Diffusive cosmic-ray acceleration in sagittarius A

M. Fatuzzo, F. Melia

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


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
Issue number1
StatePublished - Sep 20 2012


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

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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