A detailed study of giant pulses from PSR B1937+21 using the Large European Array for Pulsars

J W Mckee,L Wang,B W Stappers,M Gaikwad,K J Lee,C G Bassa,G H Janssen,K Liu,R Karuppusamy,I Cognard,M Kramer,D Perrodin,S A Sanidas,R Smits,S Chen,W W Zhu

doi:10.1093/mnras/sty3058

Abstract

We have studied 4265 giant pulses (GPs) from the millisecond pulsar B1937+21; the largest-ever sample gathered for this pulsar, in observations made with the Large European Array for Pulsars. The pulse energy distribution of GPs associated with the interpulse are well-described by a power law, with index $\alpha = -3.99 \pm 0.04$, while those associated with the main pulse are best-described by a broken power law, with the break occurring at $\sim7$ Jy $\mu$s, with power law indices $\alpha_{\text{low}} = -3.48 \pm 0.04$ and $\alpha_{\text{high}} = -2.10 \pm 0.09$. The modulation indices of the GP emission are measured, which are found to vary by $\sim0.5$ at pulse phases close to the centre of the GP phase distributions. We find the frequency-resolved structure of GPs to vary significantly, and in a manner that cannot be attributed to the interstellar medium influence on the observed pulses. We examine the distribution of polarisation fractions of the GPs and find no correlation between GP emission phase and fractional polarisation. We use the GPs to time PSR B1937+21 and although the achievable time of arrival precision of the GPs is approximately a factor of two greater than that of the average pulse profile, there is a negligible difference in the precision of the overall timing solution when using the GPs.

Highlights

PSR B1937+21 (PSR J1939+2134) was the first millisecond pulsar (MSP) to be discovered (Backer et al 1982), and with a period of1.56 ms, was the fastest-spinning known pulsar, until the discovery of the 1.40 ms PSR J1748−2446ad (Hessels et al 2006)
giant pulses (GPs), which is the largest sample of GPs ever gathered for PSR B1937+21
As expected following Kinkhabwala & Thorsett (2000), the GP emission was found to occur in narrow phase windows located at the trailing edges of the regular emission regions, with the MGP trailing the main pulse (MP) peak by

Summary

Introduction

PSR B1937+21 (PSR J1939+2134) was the first millisecond pulsar (MSP) to be discovered (Backer et al 1982), and with a period of1.56 ms, was the fastest-spinning known pulsar, until the discovery of the 1.40 ms PSR J1748−2446ad (Hessels et al 2006). Campbell 1970, Staelin & Sutton 1970), PSR B1937+21 was the second pulsar found to exhibit so-called ‘giant pulse’ (GP) emission (Wolszczan et al 1984, Cognard et al 1996); occasional very shortduration single pulses with flux densities greatly exceeding that ?. (i) The pulse width of individual GPs is typically much narrower than that of regular single pulses, with (unresolved) durations as short as 2 ns, in the case of the Crab Pulsar (Hankins et al 2003). (ii) The pulse energy distributions of the regular emission are usually well-modelled as a log-normal distribution, while pulse energies of GPs are found to follow a power law distribution

Results

Discussion

Conclusion