Radio Counterpart Candidates to Unassociated 4FGL-DR2 Sources

• Published in: The Astrophysical journal 2021-06, Vol.914 (1), p.42
• Main Authors: Bruzewski, S., Schinzel, F. K., Taylor, G. B., Petrov, L.
• Format: Article
• Language: English
• Subjects: Active galactic nuclei; Active galaxies; Astrophysics; Celestial bodies; Gamma ray astronomy; Gamma rays; High energy astrophysics; Pulsars; Radio astronomy; Radio continuum emission; Radio frequency; Radio source catalogs; Radio sources (astronomy); Sky surveys (astronomy); Space telescopes; Spectral index; Surveys
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/abf73b

For the duration of the Fermi Gamma-Ray Space Telescope's mission, approximately one-third of the point sources detected have been noted as “unassociated,” meaning that they seem to have no known counterpart at any other wavelength/frequency. This mysterious part of the gamma-ray sky is perhaps one of the largest unknowns in current astronomical pursuits and as such has been probed extensively by various techniques at various frequencies. Radio frequencies have been perhaps one of the most fruitful, producing a large fraction of the identified and associated active galactic nuclei and pulsars noted in each update of the point-source catalogs. Here we present a catalog of 7432 radio counterpart candidates for unassociated gamma-ray fields in the Second Data Release of the Fourth Fermi Point Source Catalog (4FGL-DR2). A description of the catalog and source types is provided followed by a discussion that demonstrates how the results of this work will aid new associations and identifications. As part of this work, we also present a first catalog derived from “quicklook” images of the Very Large Array Sky Survey.