Exploration of Spin-down Rate of Neutron Star in High Mass X-ray Binaries

Abstract

We use the evolutionary population synthesis method to investigate the statistical properties of the wind-fed neutron star (NS) compact ($P_{\mathrm{orb}}<10$ days) high-mass X-ray binaries (HMXBs) in our Galaxy, based on different spin-down models. We find that the spin-down rate in the supersonic propeller phase given \textbf{by assuming that the surrounding material is treated as forming a quasi-static atmosphere} or \textbf{by assuming that the characteristic velocity of matter and the typical Alfv$\acute{e}$n velocity of material in the magnetospheric boundary layer are comparable to the sound speed in the external medium} is too low to produce the observed number of compact HMXBs. We also find that the models suggested \textbf{by assuming that the infalling material is ejected with the corotation velocity at the magnetospheric radius when the magnetospheric radius is larger than the corotation radius} and \textbf{by simple integration of the magnetic torque over the magnetosphere} with a larger spin-down rate than that given by \citet{dav81} or \citet{is75} can predict a reasonable number of observed wind-fed NS compact HMXBs. Our calculated results indicate that subsonic propeller phase may not exist at all by comparing with the observed particular distributions of wind-fed NS compact HMXBs in the $P_s-P_{orb}$ diagram. However, the spin-down rate suggested by \citet{wan85,dai06,jia05} and that given by \citet{dav73} both seem reasonable to produce the observed distribution of wind-fed NS compact HMXBs in the $P_s-P_{orb}$ diagram. We cannot find which spin-down rate seems more reasonable from our calculations.

8 pages, 4 figures, To appear in MNRAS

References in corpus (8)

• Catalogue of high-mass X-ray binaries in the Galaxy ($4^{th}$ edition)
• Unveiling supergiant fast X-ray transient sources with INTEGRAL
• Double-core evolution and the formation of neutron-star binaries with compact companions
• Discovery of slow X-ray pulsations in the high-mass X-ray binary 4U 2206+54
• Neutron star masses from hydrodynamical effects in obscured sgHMXBs
• Exploration of the $\ps-\pb$ Relation for Wind-Fed X-Ray Pulsars
• Testing Models of Magnetic Field Evolution of Neutron Stars with the Statistical Properties of Their Spin Evolutions
• Retrograde wind accretion -- an alternative mechanism for long spin-period of SFXTs

Cited by in corpus (4)

• On the possibility of disk-fed formation in supergiant high-mass X-ray binaries
• Spin evolution of neutron stars in wind-fed high mass X-ray binaries
• Can the Subsonic Accretion Model Explain the Spin Period Distribution of Wind-fed X-ray Pulsars?
• Studies of Cepheus X-4 during 2018 outburst observed with AstroSat