Accretion in the spin-down regime


Ekşi K. Y. , KUTLU E.

Conference on Astrophysics of Neutron Stars in Honor of M Ali Alpar (ASTRONS), Cesme, Türkiye, 2 - 06 Ağustos 2010, cilt.1379 identifier identifier

  • Cilt numarası: 1379
  • Doi Numarası: 10.1063/1.3629505
  • Basıldığı Şehir: Cesme
  • Basıldığı Ülke: Türkiye

Özet

Accretion driven millisecond X-ray pulsars can accrete over a wide range of mass flow rates. The pulsations persist even at small accretion rates at which these objects would be expected to be in the propeller stage. We argue that the inner regions of disks around millisecond X-ray pulsars are sufficiently thick that a fraction of the inflowing matter can accrete even in the spin-down regime from regions of the disk away from the disk plane. This allows these systems to be bright throughout a wide range of mass flow rates. We model the lightcurve of SAX J1808.4-3658 during an outburst and showthat the rapid decay stage can be modeled with fractional accretion in the spin-down regime.