Timing analysis of rotating radio transients discovered with MeerKAT

Abstract

Pulsars are rapidly rotating neutron stars that emit pulses of radiation at regular intervals, typically ranging from milliseconds to seconds. The precise recording and modelling of the arrival times of pulsar emission is known as timing analysis. Rotating radio transients (RRATs) are a subclass of pulsars that emit pulses very sporadically. Because of the sparse pulse times of arrival (ToAs) typically available for these sources, they are much more difficult to time than regular pulsars, to the extent that few RRATs currently have coherent timing solutions. In this work, we present the results of timing analyses for four RRATs discovered by the MeerTRAP transient survey using MeerKAT. We incorporated additional pulse ToAs from each source that have been detected since their original analysis. We confirmed the known timing solution for PSR J1843$-$0757, with a period of $P=2.03$ seconds, and a period derivative of $\dot{P}=4,13\times10^{-15}$. However, our analysis did not comport with the solution of MTP0005, which we conclude may have been mistakenly identified with the known PSR J1840$-$0815 in the original analysis. Finally, the spin period for MTP0007 was determined to be $1.023(1)$ seconds using a brute-force period fitting approach.