On the pulsar spin frequency derivatives and the glitch activity

Abstract

The number of sudden spin-ups in radio pulsars known as pulsar glitches has increased over the years. Though a consensus has not been reached with regards to the actual cause of the phenomenon, the electromagnetic braking torque on the crust quantified via the magnitude of pulsar spin frequency first derivative, $\dot{\nu }$ is a key factor in mechanisms put across toward the understanding of the underlying principles involved. The glitch size has been used to establish a quantity used to constrain the mean possible change in pulsar spin frequency $(\nu )$ per year due to a glitch known as the `glitch activity'. Traditionally, the glitch activity parameter $A_g$ is calculated from the cumulative glitch sizes in a pulsar at a certain observational time span. In this analysis, we test the possibility of of quantifying the $A_g$ with the pulsars main spin frequency derivatives (i.e. $\dot{\nu }$ and $\ddot{\nu }$). In this approach, the ratio of the frequency derivatives, i.e. $|\ddot{\nu }|/{\dot{\nu }}^2$ is seen to constrains the glitch activity in radio pulsars. The glitch size is found to be independent of the magnitude of the ratio, however, based on the recorded glitch events, the lower end of $|\ddot{\nu }|/{\dot{\nu }}^2$ distribution appear to have more glitches. The minimum inter-glitch time interval in the ensemble of pulsars scale with the ratio as $t_g\sim 3.35(|\ddot{\nu }|/{\dot{\nu }}^2{)}^{0.23}$. The $A_g$ quantified in this analysis supports the idea of neutron star inner-crust superfluid being the reservoir of momentum transferred during glitches. It suggests that the moment of inertia of the inner-crust to be at most 10 % of the entire neutron star moment of inertia.

arXiv commentThis article is to be published in Astrophysics and Space Science (12 pages, 6 figures and 3 tables)

References in corpus (38)

• Magnetars
• A study of 315 glitches in the rotation of 102 pulsars
• Pulsar Constraints on Neutron Star Structure and Equation of State
• Models of Pulsar Glitches
• An analysis of the timing irregularities for 366 pulsars
• 45 Years of Rotation of the Crab Pulsar
• Pulsar glitches: The crust is not enough
• The Parkes multibeam pulsar survey: III. Young pulsars & the discovery and timing of 200 pulsars
• Neutron conduction in the inner crust of a neutron star in the framework of the band theory of solids
• Detection of 107 glitches in 36 southern pulsars
• Crustal Entrainment and Pulsar Glitches
• The glitch-induced identity changes of PSR J1119-6127
• Development of a pulsar-based timescale
• Using Neutron Star Observations to Determine Crust Thicknesses, Moments of Inertia, and Tidal Deformabilities
• High time resolution observations of the January 2000 glitch in the Vela pulsar
• 16 Years of RXTE Monitoring of Five Anomalous X-ray Pulsars
• PSR J2229+6114: Discovery of an Energetic Young Pulsar in the Error Box of the EGRET Source 3EG J2227+6122
• Glitches in Southern Pulsars
• The glitch activity of neutron stars
• Quaking Neutron Stars
• Pinning down the superfluid and measuring masses using pulsar glitches
• Vortex pinning and dynamics in the neutron star crust
• The largest glitch observed in the Crab pulsar
• The UTMOST pulsar timing programme I: overview and first results
• X-ray and Radio Timing of the Pulsar in 3C 58
• Two types of glitches in a solid quark star model
• Pulsed Gamma-rays from PSR J2021+3651 with the Fermi Large Area Telescope
• A strong $\ddot{\nu }-\dot{\nu }$ correlation in radio pulsars with implications for torque variations
• Pressure of Degenerate and Relativistic electrons in a superhigh magnetic field
• Glitch time series and size distributions in eight prolific pulsars
• Size-waiting-time correlations in pulsar glitches
• Monotonic and cyclic components of radio pulsars spin-down
• Revisiting neutron starquakes caused by spin-down
• How massive are the superfluid cores in the Crab and Vela pulsars and why their glitch-events are accompanied with under and overshootings?
• Glitching pulsars: unraveling the interactions of general relativity with quantum fields in the strong field regimes
• On the second derivatives of periods and braking indices in radio pulsars
• Statistical estimates of the pulsar glitch activity
• Microglitches in radio pulsars: the role of strange nuggets