A kinship between the EGRET supernova remnants and sagittarius a East

Marco Fatuzzo, Fulvio Melia

Research output: Contribution to journalArticlepeer-review

43 Scopus citations


Sgr A East appears to be a single, mixed-morphology 10,000 yr old supernova remnant (SNR) at the Galactic center. It also appears to belong to a class of remnants that have been observed and detected at 1720 MHz, the transition frequency of OH maser emission. However, if the EGRET source 3EG J1746-2852, coincident with the Galactic center, is itself associated with this object, it would endow it with a γ-ray luminosity almost 2 orders of magnitude greater than that of the other EGRET-detected SNRs. We here reconsider the viability of a pion-production mechanism as the source of the broadband emission observed from Sgr A East, and show that what connects these objects - and ultimately also accounts for their different γ-ray emissivity - is the very important interaction between the expanding SNR shell and the surrounding molecular cloud environment. The singularly high γ-ray luminosity of Sgr A East, as well as its unusually steep radio spectral index, can thereby be attributed to the high-density (nH = 103 cm-3), strongly magnetized (B ∼ 0.18 mG) environment in which it is located.

Original languageEnglish (US)
Pages (from-to)1035-1043
Number of pages9
JournalAstrophysical Journal
Issue number2 I
StatePublished - Oct 20 2003


  • Acceleration of particles
  • Cosmic rays
  • Galaxy: center
  • Gamma rays: theory
  • Radiation mechanisms: nonthermal
  • Supernova remnants

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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