Fermi/LAT Study of Gamma-Ray Emission in the Direction of the Monoceros Loop Supernova Remnant

H. Katagiri , S. Sugiyama , M. Ackermann , J. Ballet (1) , J. M. Casandjian (1) , Y. Hanabata , J. W. Hewitt , M. Kerr , H. Kubo , M. Lemoine-Goumard (2) , P. S. Ray

1 AIM (UMR_7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
2 UB - Université de Bordeaux

We present an analysis of the gamma-ray measurements by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope in the region of the supernova remnant (SNR) Monoceros Loop (G205.5+0.5). The brightest gamma-ray peak is spatially correlated with the Rosette Nebula, which is a molecular cloud complex adjacent to the southeast edge of the SNR. After subtraction of this emission by spatial modeling, the gamma-ray emission from the SNR emerges, which is extended and fit by a Gaussian spatial template. The gamma-ray spectra are significantly better reproduced by a curved shape than a simple power law. The luminosities between 0.2 and 300 GeV are ∼ 4× {10}³⁴ erg s^-1 for the SNR and ∼ 3× {10}³⁴ erg s^-1 for the Rosette Nebula, respectively. We argue that the gamma-rays likely originate from the interactions of particles accelerated in the SNR. The decay of neutral pions produced in nucleon-nucleon interactions of accelerated hadrons with interstellar gas provides a reasonable explanation for the gamma-ray emission of both the Rosette Nebula and the Monoceros SNR.

Keywords: acceleration of particles; cosmic rays; gamma-rays: ISM; ISM: individual objects: the Monoceros Loop; ISM: supernova remnants; Astrophysics - High Energy Astrophysical Phenomena

Domains: Sciences of the Universe [physics]; Astrophysics [astro-ph]

H. Katagiri, S. Sugiyama, M. Ackermann, J. Ballet, J. M. Casandjian, et al.. Fermi/LAT Study of Gamma-Ray Emission in the Direction of the Monoceros Loop Supernova Remnant. The Astrophysical Journal, 2016, 831, ⟨10.3847/0004-637X/831/1/106⟩. ⟨insu-03746215⟩