GeV emission in the region of HESS J1809-193 and HESS J1813-178: is HESS J1809-193 a proton pevatron?

Abstract

HESS J1809-193 is an unidentified TeV source discovered by the High Energy Stereoscopic System and originally classified as a pulsar wind nebula (PWN) candidate associated with the pulsar PSR J1809-1917. However, a recent study of deep radio observations and the interstellar medium near the source has found evidence for a hadronic scenario for the gamma-rays. Here, a detailed study of the GeV emission in the region using data from the \emph{Fermi} LAT is presented. The GeV emission has an extended morphology in the region of the TeV emission and the overall spectrum can be accounted for by a cosmic ray population having a simple power-law spectrum with energies extending up to 1 PeV. However, the spectrum at tens of TeV should be observed more deeply in the future to confirm its hadronic nature, and other scenarios involving combinations of leptonic and hadronic emission from several of the known supernova remnants in the region cannot be ruled out. The nearby TeV source HESS J1813-178, thought to be a PWN, is also studied in detail at GeV energies and we find a region of significant emission which is much more extended than the TeV emission and whose spectrum is softer than expected from a PWN but similar to those seen in several star forming regions that are believed to accelerate protons. There is marginal evidence for a GeV point source at the location of the X-ray PWN, beside the extended emission.

To appear in ApJ

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Cited by in corpus (14)

• Fermi Large Area Telescope Fourth Source Catalog
• The Highest Energy HAWC Sources are Likely Leptonic and Powered by Pulsars
• HESS J1809$-$193: a halo of escaped electrons around a pulsar wind nebula?
• Connecting the ISM to TeV PWNe and PWNe candidates
• Galactic Observatory Science with the ASTRI Mini-Array at the Observatorio del Teide
• The Variable Pulsar Wind Nebula of PSR J1809-1917
• Search for new cosmic-ray acceleration sites within the 4FGL catalog Galactic plane sources
• Study of maximum electron energy of sub-PeV pulsar wind nebulae by multiwavelength modelling
• Revisiting the Chandra Observation on the Region of PSR J1809-1917: Indication of an X-ray Halo and Implication for the Origin of HESS J1809-193
• Revealing a new region of gamma-ray emission in the vicinity of HESS J1825-137
• HESS J1809-193: Gamma-Ray Emission by Cosmic Rays from Past Explosion
• Exploring the possible gluon condensation signature in gamma-ray emission from pulsars
• GeV emission in the region of Vela: a new view of the supernova remnant
• Unveiling extended gamma-ray emission around HESS J1813-178