Interplanetary Scintillation with the Murchison Widefield Array V: An All-sky Survey of Compact Sources using a Modern Low-frequency Radio Telescope

TL;DR

This paper presents a novel all-sky survey of compact radio sources using Interplanetary Scintillation with the Murchison Widefield Array, demonstrating the method's capabilities and potential for high-resolution low-frequency radio astronomy.

Contribution

It introduces the first large-scale low-frequency IPS survey with the MWA, detailing its methodology, limitations, and potential for future high-resolution studies with SKA-low.

Findings

Survey covers up to half the sky near the ecliptic at 160MHz.

Reasonable results achievable within 30 degrees of the ecliptic.

Potential to probe sub-mJy flux densities at sub-arcsecond resolution.

Abstract

We describe the parameters of a low-frequency all-sky survey of compact radio sources using Interplanetary Scintillation (IPS), undertaken with the Murchison Widefield Array (MWA). While this survey gives important complementary information to low-resolution survey such as the MWA GLEAM survey, providing information on the subarsecond structure of every source, a survey of this kind has not been attempted in the era of low-frequency imaging arrays such as the MWA and LOFAR. Here we set out the capabilities of such a survey, describing the limitations imposed by the heliocentric observing geometry and by the instrument itself. We demonstrate the potential for IPS measurements at any point on the celestial sphere and we show that at 160MHz, reasonable results can be obtained within 30deg of the ecliptic (2{\pi} str: half the sky). We also suggest some observational strategies and describe the first such survey, the MWA Phase I IPS survey. Finally we analyse the potential of the recently-upgraded MWA and discuss the potential of the SKA-low to use IPS to probe sub-mJy flux density levels at sub-arcsecond angular resolution.