Discovery of an extended source of gamma-ray emission in the Southern Hemisphere

Abstract

We report the discovery of a $\sim$ $3.4\degr$-wide region of high-energy emission in data from the \emph{Fermi} LAT satellite. The centroid of the emission is located in the Southern Hemisphere sky, a few degrees away from the plane of the Galaxy at the Galactic coordinates l=350.6$\degr$, b=-4.7$\degr$. It shows a hard spectrum that is compatible with a simple power-law, $\frac{dN}{dE}\propto E^{-\Gamma }$, in the energy range 0.7--500 GeV, with a spectral index $Γ= 1.68 \pm 0.04_{\mbox{stat}} \pm 0.1_{\mbox{sys}}$. The integrated source photon flux above 0.7 GeV is $(4.71 \pm 0.49_{\mbox{stat}}\pm 2.13_{\mbox{sys}}) \times 10^{-9}$ cm${}^{-2}$ s${}^{-1}$. We discuss several hypotheses for the nature of the source, particularly that the emission comes from the shell of an unknown supernova remnant.

MNRAS published online 2017 October

References in corpus (17)

• Giant Gamma-ray Bubbles from Fermi-LAT: AGN Activity or Bipolar Galactic Wind?
• Detection of the Characteristic Pion-Decay Signature in Supernova Remnants
• The Third Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope
• Development of the Model of Galactic Interstellar Emission for Standard Point-Source Analysis of Fermi Large Area Telescope Data
• 3FHL: The Third Catalog of Hard Fermi-LAT Sources
• The Spectrum and Morphology of the Fermi Bubbles
• 2FHL: The Second Catalog of Hard Fermi-LAT Sources
• The 1st Fermi Lat Supernova Remnant Catalog
• Observations of the young supernova remnant RX J1713.7-3946 with the Fermi Large Area Telescope
• Fermi Establishes Classical Novae as a Distinct Class of Gamma-Ray Sources
• A Dynamical Model for the Evolution of a Pulsar Wind Nebula inside a Non-Radiative Supernova Remnant
• Modeling the Multi-Wavelength Emission of Shell-Type Supernova Remnant RX J1713.7-3946
• A search for new supernova remnant shells in the Galactic plane with H.E.S.S
• H.E.S.S. detection of TeV emission from the interaction region between the supernova remnant G349.7+0.2 and a molecular cloud
• Discovery of a new supernova remnant G150.3+4.5
• Analysis of GeV-band gamma-ray emission from SNR RX J1713.7-3946
• Discovery of the supernova remnant G351.0-5.4

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• G279.0+1.1: a new extended source of high-energy gamma rays
• HAWC and Fermi-LAT Detection of Extended Emission from the Unidentified Source 2HWC J2006+341
• Revealing a new region of gamma-ray emission in the vicinity of HESS J1825-137