Related papers: Stellar wind parameters of massive stars in accret…
In high mass X-ray binaries (HMXBs), an accreting compact object orbits a high mass star which loses mass through a dense and inhomogeneous wind. Using the compact object as an X-ray backlight, the time variability of the absorbing column…
Neutron star high-mass X-ray binaries are well-studied in wavebands between the infrared and hard X-rays. Their low-frequency millimeter and radio properties, on the other hand, remain poorly understood. We present observations of the…
Vela X-1 is the archetype of high-mass X-ray binaries, composed of a neutron star and a massive B supergiant. The supergiant is a source of a strong radiatively-driven stellar wind. The neutron star sweeps up this wind, and creates a huge…
Nearly all types of massive stars with radiatively driven stellar winds are X-ray sources that can be observed by the presently operating powerful X-ray telescopes. In this review I briefly address recent advances in our understanding of…
INTEGRAL tripled the number of super-giant high-mass X-ray binaries (sgHMXB) known in the Galaxy by revealing absorbed and fast transient (SFXT) systems. Quantitative constraints on the wind clumping of massive stars can be obtained from…
We study the evolution of a low mass x-ray binary coupling a binary stellar evolution code with a general relativistic code that describes the behavior of the neutron star. We assume the neutron star to be low--magnetized (B~10^8 G). In the…
We run numerical simulations to study high-power wind accretion in a massive binary system during a high mass loss event. The system consists of an evolved primary star with a zero age main sequence mass of $ M_{1} = \rm 100~M_{\odot}$ and…
We have observed the persistent but optically unidentified X-ray source X1908+075 with the PCA and HEXTE instruments on RXTE. The binary nature of this source was established by Wen, Remillard, & Bradt (2000) who found a 4.4-day orbital…
Massive X-ray binaries are usually classified depending on the properties of the donor star in classical, supergiant and Be X-ray binaries. The massive X-ray binary 4U 2206+54 does not fit in any of these groups, and deserves a detailed…
X-Ray bursts (XRBs) are powerful thermonuclear events on the surface of accreting neutron stars (NSs), which can synthesize intermediate-mass elements. Although the high surface gravity prevents an explosive ejection, a small fraction of…
Extreme helium stars are very rare low-mass supergiants in a late stage of evolution. They are probably contracting to become white dwarfs following a violent phase of evolution which caused them to become hydrogen-deficient giants,…
We describe here the nature, formation and evolution of the supergiant high mass X-ray binary (HMXB) population, i.e. systems accreting the stellar wind of supergiant stars. There are now many new observations, from the high-energy side…
Aims: We study the acceleration of the stellar winds of rapidly rotating low mass stars and the transition between the slow magnetic rotator and fast magnetic rotator regimes. We aim to understand the properties of stellar winds in the fast…
High-mass X-ray binaries (HMXBs) represent an important phase in the evolution of massive binary systems. HMXBs provide unique diagnostics to test massive-star evolution, to probe the physics of radiation-driven winds, to study the process…
We explore the possibility that neutron stars accreting from the winds of main-sequence stellar companions account for a significant fraction of low-luminosity, hard X-ray sources (L_X <~ 10^35 ergs/s; 1-10 keV) in the Galaxy. This work was…
In the magneto-centrifugal mechanism for jet formation, accreting neutron stars are assumed to produce relativistic jets only if their surface magnetic field is weak enough ($B \sim 10^8$ G). However, the most common manifestation of…
A substantial fraction of the known neutron stars resides in X-ray binaries -- systems in which one compact object accretes matter from a companion star. Neutron stars in X-ray binaries have magnetic fields among the highest found in the…
In this chapter we give an overview of the properties of X-ray binary systems containing a weakly magnetized neutron star. These are old (Giga-years life-time) semi-detached binary systems containing a neutron star with a relatively weak…
The appearance of subsonic propellers situated in a strong wind is discussed. We show that it is similar to the appearance of anomalous X-ray pulsars (AXPs) provided the mass and the magnetic moment of neutron stars are 1.4 solar masses,…
We calculate the X-ray emission from both constant and time evolving shocked fast winds blown by the central stars of planetary nebulae (PNs) and compare with observations. Using spherically symmetric numerical simulations with radiative…