Properties and observability of glitches and anti-glitches in accreting pulsars

Abstract

Several glitches have been observed in young, isolated radio pulsars, while a clear detection in accretion-powered X-ray pulsars is still lacking. We use the Pizzochero snowplow model for pulsar glitches as well as starquake models to determine for the first time the expected properties of glitches in accreting pulsars and their observability. Since some accreting pulsars show accretion-induced long-term spin-up, we also investigate the possibility that anti-glitches occur in these stars. We find that glitches caused by quakes in a slow accreting neutron star are very rare and their detection extremely unlikely. On the contrary, glitches and anti-glitches caused by a transfer of angular momentum between the superfluid neutron vortices and the non-superfluid component may take place in accreting pulsars more often. We calculate the maximum jump in angular velocity of an anti-glitch and we find that it is expected to be about 1E-5 - 1E-4 rad/s. We also note that since accreting pulsars usually have rotational angular velocities lower than those of isolated glitching pulsars, both glitches and anti-glitches are expected to have long rise and recovery timescales compared to isolated glitching pulsars, with glitches and anti-glitches appearing as a simple step in angular velocity. Among accreting pulsars, we find that GX 1+4 is the best candidate for the detection of glitches with currently operating X-ray instruments and future missions such as the proposed Large Observatory for X-ray Timing (LOFT).

Accepted for publication in Astronomy & Astrophysics. 6 pages. Minor changes to match the final A&A version

References in corpus (7)

• Models of Pulsar Glitches
• Detection of 107 glitches in 36 southern pulsars
• Narrow-band search of continuous gravitational-wave signals from Crab and Vela pulsars in Virgo VSR4 data
• INTEGRAL observations of the variability of OAO 1657-415
• Deformation and crustal rigidity of rotating neutron stars
• Recent Torque Reversal of 4U 1907+09
• Recent activity of the Be/X-ray binary system SAX J2103.5+4545

Cited by in corpus (6)

• Discovery of a Glitch in the Accretion Powered Pulsar SXP 1062
• Discovery of the first anti-glitch event in the rotation-powered pulsar PSR B0540-69
• Continuous gravitational wave emission from neutron stars with pinned superfluids in the core
• Gapless neutron superfluidity can explain the late time cooling of transiently accreting neutron stars
• Continuous gravitational waves from trapped magnetar ejecta and the connection to glitches and antiglitches
• The unusual behaviour of the young X-ray pulsar SXP 1062 during the 2019 outburst