Third largest Glitch observed in the rotation of the Crab pulsar
ATel #3777; C. M. Espinoza (JBCA, Manchester, UK), C. Jordan (JBCA, Manchester, UK), C. Bassa (JBCA, Manchester, UK), G. Janssen (JBCA, Manchester, UK), A. G. Lyne (JBCA, Manchester, UK), F. G. Smith (JBCA, Manchester, UK), B. W. Stappers (JBCA, Manchester, UK), P. Weltevrede (JBCA, Manchester, UK)
on 23 Nov 2011; 19:05 UT
Credential Certification: Cristobal Espinoza (cme@jb.man.ac.uk)
Subjects: Radio, Neutron Star, Pulsar
The normal spindown of the Crab pulsar was suddenly interrupted by an increase in its rotation rate at around 12:30 GTM on the 10th of November 2011.
Using the almost daily observations performed by the 42-ft (at 608 MHz) and Lovell (at 1520 MHz) radiotelescopes at Jodrell Bank Observatory, we measure a difference of dNu=1.4 +- 0.1 uHz between the projected spin frequency using pre-glitch ephemerides (http://www.jb.man.ac.uk/pulsar/crab.html) and the current observations.
The glitch occurred between MJD 55875.287 and 55875.899, most likely at MJD 55875.525+-0.005.
We also detect a spindown rate increase dNudot/Nudot ~ 1.6 x10^(-3). More observations in the future will allow a better estimate of this last value.
With a corresponding fractional frequency step dNu/Nu of 49 +- 2 (x10^-9), this is the third largest glitch, out of a total of 25, observed in the rotation of the Crab pulsar during more than 40 years (http://www.jb.man.ac.uk/pulsar/glitches.html).
The two other large glitches had fractional sizes of 81 and 214 (x10^-9) and occurred in August 1989 and March 2003 respectively.
