The spatial distribution of dark matter annihilation originating from a gamma-ray line signal
Abstract
The GeV-TeV γ-ray line signal is the smoking gun signature of dark matter annihilation or decay. The detection of such a signal is one of the main targets of some space-based telescopes, including Fermi-LAT and the upcoming missions CALET, DAMPE and Gamma-400. An important feature of γ-ray line photons that originate from dark-matter-annihilation is that they are concentrated at the center of the Galaxy. So far, no reliable γ-ray line has been detected by Fermi-LAT, and the upper limits on the cross section of annihilation into γ-rays have been reported. We use these upper limits to estimate the “maximal” number of γ-ray line photons detectable for Fermi-LAT, DAMPE and Gamma-400, and then investigate the spatial distribution of these photons. We show that the center of the distribution will usually be offset from the Galactic center (Sgr A*) due to the limited statistics. Such a result is almost independent of models of the dark matter distribution, and will render the reconstruction of the dark matter distribution with the γ-ray line signal very challenging for foreseeable space-based detectors.
- Publication:
-
Research in Astronomy and Astrophysics
- Pub Date:
- May 2014
- DOI:
- 10.1088/1674-4527/14/5/002
- arXiv:
- arXiv:1312.0357
- Bibcode:
- 2014RAA....14..520L
- Keywords:
-
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- Typos corrected