Accretion in supergiant High Mass X-ray Binaries

Abstract

Supergiant High Mass X-ray Binary systems (sgHMXBs) consist of a massive, late type, star and a neutron star. The massive stars exhibits strong, radiatively driven, stellar winds. Wind accretion onto compact object triggers X-ray emission, which alters the stellar wind significantly. Hydrodynamic simulation has been used to study the neutron star - stellar wind interaction it two sgHMXBs: i) A heavily obscured sgHMXB (IGR J17252-3616) discovered by INTEGRAL. To account for observable quantities (i.e., absorbing column density) we have to assume a very slow wind terminal velocity of about 500 km/s and a rather massive neutron star. If confirmed in other obscured systems, this could provide a completely new stellar wind diagnostics. ii) A classical sgHMXB (Vela X-1) has been studied in depth to understand the origin of the off-states observed in this system. Among many models used to account for this observed behavior (clumpy wind, gating mechanism) we propose that self-organized criticality of the accretion stream is the likely reason for the observed behavior. In conclusion, the neutron star, in these two examples, acts very efficiently as a probe to study stellar winds.

to appear in the Proceedings of "Physics at the Magnetospheric Boundary", Geneve, 25-28 June 2013

References in corpus (5)

• Probing clumpy stellar winds with a neutron star
• Multi-wavelength observations of Galactic hard X-ray sources discovered by INTEGRAL. I. The nature of the companion star
• High variability in Vela X-1: giant flares and off states
• On the nature of `off' states in slowly rotating low-luminosity X-ray pulsars
• Neutron star masses from hydrodynamical effects in obscured sgHMXBs

Cited by in corpus (4)

• The ephemeris, orbital decay, and masses of 10 eclipsing HMXBs
• Formation of wind-captured discs in Supergiant X-ray binaries : consequences for Vela X-1 and Cygnus X-1
• A Clumpy Stellar Wind and Luminosity-Dependent Cyclotron Line Revealed by The First Suzaku Observation of the High-Mass X-ray Binary 4U 1538-522
• High-resolution X-ray spectroscopy of the stellar wind in Vela X-1 during a flare