The gamma-ray emission from young radio galaxies and quasars

TL;DR

This study analyzes over 11 years of Fermi-LAT data to investigate gamma-ray emission from the largest sample of young radio galaxies and quasars, revealing insights into their energetic processes and jet structures.

Contribution

It provides the first comprehensive gamma-ray analysis of 162 young radio sources, including individual and stacked data, advancing understanding of their high-energy emission.

Findings

Detected gamma-ray emission in some sources

Set upper limits for undetected sources

Discussed implications for gamma-ray emission models

Abstract

According to radiative models, radio galaxies are predicted to produce gamma-rays from the earliest stages of their evolution onwards. The study of the high-energy emission from young radio sources is crucial for providing information on the most energetic processes associated with these sources, the actual region responsible for this emission, as well as the structure of the newly born radio jets. Despite systematic searches for young radio sources at gamma-ray energies, only a handful of detections have been reported so far. Taking advantage of more than 11 years of Fermi-LAT data, we investigate the gamma-ray emission of 162 young radio sources (103 galaxies and 59 quasars), the largest sample of young radio sources used so far for a gamma-ray study. We analysed the Fermi-LAT data of each source separately to search for a significant detection. In addition, we performed the first stacking analysis of this class of sources in order to investigate the gamma-ray emission of the young radio sources that are undetected at high energies. In this note we present the results of our study and we discuss their implications for the predictions of gamma-ray emission from this class of sources.