We report the detection (> 5sigma ) with Fermi-LAT of gamma-ray emission from the nearby (z = 0.014) radio galaxy, PKS 1718-649. This is the first detection in gamma-rays of a bona fide Compact Symmetric Object, a class of sources that are thought to represent the first stage in the evolution of extragalactic radio sources. A detection in the gamma-ray band is a clear indication of a non-thermal high-energy component and provides us with important insights on the physical conditions of expanding young radio sources. The symmetric radio morphology indicates that the source is seen at a large inclination angle and disfavors a contribution of the jet boosted emission. The steep gamma-ray spectrum and steady faint emission are consistent with the scenario of isotropic gamma-ray emission from the compact (<2pc) radio lobes, as proposed by models of expanding young radio sources. We discuss this interpretation and the perspectives for the detection of other young sources in gamma-rays.

The CSO PKS 1718-649 In Gamma-Rays With Fermi-LAT

L. Ostorero;
2016-01-01

Abstract

We report the detection (> 5sigma ) with Fermi-LAT of gamma-ray emission from the nearby (z = 0.014) radio galaxy, PKS 1718-649. This is the first detection in gamma-rays of a bona fide Compact Symmetric Object, a class of sources that are thought to represent the first stage in the evolution of extragalactic radio sources. A detection in the gamma-ray band is a clear indication of a non-thermal high-energy component and provides us with important insights on the physical conditions of expanding young radio sources. The symmetric radio morphology indicates that the source is seen at a large inclination angle and disfavors a contribution of the jet boosted emission. The steep gamma-ray spectrum and steady faint emission are consistent with the scenario of isotropic gamma-ray emission from the compact (<2pc) radio lobes, as proposed by models of expanding young radio sources. We discuss this interpretation and the perspectives for the detection of other young sources in gamma-rays.
Active Galactic Nuclei 12: A Multi-Messenger Perspective (AGN12)
Napoli, Italy
26-29 September 2016
Proceedings of the conference "Active Galactic Nuclei 12: A Multi-Messenger Perspective"
1
12
http://adsabs.harvard.edu/abs/2016agnt.confE..60M
https://zenodo.org/record/163821#.Wlzms_ZrxoA
Migliori, G.; Siemiginowska, A.; Sobolewska, M.; Loh, A.; Corbel, S.; Ostorero, L.; Stawarz, L.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1657606
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