Gamma Rays frim the Galactic Centre

Abstract

Recent results from the HESS gamma ray telescope have shown the presence of both a diffuse, extended, flux of gamma rays above ~0.4 TeV and discrete sources in and near the Galactic Centre. Here, we put forward a possible explanation in terms of the diffusion of cosmic ray protons from a succession of supernova remnants (SNR) in the SgrA* region of the Galaxy plus a contribution from SNR in the rest of the Galactic Centre Region, to be called the Galactic Centre Ridge (GCR). Protons are favoured over electrons because the mG magnetic fields in the Region will attenuate energetic electrons severely. Prominent features are the need for 'anomalous diffusion' of the protons in the whole region and the adoption of low efficiency for SNR acceleration in the high density regions. The latter is related by us to the well-known low 'cosmic ray gradient' in the Galaxy. A corroborating feature is the close correlation of inferred cosmic ray intensity with the smoothed intensity of 5 GHZ radio radiation. We attribute this to the presence of the SNR in the GCR.

21 pages, 7 figures, accepted by J. Phys. G: Nucl. Part. Phys

References in corpus (12)

• The Milky Way in Molecular Clouds: A New Complete CO Survey
• Discovery of Very-High-Energy Gamma-Rays from the Galactic Centre Ridge
• Very high energy gamma rays from the direction of Sagittarius A*
• Detection of Sub-TeV Gamma-Rays from the Galactic Center Direction by CANGAROO-II
• TeV Gamma-Ray Observations of the Galactic Center
• Observation of Gamma Rays from the Galactic Center with the MAGIC Telescope
• The gradient of diffuse gamma-ray emission in the Galaxy
• The knee in galactic cosmic ray spectrum and variety in supernovae
• Cosmic Ray Acceleration by Spiral Shocks in the Galactic Wind
• Properties of the Interstellar Medium and the Propagation of Cosmic Rays in the Galaxy
• Limits on diffusive shock acceleration in dense and incompletely ionised media
• The visibility of shell-type supernova remnants in gamma rays

Cited by in corpus (6)

• Wild at Heart:-The Particle Astrophysics of the Galactic Centre
• Gamma-Rays and the Far-Infrared-Radio Continuum Correlation Reveal a Powerful Galactic Centre Wind
• On the Galactic Center Being the Main Source of Galactic Cosmic Rays as Evidenced by Recent Cosmic Ray and Gamma Ray Observations
• Obtaining the diffusion coefficient for cosmic ray propagation in the Galactic Centre Ridge through time-dependent simulations of their gamma-ray emission
• High-(Energy)-Lights -- The Very High Energy Gamma-Ray Sky
• Simulation of Cosmic Ray propagation in the Galactic Centre Ridge in Accordance with Observed VHE gamma-ray Emission