The 2013 outburst of a transient very faint X-ray binary, 23 arcsec from Sgr A

E. W. Koch*, A. Bahramian, C. O. Heinke, K. Mori, N. Rea, N. Degenaar, D. Haggard, R. Wijnands, G. Ponti, J. M. Miller, F. Yusef-Zadeh, F. Dufour, W. D. Cotton, F. K. Baganoff, M. T. Reynolds

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


We report observations using the Swift/XRT, NuSTAR, and Chandra X-ray telescopes of the transient X-ray source CXOGC J174540.0-290005 during its 2013 outburst. Due to its location in the field of multiple observing campaigns targeting Sgr A*, this is one of the best-studied outbursts of a very faint X-ray binary (VFXB; peak LX < 1036 erg s-1) yet recorded, with detections in 173 ks of X-ray observations over 50 d. VFXBs are of particular interest, due to their unusually low outburst luminosities and time-averaged mass transfer rates, which are hard to explain within standard accretion physics and binary evolution. The 2013 outburst of CXOGC J174540.0-290005 peaked at LX(2-10 keV) = 5.0 × 1035 erg s-1, and all data above 1034 erg s-1 were well fitted by an absorbed power law of photon index ∼1.7, extending from 2 keV out to ≳70 keV. We discuss the implications of these observations for the accretion state of CXOGC J174540.0-290005.

Original languageEnglish (US)
Pages (from-to)372-381
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - Jun 2014


  • Accretion, accretion discs
  • X-rays: binaries
  • X-rays: individual: CXOGCJ174540.0-290005

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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