Compact continuum source-finding for next generation radio surveys

TL;DR

This paper evaluates existing radio source finding tools, identifies their limitations, and introduces a new algorithm, Aegean, that improves completeness and reliability for next-generation radio surveys.

Contribution

The paper provides a comprehensive analysis of current source finders and presents Aegean, a novel algorithm that addresses their shortcomings for large-scale radio surveys.

Findings

Existing tools have high completeness and reliability but fail in ~1% of cases.

Aegean effectively overcomes these failure modes.

Aegean produces more complete and reliable catalogs for future surveys.

Abstract

We present a detailed analysis of four of the most widely used radio source finding packages in radio astronomy, and a program being developed for the Australian Square Kilometer Array Pathfinder (ASKAP) telescope. The four packages; SExtractor, SFind, IMSAD and Selavy are shown to produce source catalogues with high completeness and reliability. In this paper we analyse the small fraction (~1%) of cases in which these packages do not perform well. This small fraction of sources will be of concern for the next generation of radio surveys which will produce many thousands of sources on a daily basis, in particular for blind radio transients surveys. From our analysis we identify the ways in which the underlying source finding algorithms fail. We demonstrate a new source finding algorithm Aegean, based on the application of a Laplacian kernel, which can avoid these problems and can produce complete and reliable source catalogues for the next generation of radio surveys.