The high-energy gamma-ray detection of G73.9+0.9, a supernova remnant interacting with a molecular cloud

Abstract

We have analysed the Fermi LAT data on the SNR G73.9+0.9. We have confirmed a previous detection of high-energy gamma-rays from this source at a high significance of $\simeq 12\sigma$. The observed spectrum shows a significant curvature, peaking in $E{F}_E$ at $\sim$1 GeV. We have also calculated the flux upper limits in the mm-wavelength and X-ray ranges from Planck and XMM-Newton, respectively. We have inspected the intensity of the CO (1$\to$0) emission line and found a large peak at a velocity range corresponding to the previously estimated source distance of $\sim$4 kpc, which may indicate an association between a molecular cloud and the SNR. The gamma-ray emission appears due to interaction of accelerated particles within the SNR with the matter of the cloud. The most likely radiative process responsible for the gamma-ray emission is decay of neutral pions produced in ion-ion collisions. While a dominant leptonic origin of this emission can be ruled out, the relativistic electron population related to the observed radio flux will necessarily lead to a certain level of bremsstrahlung gamma-ray emission. Based on this broad-band modelling, we have developed a method to estimate the magnetic field, yielding $B\ge 80\mu$G at our best estimate of the molecular cloud density (or less at a lower density). G73.9+0.9 appears similar, though somewhat weaker, to other SNRs interacting with a local dense medium detected by the LAT.

MNRAS, in press

References in corpus (4)

• Parametrization of gamma-ray production cross-sections for pp interactions in a broad proton energy range from the kinematic threshold to PeV energies
• Mechanism for spectral break in cosmic ray proton spectrum from Supernova remnant W44
• Discovery of New Interacting Supernova Remnants in the Inner Galaxy
• The First Fermi-LAT SNR Catalog SNR and Cosmic Ray Implications

Cited by in corpus (11)

• Detection of gamma rays of likely jet origin in Cygnus X-1
• Evolution of high-energy particle distribution in Supernova Remnants
• Distances, Radial Distribution and Total Number of Galactic Supernova Remnants
• A Very High Energy $\gamma$-Ray Survey towards the Cygnus Region of the Galaxy
• A comprehensive study of high-energy gamma-ray and radio emission from Cyg X-3
• Distances of Galactic Supernova Remnants Using Red Clump Stars
• Observational constraints on the maximum energies of accelerated particles in supernova remnants: low maximum energies and a large variety
• Curvature in the very-high energy gamma-ray spectrum of M87
• Study on the escape timescale of high-energy particles from supernova remnants through thermal X-ray properties
• The Age Evolution of the Radio Morphology of Supernova Remnants
• Long-term evolution of non-thermal emission from Type Ia and core-collapse supernova remnants in a diversified circumstellar medium