Spin-down and emission variations for PSR J0742−2822

Abstract

Abstract PSR J0742−2822 is known for its quasi-periodic changes in the observed pulse profile and spindown rate. In this paper, we analyzed 13 years of timing data obtained with the Nanshan 25-m radio telescope and the Parkes 64-m radio telescope. We found that the average values of the spin-down rate ( 〈 ν ˙ 〉 ) of this pulsar changed in four different states. We investigated the correlation between ν ˙ and W 50, and ascertained that the correlation changed in different 〈 ν ˙ 〉 states. Moreover, not all the changes in 〈 ν ˙ 〉 states and correlation can be associated with glitch activities. We examined the long term evolution of γ-ray flux (0.1–300 GeV) and the pulse profiles corresponding to the four different states using Fermi-LAT Pass 8 (P8R3) data from 2008 August 5 to 2019 October 1. We did not detect a significant change in γ-ray flux or the pulse profile. Our results suggest that the connection between pulsar rotation and emission is more complex than previously reported for this pulsar.