First Detection of $γ$-Ray Emission from the Compact Symmetric Object JVAS J1311+1658

Fuente: arXiv
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Main Authors: Jiang, Xiong, Li, Yang-Ji, Lei, Hai, Wei, Da-Ming
Format: Preprint
Published: 2026
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author Jiang, Xiong
Li, Yang-Ji
Lei, Hai
Wei, Da-Ming
author_facet Jiang, Xiong
Li, Yang-Ji
Lei, Hai
Wei, Da-Ming
contents We report the first detection of $γ$-ray emission from the young radio galaxy JVAS~J1311+1658, classified as a compact symmetric object (CSO). This detection is characterized by a recent GeV $γ$-ray flare identified in Fermi-LAT data during MJD~60032.6--60132.6, with a $γ$-ray source detected at a significance level of $\sim6.2σ$. The average 0.1--300~GeV flux is measured to be $(1.6 \pm 0.6)\times10^{-8}\,\mathrm{ph\,cm^{-2}\,s^{-1}}$, with a photon spectral index of $Γ= 2.15 \pm 0.185$. We find that a radiative model of the radio lobes significantly underestimates the observed $γ$-ray emission. The strong flux and short-term variability over $\sim$100 days suggest that the emission likely originates from newly launched sub-kiloparsec-scale jets at the core. This detection provides a unique window into the extreme environments and early-stage jet activity of young radio galaxies, offering insights into their initial evolution and the formation of relativistic jets in the earliest phases of galaxy growth.
format Preprint
id arxiv_https___arxiv_org_abs_2602_10572
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle First Detection of $γ$-Ray Emission from the Compact Symmetric Object JVAS J1311+1658
Jiang, Xiong
Li, Yang-Ji
Lei, Hai
Wei, Da-Ming
High Energy Astrophysical Phenomena
We report the first detection of $γ$-ray emission from the young radio galaxy JVAS~J1311+1658, classified as a compact symmetric object (CSO). This detection is characterized by a recent GeV $γ$-ray flare identified in Fermi-LAT data during MJD~60032.6--60132.6, with a $γ$-ray source detected at a significance level of $\sim6.2σ$. The average 0.1--300~GeV flux is measured to be $(1.6 \pm 0.6)\times10^{-8}\,\mathrm{ph\,cm^{-2}\,s^{-1}}$, with a photon spectral index of $Γ= 2.15 \pm 0.185$. We find that a radiative model of the radio lobes significantly underestimates the observed $γ$-ray emission. The strong flux and short-term variability over $\sim$100 days suggest that the emission likely originates from newly launched sub-kiloparsec-scale jets at the core. This detection provides a unique window into the extreme environments and early-stage jet activity of young radio galaxies, offering insights into their initial evolution and the formation of relativistic jets in the earliest phases of galaxy growth.
title First Detection of $γ$-Ray Emission from the Compact Symmetric Object JVAS J1311+1658
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2602.10572