On the high-energy gamma-ray signature of cosmic-ray sources

Abstract

view Abstract Citations (19) References (40) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS On the High-Energy Gamma-Ray Signature of Cosmic-Ray Sources Ormes, J. F. ; Ozel, M. E. ; Morris, D. J. Abstract If cosmic rays are accelerated by strong shocks, then cosmic-ray sources should be characterized by spectra, dN/dE is proportional to p^-(2.0-2.2)^, reflecting the strength of those shocks. This is expected from the "standard leaky box" model of cosmic-ray propagation in which the source spectra are harder than the observed spectra because higher energy particles have shorter residence times in the Galactic magnetic fields. Furthermore, data on cosmic-ray nucleons suggest that these sources are surrounded by a shroud of material. Such sources should be observable as point sources of γ-rays; the enhanced cosmic-ray intensity due to the local acceleration of particles should make these sources stand out against the general Galactic background. We present here the characteristics of such sources and model their γ-ray emissivity. Sources which might correspond to acceleration by supernova shocks in "average" interstellar conditions and deep within giant molecular clouds are considered. These considerations led us to examine the consequences of dropping the common assumption that the cosmic-ray spectrum at the sources is the same as that observed at Earth. Spectral effects which can be related to the depth of the material shroud and the population of accelerated particles are explored using these simulations and will be described. The results are compared with the COS B catalog of γ-ray sources, and the implications for the underlying particle populations and source mechanisms are discussed. Publication: The Astrophysical Journal Pub Date: November 1988 DOI: 10.1086/166873 Bibcode: 1988ApJ...334..722O Keywords: Cosmic Rays; Gamma Ray Astronomy; Particle Acceleration; Shock Wave Propagation; Energetic Particles; Milky Way Galaxy; Monte Carlo Method; Spectrum Analysis; Supernovae; Space Radiation; COSMIC RAYS: GENERAL; GAMMA RAYS: GENERAL; PARTICLE ACCELERATION; SHOCK WAVES full text sources ADS | data products SIMBAD (16) NED (1)