Dual-frequency single-pulse study of PSR B0950+08

TL;DR

This study compares single-pulse emissions of PSR B0950+08 at two frequencies, revealing their similarity to ordinary pulses, and discusses interstellar medium effects and spectral structures that could inform understanding of Fast Radio Bursts.

Contribution

It provides a dual-frequency analysis of PSR B0950+08's single pulses, highlighting the role of interstellar scintillation and spectral features in pulse variability and FRB-like phenomena.

Findings

Single pulses resemble ordinary pulsar emissions more than giant pulses.

Interstellar scintillation significantly influences pulse fluence variability.

Spectral structures akin to FRB 'sad trombones' are observed, explained by radius-to-frequency mapping.

Abstract

PSR B0950+08 is a bright non-recycled pulsar whose single-pulse fluence variability is reportedly large. Based on observations at two widely separated frequencies, 55 MHz (NenuFAR) and 1.4 GHz (Westerbork Synthesis Radio Telescope), we review the properties of these single pulses. We conclude that they are more similar to ordinary pulses of radio emission than to a special kind of short and bright Giant Pulses, observed from only a handful of pulsars. We argue that temporal variation of properties of interstellar medium along the line of sight to this nearby pulsar, namely the fluctuating size of decorrelation bandwidth of diffractive scintillation makes important contribution to observed single-pulse fluence variability. We further present interesting structures in the low-frequency single-pulse spectra that resemble the "sad trombones" seen in Fast Radio Bursts (FRBs); although for PSR B0950+08 the upward frequency drift is also routinely present. We explain these spectral features with radius-to-frequency mapping, similar to the model developed by Wang et al. (2019) for FRBs. Finally, we speculate that microsecond-scale fluence variability of the general pulsar population remains poorly known, and that its further study may bring important clues about the nature of FRBs.