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"Accretion in High Mass X-ray Binaries"
Dr. Manolis Manousakis
University of Geneva, Switzerland

When:  Monday 11 June 2012 at 12:30pm
Where: 2nd Floor Seminar Room

Abstract:
High Mass X-ray Binaries consist of a neutron star or black-hole accreting material from its early-type, massive, stellar companion. The donor star can either be a Be star where accretion is occurred via an accretion disk or a supergiant (sgHMXB) where the compact object orbits close to its companion and accretes directly from its wind. A hidden population of obscured sgHMXBs has been revealed thanks to INTEGRAL. XMM-Newton and INTEGRAL observations of the highly obscured eclipsing sgHMXBs IGR J17252-3616 has shown that the absorbing column density (NH) is highly variable. The variability of NH has been interpreted as the effect of a slow wind with an accretion wake formed around the neutron star. This hypothesis is now supported by hydrodynamical simulations optimized for this system. The mass of the neutron star can be estimated as a by-product of the simulations. In addition, serendipitous observations of a Be/X-ray binary located in the Large Magellanic Cloud, during a giant outburst, allowed us to study and constrain the geometry of the accretion disk.


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