Probing Pulsar Scattering between 120 and 280 MHz with the MWA
Abstract
The high sensitivity and wide frequency coverage of the Murchison Widefield Array allow for the measurement of the spectral scaling of the pulsar scattering timescale, α, from a single observation. Here we present three case studies targeted at bright, strongly scattered pulsars J0534+2200 (the Crab pulsar), J0835-4510 (the Vela pulsar), and J0742-2822. We measure the scattering spectral indices to be -3.8 ± 0.2, -4.0 ± 1.5, and -2.5 ± 0.6 for the Crab, Vela, and J0742-2822, respectively. We find that the scattered profiles of both Vela and J0742-2822 are best described by a thin screen model where the Gum Nebula likely contributes most of the observed scattering delay. For the Crab pulsar we see characteristically different pulse shapes compared to higher frequencies, for which none of the scattering screen models we explore are found to be optimal. The presence of a finite inner scale to the turbulence can possibly explain some of the discrepancies.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 2019
- DOI:
- 10.3847/1538-4357/ab0c05
- arXiv:
- arXiv:1903.02087
- Bibcode:
- 2019ApJ...874..179K
- Keywords:
-
- ISM: structure;
- pulsars: general;
- pulsars: individual: PSRs J0534+2200;
- J0742-2822;
- J0835-4510;
- scattering;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Instrumentation and Methods for Astrophysics
- E-Print:
- 14 pages, 8 figures, accepted for publication in ApJ