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On the origin of the 511-keV emission in the galactic centre

On the origin of the 511-keV emission in the galactic centre
On the origin of the 511-keV emission in the galactic centre
Diffuse 511-keV line emission, from the annihilation of cold positrons, has been observed in the direction of the Galactic Centre for more than 30yr. The latest high-resolution maps of this emission produced by the SPI instrument on INTEGRAL suggest at least one component of the emission is spatially coincident with the distribution of ~70 luminous, low-mass X-ray binaries detected in the soft gamma-ray band. The X-ray band, however, is generally a more sensitive probe of X-ray binary populations. Recent X-ray surveys of the Galactic Centre have discovered a much larger population (>4000) of faint, hard X-ray point sources. We investigate the possibility that the positrons observed in the direction of the Galactic Centre originate in pair-dominated jets generated by this population of fainter accretion-powered X-ray binaries. We also consider briefly whether such sources could account for unexplained diffuse emission associated with the Galactic Centre in the microwave (the Wilkinson Microwave Anisotropy Probe 'haze') and at other wavelengths. Finally, we point out several unresolved problems in associating Galactic Centre 511-keV emission with the brightest X-ray binaries.
acceleration of particles, black hole physics, galaxy: centre, dark matter, X-rays: binaries
0035-8711
1115-1123
Bandyopadhyay, Reba M.
6a9d3fc5-7a0b-4557-ac27-5de72da14873
Silk, Joseph
500ef2a0-9489-43ed-858e-56f09045e49e
Taylor, James E.
4c3684b9-601c-49c2-8282-6211437a0421
Maccarone, Thomas J.
27e6101c-8fa4-41db-ba75-d2ee3d1a0c53
Bandyopadhyay, Reba M.
6a9d3fc5-7a0b-4557-ac27-5de72da14873
Silk, Joseph
500ef2a0-9489-43ed-858e-56f09045e49e
Taylor, James E.
4c3684b9-601c-49c2-8282-6211437a0421
Maccarone, Thomas J.
27e6101c-8fa4-41db-ba75-d2ee3d1a0c53

Bandyopadhyay, Reba M., Silk, Joseph, Taylor, James E. and Maccarone, Thomas J. (2009) On the origin of the 511-keV emission in the galactic centre. Monthly Notices of the Royal Astronomical Society, 392 (3), 1115-1123. (doi:10.1111/j.1365-2966.2008.14113.x).

Record type: Article

Abstract

Diffuse 511-keV line emission, from the annihilation of cold positrons, has been observed in the direction of the Galactic Centre for more than 30yr. The latest high-resolution maps of this emission produced by the SPI instrument on INTEGRAL suggest at least one component of the emission is spatially coincident with the distribution of ~70 luminous, low-mass X-ray binaries detected in the soft gamma-ray band. The X-ray band, however, is generally a more sensitive probe of X-ray binary populations. Recent X-ray surveys of the Galactic Centre have discovered a much larger population (>4000) of faint, hard X-ray point sources. We investigate the possibility that the positrons observed in the direction of the Galactic Centre originate in pair-dominated jets generated by this population of fainter accretion-powered X-ray binaries. We also consider briefly whether such sources could account for unexplained diffuse emission associated with the Galactic Centre in the microwave (the Wilkinson Microwave Anisotropy Probe 'haze') and at other wavelengths. Finally, we point out several unresolved problems in associating Galactic Centre 511-keV emission with the brightest X-ray binaries.

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More information

Published date: January 2009
Keywords: acceleration of particles, black hole physics, galaxy: centre, dark matter, X-rays: binaries

Identifiers

Local EPrints ID: 79558
URI: https://eprints.soton.ac.uk/id/eprint/79558
ISSN: 0035-8711
PURE UUID: 737d10db-2200-4cde-87a6-d884168c3a31

Catalogue record

Date deposited: 17 Mar 2010
Last modified: 16 Jul 2017 16:30

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