The physics of accretion in X-ray binary pulsars - relativistic effects, pulse profiles, and emission properties

• Applicant: Professor Dr. Jörn Wilms
• Subject Area: Astrophysics and Astronomy
• Term: from 2014 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 259364563

X-ray pulsars provide an unique opportunity to study the physical mechanisms operating under extreme conditions that are reached in the vicinity of accreting neutron stars, such as temperatures above 1e7 K, magnetic fields above 1e12 G, or the physics of how a plasma that has an initial velocity of ~0.5c is decelerated. Although studies of these objects have already led to a basic understanding of their complex phenomenology, key points such as the size and shape of the emitting region or the physics of interaction between the infalling plasma and the neutron star's magnetic field are still unclear.This application aims at a comprehensive effort to further study and understand the accretion phenomena in X-ray pulsars, especially to answer the questions opened by recent observations of the brightest sources, which cannot be resolved in the frame of the current physical picture of these systems. To achieve this goal, we will mostly concentrate on a sample of bright accreting pulsars which have been or will be observed with the currently operating X-ray missions, to large extent as a result of successful observational proposals by our groups. The application continues the previous successful collaboration of our three research groups at the Institut für Astronomie and Astrophysik (IAAT) of the University of Tübingen, the Erlangen Centre for Astroparticle Physics (ECAP)/Dr. Remeis Sternwarte, Bamberg, of FAU Erlangen-Nürnberg, and the Sternberg Astronomical Institute of the Lomonosov University of Moscow. Our objectives are to develop and improve current theoretical models for the accretion process in strongly magnetized neutron star X-ray binaries and to test these models with new observational methods.

• DFG Programme: Research Grants
• International Connection: Russia
• Partner Organisation: Russian Foundation for Basic Research
• Cooperation Partners: Professor Dr. Konstantin Postnov; Professor Dr. Nikolai Shakura