Can the Subsonic Accretion Model Explain the Spin Period Distribution of Wind-fed X-ray Pulsars?

Abstract

Neutron stars in high-mass X-ray binaries (HMXBs) generally accrete from the wind matter of their massive companion stars. Recently Shakura et al. (2012) suggested a subsonic accretion model for low-luminosity ($<4\times 10^{36}$ ergs${}^{-1}$), wind-fed X-ray pulsars. To test the feasibility of this model, we investigate the spin period distribution of wind-fed X-ray pulsars with a supergiant companion star, using a population synthesis method. We find that the modeled distribution of supergiant HMXBs in the spin period - orbital period diagram is consistent with observations provided that the winds from the donor stars have relatively low terminal velocities ($\lesssim 1000$ kms${}^{-1}$). The measured wind velocities in several supergiant HMXBs seem to favor this viewpoint. The predicted number ratio of wind-fed X-ray pulsars with persistent X-ray luminosities higher and lower than $4\times 10^{36}$ ergs${}^{-1}$ is about $1:10$.

17 pages, 3 figures, accepted for publication in ApJ

References in corpus (19)

• Mass loss from late-type WN stars and its Z-dependence: very massive stars approaching the Eddington limit
• "Propeller" Regime of Disk Accretion to Rapidly Rotating Stars
• On the consistent treatment of the quasi-hydrostatic layers in hot star atmospheres
• On the formation of Be stars through binary interaction
• Populating the Galaxy with low-mass X-ray binaries
• VLT/UVES spectroscopy of Wray 977, the hypergiant companion to the X-ray pulsar GX301-2
• Origin of Two Types of X-Ray Outbursts in Be/X-Ray Binaries. I. Accretion Scenarios
• Bright Flares in Supergiant Fast X-ray Transients
• Measuring the stellar wind parameters in IGR J17544-2619 and Vela X-1 constrains the accretion physics in Supergiant Fast X-ray Transient and classical Supergiant X-ray Binaries
• The origin of long-period X-ray pulsars
• SXP 1062: an Evolved Magnetar in a BeXB ?
• Is the flip-flop behaviour of accretion shock cones on to black holes an effect of coordinates?
• On the Spin Period Distribution in Be/X-ray Binaries
• Revisiting the Flip-Flop Instability of Hoyle-Lyttleton Accretion
• Spin-up/spin-down of neutron star in Be-X-ray binary system GX 304-1
• Exploration of the $\ps-\pb$ Relation for Wind-Fed X-Ray Pulsars
• The donor star of the X-ray pulsar X1908+075
• Expected number of supergiant fast X-ray transients in the Milky Way
• Exploration of Spin-down Rate of Neutron Star in High Mass X-ray Binaries

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