A New Sample of Gamma-Ray Emitting Jetted Active Galactic Nuclei

TL;DR

This study compiles a large sample of gamma-ray emitting jetted AGN from the Fermi LAT catalog, analyzing their optical spectra to refine classifications and measure redshifts, revealing diverse AGN types and changing-look phenomena.

Contribution

It provides a comprehensive, updated catalog of gamma-ray jetted AGN with refined classifications and redshifts, including identification of changing-look AGN and ambiguous sources.

Findings

2980 gamma-ray sources identified as jetted AGN

40% are BL Lac objects, 23% flat-spectrum radio quasars

1.1% are changing-look AGN

Abstract

We considered the fourth catalog of gamma-ray point sources produced by the Fermi Large Area Telescope (LAT) and selected only jetted active galactic nuclei (AGN) or sources with no specific classification, but with a low-frequency counterpart. Our final list is composed of 2980 gamma-ray point sources. We then searched for optical spectra in all the available literature and publicly available databases, to measure redshifts and to confirm or change the original LAT classification. Our final list of gamma-ray emitting jetted AGN is composed of BL Lac Objects (40%), flat-spectrum radio quasars (23%), misaligned AGN (2.8%), narrow-line Seyfert 1, Seyfert, and low-ionization nuclear emission-line region galaxies (1.9%). We also found a significant number of objects changing from one type to another, and vice versa (changing-look AGN, 1.1%). About 30% of gamma-ray sources still have an ambiguous classification or lack one altogether.