GRBs and the 511 keV emission of the Galactic bulge - IN2P3 - Institut national de physique nucléaire et de physique des particules Access content directly
Journal Articles Astronomy and Astrophysics - A&A Year : 2005

GRBs and the 511 keV emission of the Galactic bulge

Abstract

We consider the phenomenology of the 511 keV emission in the Galactic bulge, as recently observed by INTEGRAL, and propose a model is which the positrons are produced by gamma-ray bursts (GRB) associated with mini starbursts in the central molecular zone (CMZ). We show that the positrons can easily diffuse across the bulge on timescales of about 10^7 yr, and that their injection rate by GRBs is compatible with the observed fluxes if the mean time between two GRBs in the bulge is about 8 10^4 yr x E_GRB_51. We also explain the low disk-to-bulge emission ratio by noting that positrons from GRBs in the Galactic disk should annihilate on timescales of < 10^4 yr in the dense shell of the underlying supernova remnant, after the radiative transition, while the remnants of GRBs occurring in the hot, low-density medium produced by recurrent starbursts in the CMZ become subsonic before they can form a radiative shell, allowing the positrons to escape and fill the whole Galactic bulge. If the mean time between GRBs is smaller than 10^4 E_51 yr, INTEGRAL should be able to detect the (localized) 511 keV emission associated with one or a few GRB explosions in the disk.
Fichier principal
Vignette du fichier
aa2215.pdf (147.7 Ko) Télécharger le fichier
Origin Publisher files allowed on an open archive

Dates and versions

in2p3-00023426 , version 1 (01-03-2021)

Identifiers

Cite

E. Parizot, M. Cassé, R. Lehoucq, J. C. Paul. GRBs and the 511 keV emission of the Galactic bulge. Astronomy and Astrophysics - A&A, 2005, 432, pp.889-894. ⟨10.1051/0004-6361:20042215⟩. ⟨in2p3-00023426⟩
29 View
0 Download

Altmetric

Share

Gmail Mastodon Facebook X LinkedIn More