The ASCA catalog of potential X-ray counterparts of GeV sources

Mallory S.E. Roberts, Roger W. Romani, Nobuyuki Kawai

Research output: Contribution to journalArticlepeer-review


We present a catalog of 2-10 keV ASCA Gas Imaging Spectrometer images of fields containing bright sources of GeV emission. The images cover ~ 85% of the 95% confidence position contour for 28 of the 30 sources with > 1 GeV fluxes above 4 × 10-8 ph cm-2 s-1. We find an excess of hard X-ray sources with F2-10keV ≳ 10-12 ergs cm-2 s-1 positionally coincident with unidentified sources of GeV emission. We comment on radio-loud and radio-quiet pulsar candidates, as well as several SNRs and massive binaries as possible sources of the GeV emission. We also find evidence for a class of variable γ-ray sources associated with extended regions of hard X-ray emission, and propose that for these sources, a significant percentage of the γ-ray emission is generated in synchrotron nebulae surrounding fast, young pulsars.

Original languageEnglish (US)
Pages (from-to)451-465
Number of pages15
JournalAstrophysical Journal, Supplement Series
Issue number2
StatePublished - Apr 2001


  • Gamma rays: observations
  • Pulsars: general
  • Stars: Wolf-Rayet
  • Supernova remnants
  • X-rays

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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