2007A&A...473..351C


C.D.S. - SIMBAD4 rel 1.7 - 2021.03.01CET20:18:10

2007A&A...473..351C - Astronomy and Astrophysics, volume 473, 351-356 (2007/10-2)

Diffuse gamma-ray emission from the Galactic Center - a multiple energy injection model.

CHENG K.S., CHERNYSHOV D.O. and DOGIEL V.A.

Abstract (from CDS):

We suggest that the energy source of the observed diffuse gamma-ray emission from the direction of the Galactic center is the Galactic black hole Sgr A*, which becomes active when a star is captured at a rate of ∼10–5yr–1. Subsequently the star is tidally disrupted and its matter is accreted into the black hole. During the active phase relativistic protons with a characteristic energy ∼6x1052erg per capture are ejected. Over 90% of these relativistic protons disappear due to proton-proton collisions on a timescale τpp ∼104 years in the small central bulge region with radius ∼50pc within Sgr A*, where the density is ≥103cm–3. The gamma-ray intensity, which results from the decay of neutral pions produced by proton-proton collisions, decreases according to e–t/τpp_^, where t is the time after last stellar capture. Less than 5% of relativistic protons escaped from the central bulge region can survive and maintain their energy for >107 years due to much lower gas density outside, where the gas density can drop to ∼1cm–3. They can diffuse to a ∼500pc region before disappearing due to proton-proton collisions. The observed diffuse GeV gamma-rays resulting from the decay of neutral pions produced via collision between these escaped protons and the gas in this region is expected to be insensitive to time in the multi-injection model with the characteristic injection rate of 10–5yr–1. Our model calculated GeV and 511keV gamma-ray intensities are consistent with the observed results of EGRET and INTEGRAL, however, our calculated inflight annihilation rate cannot produce sufficient intensity to explain the COMPTEL data.

Abstract Copyright:

Journal keyword(s): cosmic rays - Galaxy: center - gamma rays: theory - black hole physics - radiation mechanisms: non-thermal

Simbad objects: 6

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Number of rows : 6

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 Mrk 421 BLL 11 04 27.3139210166 +38 12 31.798324828   13.50 12.90 8.31   ~ 2427 1
2 4C 39.49 BLL 16 53 52.21668494 +39 45 36.6089458 14.09 14.15 13.29 8.26   ~ 1954 2
3 3FHL J1746.2-2852 LXB 17 44 33.09 -28 44 27.0           ~ 497 0
4 GAL 000.0+00.0 gam 17 45 39.60213 -29 00 22.0000           ~ 11999 0
5 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 3598 3
6 NAME Galactic Bulge reg ~ ~           ~ 3531 0

    Equat.    Gal    SGal    Ecl

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