Related papers: Parameters of X-ray binary system Scorpius X-1
We present ESO-NTT low resolution spectroscopy of the neutron star X-ray transient Cen X-4 in quiescence over a complete orbital cycle. Our data reveal the presence of a K3-7 V companion which contributes 63% to the 5600-6900A flux and…
We observed the low-mass X-ray binary Sco X-1 for 12 nights simultaneously using the Rossi X-Ray Timing Explorer and the Otto Struve Telescope at McDonald Observatory at 1 second time resolution. This is among the most comprehensive…
We report on extensive V, R, and i band photometry of the black-hole candidate Nova Sco 1994 (GRO J1655-40) obtained during March 1996, when the source was close to its quiescent pre-outburst optical brightness (V=17.3). From our…
The observational determination of the lower limit of neutron star masses is crucial for the physics of core-collapse supernovae. In this light, SMC X-1 is an important object because of its estimated pulsar mass lying near or potentially…
We present the results of a long term orbit monitoring program, using sparse aperture masking observations taken with NIRC2 on the Keck-II telescope, of seven G to M-type members of the Upper Scorpius subgroup of the Sco-Cen OB association.…
We have obtained high and intermediate resolution optical spectra of the black-hole candidate Nova Sco 1994 in May/June 1998, when the source was in complete (X-ray) quiescence. We measure the radial velocity curve of the secondary star and…
We accurately determine the fundamental system parameters of the neutron-star X-ray transient Cen X-4 solely using phase-resolved high-resolution UVES spectroscopy. We first determine the radial-velocity curve of the secondary star and then…
The RXTE observations of Scorpius X-1 in 1996-1999 are presented. The properties of its quasi-periodic X-ray oscillations are studied in detail. The results obtained are used for analysis in terms of the transition-layer model (TLM) and the…
Sco X-1 is a low-mass X-ray binary (LMXB) that has one of the most precisely determined set of binary parameters such as the mass accretion rate, companions mass ratio and the orbital period. For this system, as well as for a large fraction…
Neutron stars in low-mass X-ray binaries are considered promising candidate sources of continuous gravitational-waves. These neutron stars are typically rotating many hundreds of times a second. The process of accretion can potentially…
We present optical photometry of XTE J2123-058 during its quiescent state taken in 1999 and 2000. The dominant feature of our R-band light curve is the ellipsoidal modulation of the secondary star, however, in order to fit this…
We present a multi-wavelength study of the low-mass X-ray binary Sco X-1 using Kepler K2 optical data and Fermi GBM and MAXI X-ray data. We recover a clear sinusoidal orbital modulation from the Kepler data. Optical fluxes are distributed…
INTEGRAL IBIS/ISGRI 18-60 keV observations of SS433 performed in 2003-2011 enabled the hard X-ray phase-resolved orbital and precessional light curves and spectra to be constructed. The spectra can be fitted by a power-law with photon index…
Sco X-1 is the brightest persistent X-ray in the sky. It is generally believed that Sco X-1 is a low-mass X-ray binary containing a neutron star accreting from a low-mass donor star where mass transfer is driven by the magnetic braking.…
We report high-resolution optical spectroscopy of the low-mass X-ray binary V395 Car/2S 0921-630 obtained with the MIKE echelle spectrograph on the Magellan-Clay telescope. Our spectra are obtained near superior conjunction of the mass…
We present analysis of extensive monitoring of SS433 by the RXTE observatory collected over the period 1996-2005. The difference between energy spectra taken at different precessional and orbital phases shows the presence of a strong…
We calculate the temperature profiles of (thin) accretion disks around rapidly rotating neutron stars (with low surface magnetic fields), taking into account the full effects of general relativity. We then consider a model for the spectrum…
We present our analysis of the extensive monitoring of SS433 by the RXTE observatory collected over the period 1996-2005. The difference between energy spectra taken at different precessional and orbital phases shows the presence of strong…
The extended hot X-ray emitting gaseous halo of the Milky Way has an optical depth $\sim1$ for the dominant emission lines of \ion{O}{7} and \ion{O}{8}, which are used to infer the halo properties. To improve on halo gas properties, we…
We intended to measure the radial velocity curve of the supergiant companion to the eclipsing high mass X-ray binary pulsar EXO1722-363 and hence determine the stellar masses of the components. We used a set of archival K$_{\rm s}$-band…