Simultaneous Observations of Giant Pulses from Pulsar PSR B0031-07 at 38 MHz and 74 MHz

TL;DR

This study reports simultaneous observations of giant pulses from pulsar PSR B0031-07 at 38 and 74 MHz, revealing their occurrence rate, power-law distribution, and frequency-dependent characteristics over 12 hours.

Contribution

First simultaneous low-frequency observations of giant pulses from PSR B0031-07, analyzing their distribution and frequency dependence with the Long Wavelength Array.

Findings

Giant pulses occur at a rate of about 0.35-0.49% of observed pulses.

Pulse strength distribution follows a power law with indices -4.2 and -4.9.

Most giant pulses are not detected simultaneously across both frequencies.

Abstract

The first station of the Long Wavelength Array (LWA1) was used to study PSR~B0031-07 with simultaneous observations at 38 and 74~MHz. We found that 158 (0.35\%) of the observed pulses at 38~MHz and 221 (0.49\%) of the observed pulses at 74~MHz qualified as giant pulses in a total of 12 hours of observations. Giant pulses are defined as having flux densities of a factor of $\geq$ 90 times that of an average pulse at 38~MHz and $\geq$ 80 times that of an average pulse at 74~MHz. The cumulative distribution of pulse strength follows a power law, with an index of $-$4.2 at 38~MHz and $-$4.9 at 74~MHz. This distribution has a much more gradual slope than would be expected if observing the tail of a Gaussian distribution of normal pulses. The dispersion measure value which resulted in the largest signal-to-noise for dedispersed pulses was DM $=10.9$~pc~cm$^{-3}$. No other transient pulses were detected in the data in the wide dispersion measure range from 1 to 5000~pc~cm$^{-3}$. There were 12 giant pulses detected within the same period from both 38 and 74~MHz, meaning that the majority of them are not generated in a wide band.