Diffusive cosmic-ray acceleration in sagittarius A

M. Fatuzzo, Fulvio Melia

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Together, Fermi-LAT and HESS have revealed the presence of an unusual GeV-TeV source coincident with Sgr A* at the Galactic center. Its high-energy emission appears to be bimodal, hinting at an energizing process more sophisticated than mere shock acceleration. It has been suggested that this may be evidence of strong, rapid variability, as required if Sgr A*'s emission were responsible for the fluorescent X-ray echoes detected in nearby molecular clouds. In this Letter, however, we show that stochastic acceleration in a more realistic two-phase environment surrounding the central black hole can accommodate Sgr A*'s high-energy spectrum quite well. We therefore suggest that the Fermi-HESS data alone do not necessarily provide evidence for strong variability in Sgr A*.

Original languageEnglish (US)
Article numberL16
JournalAstrophysical Journal Letters
Volume757
Issue number1
DOIs
StatePublished - Sep 20 2012

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cosmic ray
cosmic rays
molecular clouds
energy
echoes
energy spectra
shock
x rays

Keywords

  • acceleration of particles
  • cosmic rays
  • Galaxy: center
  • gamma rays: general
  • radiation mechanisms: non-thermal

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Diffusive cosmic-ray acceleration in sagittarius A. / Fatuzzo, M.; Melia, Fulvio.

In: Astrophysical Journal Letters, Vol. 757, No. 1, L16, 20.09.2012.

Research output: Contribution to journalArticle

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