A connection between radio state changing and glitch activity in PSR J0742-2822

PSR J0742-2822 exhibits two distinct emission states that are identified by discrete changes in the observed pulse profile. these changes have previously been shown to correlate with changes in the derivative of the pulse frequency. in this paper, we use observations with the parkes radio telescope at a centre frequency of 1369 and 3100 MHz to produce high phase resolution polarization profiles for the twomodes and perform a detailed study of the correlation between observed pulse shape and spin-down rate. we find no correlation for at least 200 d prior to a glitch in the pulsar at MJD 550 22, following which the correlation becomes strong. this suggests a link between the emission state switching phenomenon and glitch events. we discuss the possibility that emission state switching is driven by the interaction between the magnetosphere and the interior of the neutron star. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.