As pulsars lose energy, primarily in the form of magnetic dipole radiation, their rotation slows down accordingly. For some pulsars, this spin-down is interrupted by occasional abrupt spin-up events known as glitches¹. A glitch is hypothesized to be a catastrophic release of pinned vorticity² that provides an exchange of angular momentum between the superfluid outer core and the crust. This is manifested by a minute alteration in the rotation rate of the neutron star and its co-rotating magnetosphere, which is revealed by an abrupt change in the timing of observed radio pulses. Measurement of the flux density, polarization and single-pulse arrival times of the glitch with high time resolution may reveal the equation of state of the crustal superfluid, its drag-to-lift ratio and the parameters that describe its friction with the crust³. This has not hitherto been possible because glitch events happen unpredictably. Here we report single-pulse radio observations of a glitch in the Vela pulsar, which has a rotation frequency of 11.2 hertz. The glitch was detected on 2016 December 12 at 11:36 universal time, during continuous observations of the pulsar over a period of three years. We detected sudden changes in the pulse shape coincident with the glitch event: one pulse was unusually broad, the next pulse was missing (a ‘null’) and the following two pulses had unexpectedly low linear polarization. This sequence was followed by a 2.6-second interval during which pulses arrived later than usual, indicating that the glitch affects the magnetosphere.

Item Type:	Refereed Article
Keywords:	pulsars
Research Division:	Physical Sciences
Research Group:	Astronomical sciences
Research Field:	Galactic astronomy
Objective Division:	Expanding Knowledge
Objective Group:	Expanding knowledge
Objective Field:	Expanding knowledge in the physical sciences
UTAS Author:	Palfreyman, J (Dr Jim Palfreyman)
UTAS Author:	Dickey, JM (Professor John Dickey)
UTAS Author:	Ellingsen, S (Professor Simon Ellingsen)
ID Code:	125568
Year Published:	2018
Web of Science® Times Cited:	70
Deposited By:	Mathematics and Physics
Deposited On:	2018-04-23
Last Modified:	2019-02-27
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