Related papers: An X-Ray Spectroscopic Study of the SMC X-1/Sk 160…
We present a quantitative analysis of the X-ray spectrum of the eclipsing high mass X-ray binary Vela X-1 (4U 0900-40) using archival data from ASCA. The observation covers a time interval centered on eclipse of the X-ray pulsar by the…
We investigate the possibility of obscuring supersoft X-ray sources in the winds of companion stars. We derive limits on the amount of circumstellar material needed to fully obscure a 'canonical' supersoft X-ray source in the Large…
The XMM-Newton survey of the Small Magellanic Cloud (SMC) was performed to study the population of X-ray sources in this neighbouring galaxy. During one of the observations, the symbiotic binary SMC3 was found at its highest X-ray…
Considering the physics of radiation-driven winds of massive stars, the wind properties should depend on the metal content of the stellar atmosphere. Therefore, studying the winds of massive stars in different metallicities provides a…
We present here X-ray spectra of the HMXB SMC X-1 obtained in an observation with the XMM observatory beginning before eclipse and ending near the end of eclipse. With the Reflection Grating Spectrometers (RGS) on board XMM, we observe…
Neutron stars in high-mass X-ray binaries (HMXBs) generally accrete from the wind matter of their massive companion stars. Recently Shakura et al. (2012) suggested a subsonic accretion model for low-luminosity ($<4\times 10^{36}$…
We present high-resolution optical spectroscopy of the X-ray binary system SS433, obtained over a wide range of orbital phases. The spectra display numerous weak absorption features, and include the clearest example seen to date of those…
A review of spectroscopic results obtained from Chandra High Energy Transmission Grating Spectrometer and XMM-Newton Reflection Grating Spectrometer observations of several wind-fed high-mass X-ray binaries (HMXBs) is presented. These…
We have considered the existence of neutron star magnetic field given by the cyclotron lines. We collected the data of 9 sources of high-mass X-ray binaries with supergiant companions as a case of testing our model, to demonstrate their…
High-mass X-ray binary systems are powered by the stellar wind of their donor stars. The X-ray state of Cygnus X-1 is correlated with the properties of the wind which defines the environment of mass accretion. Chandra-HETGS observations…
We continue to study the ultra-luminous X-ray source NGC 7793 P13 in the optical range. In this work, we are testing the model of a spherically symmetric wind atmosphere of the donor star, previously identified as a B9 Ia supergiant. The…
Stellar winds of massive stars are known to be driven by line absorption of UV photons, a mechanism which is prone to instabilities, causing the wind to be clumpy. The clumpy structure hampers wind mass-loss estimates, limiting our…
Mass loss governs the evolution of massive stars and shapes the stellar surroundings. To quantify the impact of the stellar winds we need to know the exact mass-loss rates; however, empirical constraints on the rates are hampered by limited…
We analyze the ASCA spectrum of the Cen X-3 X-ray binary system in eclipse using atomic models appropriate to recombination-dominated level population kinetics in an overionized plasma. In order to estimate the wind characteristics, we…
The distribution of the circumstellar material in systems of supergiant X-ray binaries (SgXBs) is complex and not well probed observationally. We report a detailed study of the spatial distribution of the Fe K{\alpha}-emitting material in…
IGR J18027-2016 is an obscured high-mass X-ray binary formed by a neutron star accreting from the wind of a supergiant companion with a $\sim$4.57 day orbital period. The source shows an asymmetric eclipse profile that remained stable…
Winds of massive stars are suspected to be inhomogeneous (or clumpy), which biases the measures of their mass loss rates. In High Mass X-ray Binaries (HMXBs), the compact object can be used as an orbiting X-ray point source to probe the…
High Mass X-ray Binary Pulsars (HMXBP), in which the companion star is a source of supersonic stellar wind, provide a laboratory to probe the velocity and density profile of such winds. Here, we have measured the variation of the absorption…
The luminous accreting pulsar SMC X-1 is an appropriate target to explore the accretion dynamics. SMC X-1 shows unique quasi-periodic flux variability of 40-65$\,$days known as superorbital modulation. To constrain the accretion structure…
Classical Supergiant X-ray Binaries host a neutron star orbiting a supergiant OB star and display persistent X-ray luminosities of 10$^{35}$ to 10$^{37}$ erg/s. The stellar wind from the massive companion is believed to be the main source…