Glitch

A glitch is a sudden increase (around 1 part in 10⁶) in the rotational frequency of a pulsar, which usually decreases steadily due to braking provided by the emission of radiation and high-energy particles. It is unknown whether they are related to the timing noise which all pulsars exhibit. Following a glitch is a period of gradual recovery where the observed periodicity slows to a period close to that observed before the glitch. These gradual recovery periods have been observed to last from days to years. Currently, only multiple glitches of the Crab and Vela pulsars have been observed and studied extensively.

Cause

While the exact cause of glitches is unknown, they are thought to be caused by an internal process within the pulsar. This differs from the steady decrease in the star's rotational frequency which is caused by external processes. Although the details of the glitch process are unknown, it is thought that the resulting increase in the pulsar's rotational frequency is caused by a brief coupling of the pulsar's faster-spinning superfluid core to the crust, which are usually decoupled. This brief coupling transfers angular momentum from core to the surface, which causes a decrease in the measured period.^[1]

Implications

Assuming that the mechanism described above is correct, observed pulsar glitches set a limit on the moment of inertia of the pulsar being observed and, thus, the mass-radius relation possible in dense nuclear matter. More generally, observations of pulsar glitches allow to extract indirect information on the dense nuclear matter in neutron star interiors, in particular its superfluid properties.^[1]

References

↑ ^1.0 ^1.1 Antonelli, Marco; Montoli, Alessandro; Pizzochero, Pierre (November 2022), "Insights into the Physics of Neutron Star Interiors from Pulsar Glitches", Astrophysics in the XXI Century with Compact Stars, pp. 219–281, doi:10.1142/9789811220944_0007, ISBN 978-981-12-2093-7

Link, Bennett; Epstein, Richard I.; Van Riper, Kenneth A. (1992). "Pulsar glitches as probes of neutron star interiors". Nature 359 (6396): 616–618. doi:10.1038/359616a0. Bibcode: 1992Natur.359..616L.
https://web.archive.org/web/20051018233130/http://www.saao.ac.za/~wgssa/as4/urama.html http://www.saao.ac.za/~wgssa/as4/urama.html
Rowan, L. (2000). "ASTRONOMY: Pulsar Glitches". Science 289 (5476): 13c–13. doi:10.1126/science.289.5476.13c.

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[:0-1] 1.0 ^1.1 Antonelli, Marco; Montoli, Alessandro; Pizzochero, Pierre (November 2022), "Insights into the Physics of Neutron Star Interiors from Pulsar Glitches", Astrophysics in the XXI Century with Compact Stars, pp. 219–281, doi:10.1142/9789811220944_0007, ISBN 978-981-12-2093-7

v t e Neutron star
Types	Radio-quiet Pulsar
Single pulsars	Magnetar Soft gamma repeater Anomalous X-ray Rotating radio transient
Binary pulsars	Binary X-ray pulsar X-ray binary X-ray burster List Millisecond Be/X-ray Spin-up
Properties	Blitzar Fast radio burst Bondi accretion Chandrasekhar limit Gamma-ray burst Glitch Neutronium Neutron-star oscillation Optical Pulsar kick Quasi-periodic oscillation Relativistic Rp-process Starquake Timing noise Tolman–Oppenheimer–Volkoff limit Urca process
Related	Gamma-ray burst progenitors Astroseismology Compact star Quark star Exotic star Supernova Supernova remnant Related links Hypernova Kilonova Neutron star merger Quark-nova White dwarf Related links Stellar black hole Related links Radio star Pulsar planet Pulsar wind nebula Thorne–Żytkow object
Discovery	LGM-1 Centaurus X-3 Timeline of white dwarfs, neutron stars, and supernovae
Satellite investigation	Rossi X-ray Timing Explorer Fermi Gamma-ray Space Telescope Compton Gamma Ray Observatory Chandra X-ray Observatory
Other	X-ray pulsar-based navigation Tempo software program Astropulse The Magnificent Seven

Glitch

Contents

Cause

Implications

See also

References