The GeV counterpart of VER J2019+407 in the northern shell of the supernova remnant G78.2+2.1 ($\gamma$ Cygni)

Abstract

Analysis of gamma-ray emission from the supernova remnant G78.2+2.1 ($\gamma$ Cygni) with 7.2 years of cumulative data from the Fermi-LAT telescope shows a distinct hard, bright and extended component to the north of the shell coincident with the known TeV source VER J2019+407. In the GeV-TeV energy range its spectrum is best described by a broken power-law with indices 1.8 below a break energy of 71 GeV and 2.5 above the break. A broadband spectral energy distribution is assembled and different scenarios for the origin of the gamma-rays are explored. Both hadronic and leptonic mechanisms are able to account for the GeV-TeV observations. In the leptonic framework, a superposition of inverse Compton and nonthermal bremsstrahlung emissions is needed whereas the hadronic scenario requires a cosmic ray population described by a broken power-law distribution with a relatively hard spectral index of $\sim 1.8$ below a break particle energy of 0.45 TeV. In addition, the neutrino flux expected from cosmic ray interactions is calculated.

8 pages and 4 figures. Accepted for publication in ApJ

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Cited by in corpus (18)

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• Search for extended sources in the Galactic Plane using 6 years of Fermi-Large Area Telescope Pass 8 data above 10 GeV
• A Very High Energy $\gamma$-Ray Survey towards the Cygnus Region of the Galaxy
• ASTRI Mini-Array Core Science at the Observatorio del Teide
• The Second AGILE Catalog of Gamma-Ray Sources
• Neutrino, $\gamma$-ray and cosmic ray fluxes from the core of the closest radio galaxies
• Observational constraints on the maximum energies of accelerated particles in supernova remnants: low maximum energies and a large variety
• Galactic and Extragalactic Sources of Very High Energy Gamma-rays
• Study on the escape timescale of high-energy particles from supernova remnants through thermal X-ray properties
• Study of the GeV to TeV morphology of the $\gamma$-Cygni SNR (G78.2+2.1) with MAGIC and Fermi-LAT
• Search for new cosmic-ray acceleration sites within the 4FGL catalog Galactic plane sources
• Telescope Concepts in Gamma-Ray Astronomy
• Analysis of Fermi-LAT observations, UHECRs and neutrinos from the radio galaxy Centaurus B
• AGILE study of the gamma-ray emission from the SNR G78.2+2.1 (Gamma Cygni)
• A Central Compact Object in Kes 79: The hypercritical regime and neutrino expectation
• Exploring the region encompassing gamma Cygni SNR and MAGIC J2019+408 with the GMRT at 325 and 610 MHz
• GeV emission in the region of the supernova remnant G51.26+0.11
• Fermi LAT observation of VER J2019+407