X-ray binaries with neutron stars at different accretion stages
Abstract
Different accretion regimes onto magnetized NSs in HMXBs are considered: wind-fed supersonic (Bondi) regime at high accretion rates g s-1, subsonic settling regime at lower and supercritical disc accretion during Roche lobe overflow. In wind-fed stage, NSs in HMXBs reach equilibrium spin periods P * proportional to binary orbital period Pb. At supercritical accretion stage, the system may appear as a pulsating ULX. Population synthesis of Galactic HMXBs using standard assumptions on the binary evolution and NS formation is presented. Comparison of the model P * - Pb (the Corbet diagram), P* - Lx and Pb - Lx distributions with those for the observed HMXBs (including Be X-ray binaries) and pulsating ULXs suggests the importance of the reduction of P* in non-circular orbits, explaining the location of Be X-ray binaries in the model Corbet diagram, and the universal parameters of pulsating ULXs depending only on the NS magnetic fields.
- Publication:
-
High-mass X-ray Binaries: Illuminating the Passage from Massive Binaries to Merging Compact Objects
- Pub Date:
- December 2019
- DOI:
- arXiv:
- arXiv:1811.02842
- Bibcode:
- 2019IAUS..346..219P
- Keywords:
-
- accretion;
- accretion disks;
- binaries: close;
- stars: neutron;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 9 pages, 10 figures, to appear in Proc. IAUS 346