Timing observations of RRAT J1819-1458 at Urumqi Observatory

TL;DR

This study presents detailed timing observations of RRAT J1819-1458 at 1.54 GHz, detecting 162 bursts over 94 hours, refining its pulsar parameters, and analyzing burst structures and timing residuals.

Contribution

It provides improved timing parameters and positional accuracy for RRAT J1819-1458 using regular radio observations and burst arrival times.

Findings

Detected 162 bursts with S/N > 5-σ in 94 hours

Refined the pulsar's timing position and parameters

Observed bimodal distribution of timing residuals

Abstract

We report the timing-analysis results obtained for RRAT J1819-1458 from regular timing observations at 1.54 GHz using the Urumqi 25 m radio telescope between 2007 April to 2008 March. RRAT J1819-1458 is a relatively young and highly magnetized neutron star discovered by its sporadic short bursts in the Parkes Multibeam Pulsar Survey data. In 94 hrs of observation data, we detected a total of 162 dispersed bursts of RRAT J1819-1458 with the signal-to-noise ratios (S/Ns) above 5-$\sigma$ threshold. Among them, 5 bursts clearly show two-component structure. The S/N of the strongest burst is 13.3. The source's DM measured through our data is 196.0 $\pm$0.4 pc cm$^{-3}$. The timing position, frequency and its first derivative were determined using standard pulsar timing techniques on the arrival times of these individual bursts. The accuracy of the solved rotating parameters are improved comparing with that in previous publication. Our timing position with 2-$\sigma$ error is consistent with the position of its X-ray counterpart CXOU J181934.1-145804. The effect of timing noise and the phase fluctuation of the individual short bursts on the timing residuals is briefly discussed. The distribution of the timing residuals is bimodal, which cannot be explained readily by timing irregularity.