Diffuse TeV emission at the Galactic Centre

Elizabeth Wommer, Fulvio Melia, Marco Fatuzzo

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

The High-Energy Stereoscopic System (HESS) has detected intense diffuse TeV emission correlated with the distribution of molecular gas along the Galactic ridge at the centre of our Galaxy. Earlier HESS observations of this region had already revealed the presence of several point sources at these energies, one of them (HESS J1745-290) coincident with the supermassive black hole Sagittarius A*. It is still not entirely clear what the origin of the TeV emission is, nor even whether it is due to hadronic or leptonic interactions. It is reasonable to suppose, however, that at least for the diffuse emission, the tight correlation of the intensity distribution with the molecular gas indicates a pionic-decay process involving relativistic protons. In this paper, we explore the possible source(s) of energetic hadrons at the Galactic Centre, and their propagation through a turbulent medium. We conclude that though Sagittarius A* itself may be the source of cosmic rays producing the emission in HESS J1745-290, it cannot be responsible for the diffuse emission farther out. A distribution of point sources, such as pulsar wind nebulae dispersed along the Galactic plane, similarly do not produce a TeV emission profile consistent with the HESS map. We conclude that only a relativistic proton distribution accelerated throughout the intercloud medium can account for the TeV emission profile measured with HESS.

Original languageEnglish (US)
Pages (from-to)987-997
Number of pages11
JournalMonthly Notices of the Royal Astronomical Society
Volume387
Issue number3
DOIs
StatePublished - Jul 2008

Fingerprint

energy
molecular gases
point sources
point source
protons
profiles
nebulae
gas
hadrons
pulsars
cosmic ray
ridges
cosmic rays
energetics
galaxies
propagation
distribution
decay
interactions

Keywords

  • Black hole physics
  • Cosmic rays
  • Galaxy: centre
  • Magnetic fields
  • Turbulence

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Diffuse TeV emission at the Galactic Centre. / Wommer, Elizabeth; Melia, Fulvio; Fatuzzo, Marco.

In: Monthly Notices of the Royal Astronomical Society, Vol. 387, No. 3, 07.2008, p. 987-997.

Research output: Contribution to journalArticle

Wommer, Elizabeth ; Melia, Fulvio ; Fatuzzo, Marco. / Diffuse TeV emission at the Galactic Centre. In: Monthly Notices of the Royal Astronomical Society. 2008 ; Vol. 387, No. 3. pp. 987-997.
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