Discovery of a hard X-ray source, SAX J0635 + 0533, in the error box of the gamma-ray source 2EG 0635 + 0521

Philip Kaaret, Santina Piraino, Jules Halpern, Michael Eracleous

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

We have discovered an X-ray source, SAX J0635 + 0533, with a hard spectrum within the error box of the GeV gamma-ray source in Monoceros, 2EG J0635 + 0521. The unabsorbed flux from the source is 1.2 × 10-11 ergs cm-2 s-1 in the 2-10 keV band. The X-ray spectrum is consistent with a simple power-law model with absorption. The photon index is 1.50 ± 0.08, and we detect emission out to 40 keV. Optical observations identify a counterpart with a V magnitude of 12.8. The counterpart has broad emission lines and the colors of an early B-type star. If the identification of the X-ray/optical source with the gamma-ray source is correct, then the source would be a gamma-ray-emitting X-ray binary.

Original languageEnglish (US)
Pages (from-to)197-202
Number of pages6
JournalAstrophysical Journal
Volume523
Issue number1 PART 1
DOIs
StatePublished - Sep 20 1999

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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