Electron-positron pair production near the Galactic Centre and the 511 keV emission line

Abstract

Recent observations indicate that a high production rate of positrons (strong 511 keV line) and a significant amount of excess GeV gamma-ray exist in our Galactic bulge. The latter issue can be explained by $\sim 40$ GeV dark matter annihilation through $b\bar{b}$ channel while the former one remains a mystery. On the other hand, recent studies reveal that a large amount of high density gas might exist near the Galactic Centre million years ago to account for the young, massive stars extending from 0.04 pc - 7 pc. In this article, I propose a new scenario and show that the 40 GeV dark matter annihilation model can also explain the required positron production rate (511 keV line) in the bulge due to the existence of the high density gas cloud near the supermassive black hole long time ago.

Accepted for publication in MNRAS Letters

References in corpus (8)

• The 3rd IBIS/ISGRI soft gamma-ray survey catalog
• Possible Evidence For Dark Matter Annihilation In The Inner Milky Way From The Fermi Gamma Ray Space Telescope
• Continuum gamma-ray emission from light dark matter positrons and electrons
• Fitting formulae for photon spectra from WIMP annihilation
• Photon spectra from WIMP annihilation
• Radio constraints on dark matter annihilation in the galactic halo and its substructures
• Signatures of Young Star Formation Activity Within Two Parsecs of Sgr A*
• A possible link between the GeV excess and the 511 keV emission line in the Galactic Centre

Cited by in corpus (2)

• Ruling out the light WIMP explanation of the galactic 511 keV line
• Constraining dark matter by the 511 keV line