Related papers: An ultracompact X-ray binary in the globular clust…

We report the discovery of the binary millisecond pulsar J0514-4002A, which is the first known pulsar in the globular cluster NGC 1851 and the first pulsar discovered using the Giant Metrewave Radio Telescope (GMRT). The pulsar has a…

A search for spectroscopic binaries on the main sequence of the nearby globular cluster M4 has been undertaken with Argus, the multi-object spectrograph on the CTIO 4.0m telescope. A pair of radial velocities (median precision $\simeq$ 2…

Black hole (BH) ultracompact X-ray binaries (UCXBs) are potential Galactic low-frequency gravitational wave (GW) sources. As an alternative channel, BH UCXBs can evolve from BH+He star binaries. In this work, we perform a detailed stellar…

We study the formation of neon-enriched donor stars in ultracompact X-ray binaries (orbital periods P<80 min) and show that their progenitors have to be low-mass (0.3 - 0.4 solar mass) ``hybrid'' white dwarfs (with CO cores and thick helium…

X-ray burst oscillations are quasi-coherent periodic signals at frequencies close to the neutron star spin frequency. They are observed during thermonuclear Type I X-ray bursts from a number of low-mass X-ray binaries (LMXBs) hosting a…

We report the first results of the Chandra temporal monitoring of the ultra-luminous X-ray sources (ULXs) in the Antennae galaxies (NGC 4038/39). Observations at four different epochs, covering time scales of 2 years to 2 months, show…

There exists a group of persistently faint galactic X-ray sources that, based on their location in the galaxy, high L_x/L_opt, association with X-ray bursts, and absence of low frequency X-ray pulsations, are thought to be low-mass X-ray…

In the mHz gravitational-wave band, galactic ultra-compact binaries (UCBs) are continuous sources emitting at near-constant frequency. The signals from many of these galactic binaries will be sufficiently strong to be detectable by the…

We report here results from detailed timing and spectral studies of the high mass X-ray binary pulsar 4U~1538--52 over several binary periods using observations made with the Rossi X-ray Timing Explorer (RXTE) and BeppoSAX satellites. Pulse…

We have obtained Hubble Space Telescope/STIS low-resolution ultraviolet spectra of the X-ray pulsar 4U 1626-67 (=KZ TrA); 4U 1626-67 is unusual even among X-ray pulsars due to its ultra-short binary period (P=41.4 min) and remarkably low…

Context. Ultracompact X-ray binaries (UCXBs) typically consist of a white dwarf donor and a neutron star or black hole accretor. The evolution of UCXBs and very low mass ratio binaries in general is poorly understood. Aims. We investigate…

We find convincing observational evidence to confirm the optical identification of the X-ray burster X1746-370 located in the globular cluster NGC6441. Chandra/HRC-I imaging yields a much improved X-ray position for the source, which we…

We investigate the nature of CXOU J005440.5-374320 (J0054), a peculiar bright ($\sim$$4\times10^{39}$ erg/s) and soft X-ray transient in the spiral galaxy NGC 300 with a 6-hour periodic flux modulation that was detected in a 2014 Chandra…

We report on multi-band observations of the transient source Swift J0840.7-3516, which was detected in outburst in 2020 February by the Neil Gehrels Swift Observatory. The outburst episode lasted just ~5 days, during which the X-ray…

We present the first results of the observations of the X-ray pulsars LMC X-4, 4U0352+309 and EXO1722-363 performed with the INTEGRAL observatory. The LMC X-4 was investigated during the whole superorbital cycle ($\sim$30 days) and it was…

Photometric analysis of $BVR_C$ light curves of newly discovered eclipsing binary GSC 0008-00901 is presented. The orbital period is improved to 0.28948(11) days. Photometric parameters are determined, as well. The analysis yielded to…

We discovered 2.8 s pulsations in the X-ray emission of the ultraluminous X-ray source (ULX) M51 ULX-7 within the UNSEeN project, which was designed to hunt for new pulsating ULXs (PULXs) with XMM-Newton. The pulse shape is sinusoidal and…

The strange timing property of X-ray pulsar 1E 1207.4-5209 can be explained by the hypothesis that it is a member of an ultra-compact binary system. This paper confronts the ultra-compact assumption with the observed properties of this…

We present an X-ray timing analysis of the transient X-ray binary MXB 1658-298, using data obtained from the RXTE and XMM-Newton observatories. We have made 27 new mid eclipse time measurements from observations made during the two…

We present the results from coordinated X-ray observations of the ultraluminous X-ray source NGC 5204 X-1 performed by NuSTAR and XMM-Newton in early 2013. These observations provide the first detection of NGC 5204 X-1 above 10 keV,…