TeV Gamma Rays Expected from Supernova Remnants in Different Uniform Interstellar Media

Abstract

Calculations of the expected TeV $\gamma$-ray emission, produced by accelerated cosmic rays (CRs) in nuclear collisions, from supernova remnants evolving in a uniform interstellar medium (ISM) are presented. The aim is to study the sensitivity of $\gamma$-ray production to a physical parameter set. Apart from its general proportionality to N_H, it is shown that the $\gamma$-ray production essentially depends upon the ratio of the CR diffusion coefficient $\kappa$ to a critical value ${\kappa }_{crit}=10(B_0/5\mu G)(N_H/0.3{cm}^{-3}{)}^{-1/3}{\kappa }_B$, where B_0 and N_H are the magnetic field and hydrogen number density of the ISM, and ${\kappa }_B$ denotes the Bohm diffusion coefficient. If $\kappa$ is of the same order or lower than ${\kappa }_{crit}$, then the peak TeV $\gamma$-ray flux in the Sedov evolutionary phase, normalized to a distance of 1 kpc, is about 10^{-10}(N_H/0.3 {cm}^{-3}) photons cm^{-2} s^{-1}. For a CR diffusion coefficient that is significantly larger than ${\kappa }_{crit}$, the CR cutoff energy is less than 10 TeV and the expected $\gamma$-ray flux at 1 TeV is considerably below the presently detectable level of 10^{-12} photons cm^{-2} s^{-1}. The same is of course true for a SNR in the rarified, so-called hot ISM.

9 pages, 2 figures, to appear in Astroparticle Physics

Cited by in corpus (8)

• Evidence for TeV gamma ray emission from Cassiopeia A
• Radio emission from Supernova Remnants
• Theory of cosmic ray production in the supernova remnant RX J1713.7-3946
• High-energy Cosmic Rays
• Gamma-ray emission from Cassiopeia A produced by accelerated cosmic rays
• A search for TeV gamma-ray emission from SNRs, pulsars and unidentified GeV sources in the Galactic plane in the longitude range between -2 deg and 85 deg
• The nature of the 'knee' in the cosmic ray energy spectrum
• Tests of Galactic Cosmic Ray Source Models