightcurve…

We report on a 40ks Chandra observation of the TeV emitting high mass X-ray binary HESS J0632+057 performed in February 2011 during a high-state of X-ray and TeV activity. We have used the ACIS-S camera in Continuos Clocking mode to search…

We report the association of the INTEGRAL source IGR J18027-2016 with the BeppoSAX source SAX J1802.7-2017. IGR J18027-2016 is seen to be a weak, persistent source by the IBIS/ISGRI instrument on board INTEGRAL with an average source count…

The dipping source XB 1916-053 is a compact binary system with an orbital period of 50 min harboring a neutron star. Using ten new {\it Chandra} observations and one {\it Swift/XRT} observation, we are able to extend the baseline of the…

We have carried out an in-depth study of low-mass X-ray binaries (LMXBs) detected in the nearby lenticular galaxy NGC 3115, using the Megasecond Chandra X-Ray Visionary Project observation (total exposure time 1.1 Ms). In total we found 136…

We have identified an X-ray transient (hereafter M15 X-3) in the globular cluster M15 from an archival Chandra grating observation. M15 X-3 appears at an X-ray luminosity of 6*10^{33} ergs/s with a spectrum consistent with an absorbed power…

During a search for coherent signals in the X-ray archival data of XMM-Newton, we discovered a modulation at 1.2 s in 3XMM J004301.4+413017 (3X J0043), a source lying in the direction of an external arm of M 31. This short period indicates…

We present a recent Chandra observation of the quiescent low-mass X-ray binary containing a neutron star, located in the globular cluster M30. We fit the thermal emission from the neutron star to extract its mass and radius. We find no…

The high-mass X-ray binary SMC X-1 is an eclipsing binary with an orbital period of 3.89 d. This system exhibits a superorbital modulation with a period varying between ~40 d and ~65 d. The instantaneous frequency and the corresponding…

The hard X-ray source 4U 2206+54 is a peculiar high mass X-ray binary with a main-sequence donor star. Recent X-ray observations suggested that the compact object in 4U 2206+54 may be a neutron star. The X-ray emission comes from the…

The new discovered short-period close binary star, XY LMi, was monitored photometrically since 2006. It is shown that the light curves are typical EW-type and show complete eclipses with an eclipse duration of about 80 minutes. By analyzing…

We obtained an optical spectrum of a star we identify as the optical counterpart of the M31 Chandra source CXO J004318.8+412016, because of prominent emission lines of the Balmer series, of neutral helium, and a He II line at 4686 Angstrom.…

We present X-ray observations of the high-inclination low-mass X-ray binary system X2127+119 (AC211) in the globular cluster M15 (NGC 7078). The observations consist of data acquired in 1996 with the RXTE satellite and in 1995 with the ASCA…

NSVS 02502726 has been known as a double-lined, detached eclipsing binary that consists of two low-mass stars. We obtained $BVRI$ photometric follow-up observations in 2009 and 2011 to measure improved physical properties of the binary…

EX Hya is one of the few double-lined eclipsing cataclysmic variables that allow an accurate measurement of the binary masses. We analyze orbital phase-resolved UVES/ VLT high resolution spectroscopic observations of EX Hya with the aims of…

We present X-ray and optical data of the newly discovered AM Her variable RX J1802.1+1804 = V884 Her. This X-ray source was observed in the ROSAT All-Sky-Survey in September 1990 and subsequently discovered as a highly variable and soft…

We report the discovery of a relatively bright eclipsing binary system, which consists of a white dwarf and a main sequence K7 star with clear signs of chromospheric and spot activity. The light curve of this system shows $\sim0.2$mag…