Hunting Gamma-ray emitting FR0 radio galaxies in wide-field sky surveys

TL;DR

This paper identifies seven gamma-ray emitting FR0 radio galaxies using wide-field sky surveys, revealing their spectral similarities to other radio galaxies and suggesting common jet production mechanisms.

Contribution

It reports the first identification of gamma-ray emitting FR0 radio galaxies and analyzes their broadband properties using multi-wavelength survey data.

Findings

Seven gamma-ray emitting FR0 radio galaxies identified.

Gamma-ray properties similar to FR I and II sources.

Detected core-jet structures in gamma-ray bright FR0s.

Abstract

The latest entry in the jetted active galactic nuclei (AGN) family is the Fanaroff-Riley type 0 (FR0) radio galaxies. They share several observational characteristics, e.g., nuclear emission and host galaxy morphology, with FR I sources; however, they lack extended, kiloparsec-scale radio structures, which are the defining features of canonical FR I and II sources. Here we report the identification of 7 gamma-ray emitting AGN as FR0 radio sources by utilizing the high-quality observations delivered by ongoing multi-wavelength wide-field sky surveys, e.g., Very Large Array Sky Survey. The broadband observational properties of these objects are found to be similar to their gamma-ray undetected counterparts. In the gamma-ray band, FR0 radio galaxies exhibit spectral features similar to more common FR I and II radio galaxies, indicating a common gamma-ray production mechanism and the presence of misaligned jets. Although the parsec-scale radio structure of FR0s generally exhibits a wide range, with about half having emission on opposite sides of the core, the gamma-ray detected FR0s tend to have dominant cores with core-jet structures. We conclude that dedicated, high-resolution observations are needed to unravel the origin of relativistic jets in this enigmatic class of faint yet numerous population of compact radio sources.