Giant pulse emission from PSR B0950+08

TL;DR

This study reports the detection of giant pulses from PSR B0950+08 at 103 MHz, revealing high occurrence rates, rapid flux fluctuations, and a power-law intensity distribution, suggesting intrinsic pulsar emission variability.

Contribution

First detection of giant pulses from PSR B0950+08 at low frequency, showing their high occurrence and intrinsic variability, and proposing a link between giant pulses and nulling phenomena.

Findings

Giant pulses follow a power-law intensity distribution with index -2.2.

Occurrence rates of giant pulses vary significantly between days.

Flux densities of pulses fluctuate rapidly and are intrinsic to the pulsar.

Abstract

We present here the detection of giant-pulse emission from PSR B0950+08, a normal-period pulsar. The observations, made at 103 MHz and lasting for about ten months, have shown on a number of days the frequency of occurrence of giant pulses to be the highest among the known pulsars. The flux--density level of successive giant pulses fluctuates rapidly and their occurrence rates within a day's observations as well as between neighboring days show large variations. While on some days PSR B0950+08 shows a large number of giant pulses, there are other days when it shows only "quasi-nulls" with no detectable emission in the power spectrum or in the folded pulse data. The cumulative intensity distribution of these giant pulses appears to follow a power law, with index -2.2. After eliminating instrumental, ionospheric, interplanetary and interstellar diffractive and refractive scintillation effects as the cause, it appears that these intensity variations are intrinsic to the pulsar. We suggest that the giant pulse emission and nulling may be opposite manifestations of the same physical process, in the former case an enhanced number of charges partaking in the coherent radiation process giving rise to an extremely high intensity while in the latter case the coherence could be minimal.