A Combined Radio Multi-Survey Catalog of Fermi Unassociated Sources

TL;DR

This paper presents a method to identify potential counterparts of unassociated Fermi gamma-ray sources by leveraging existing radio catalogs, especially targeting steep spectrum sources like pulsars, without requiring new observations.

Contribution

It introduces a novel approach using multiple radio catalogs to find associations with unassociated gamma-ray sources, highlighting potential pulsar candidates.

Findings

Identified 591 Fermi unassociated fields with steep-spectrum radio sources.

Found at least 21 sources with pulsar-like gamma-ray properties.

Highlighted additional fields of interest based on radio and gamma-ray data.

Abstract

Approximately one-third of existing $\gamma$-ray sources identified by the $\textit{Fermi Gamma-Ray Space Telescope}$ are considered to be unassociated, with no known counterpart at other frequencies/wavelengths. These sources have been the subject of intense scrutiny and observational effort during the observatory's mission lifetime, and here we present a method of leveraging existing radio catalogs to examine these sources without the need for specific dedicated observations, which can be costly and complex. Via the inclusion of many sensitive low-frequency catalogs we specifically target steep spectrum sources such as pulsars. This work has found steep-spectrum radio sources contained inside 591 $\textit{Fermi}$ unassociated fields, with at least 21 of them being notable for having pulsar-like $\gamma$-ray properties as well. We also identify a number of other fields of interest based on various radio and $\gamma$-ray selections.