The Morphology of Hadronic Emission Models for the Gamma-Ray Source at the Galactic Center
Abstract
Recently, detections of a high-energy γ-ray source at the position of the Galactic center have been reported by multiple γ-ray telescopes, spanning the energy range between 100 MeV and 100 TeV. Analysis of these signals strongly suggests the TeV emission to have a morphology consistent with a point source up to the angular resolution of the HESS telescope (approximately 3 pc), while the point-source nature of the GeV emission is currently unsettled, with indications that it may be spatially extended. In the case that the emission is hadronic and in a steady state, we show that the expected γ-ray morphology is dominated by the distribution of target gas, rather than by details of cosmic-ray injection and propagation. Specifically, we expect a significant portion of hadronic emission to coincide with the position of the circumnuclear ring, which resides between 1 and 3 pc from the Galactic center. We note that the upcoming Cherenkov Telescope Array (CTA) will be able to observe conclusive correlations between the morphology of the TeV γ-ray source and the observed gas density, convincingly confirming or ruling out a hadronic origin for the γ-ray emission.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 2012
- DOI:
- 10.1088/0004-637X/753/1/41
- arXiv:
- arXiv:1203.3539
- Bibcode:
- 2012ApJ...753...41L
- Keywords:
-
- cosmic rays;
- Galaxy: center;
- gamma rays: galaxies;
- gamma rays: general;
- gamma rays: ISM;
- ISM: abundances;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Astrophysics of Galaxies;
- High Energy Physics - Phenomenology
- E-Print:
- 7 pages, 3 figures, Submitted to ApJ