Time-domain and spectral properties of pulsars at 154 MHz

TL;DR

This study uses 154 MHz Murchison Widefield Array observations to analyze pulsar variability and spectral properties, detecting 17 pulsars and observing interstellar scintillation effects in some, revealing insights into their emission and propagation characteristics.

Contribution

First detailed low-frequency variability and spectral analysis of pulsars using MWA, identifying scintillation effects and spectral curvature in specific pulsars.

Findings

Detected 17 pulsars with flux density >0.3 Jy at 154 MHz.

Observed interstellar scintillation in three pulsars over >2 minutes.

Identified spectral curvature in three pulsars.

Abstract

We present 154 MHz Murchison Widefield Array imaging observations and variability information for a sample of pulsars. Over the declination range $-80^{\circ} < {\delta} < 10^{\circ}$ we detect 17 known pulsars with mean flux density greater than 0.3 Jy. We explore the variability properties of this sample on timescales of minutes to years. For three of these pulsars, PSR J0953+0755, PSR J0437-4715 and PSR J0630-2834 we observe interstellar scintillation and variability on timescales of greater than 2 minutes. One further pulsar, PSR J0034-0721, showed significant variability, the physical origins of which are difficult to determine. The dynamic spectra for PSR J0953+0755 and PSR J0437-4715 show discrete time and frequency structure consistent with diffractive interstellar scintillation and we present the scintillation bandwidth and timescales from these observations. The remaining pulsars within our sample were statistically non-variable. We also explore the spectral properties of this sample and find spectral curvature in pulsars PSR J0835-4510, PSR J1752-2806 and PSR J0437-4715.