Quiescent X-Ray/Optical Counterparts of the Black Hole Transient H 1705-250

Y.J. Yang, A.K.H. Kong, D.M. Russell, Fraser Lewis, R. Wijnands

Research output: Contribution to journalArticlepeer-review


We report the result of a new Chandra observation of the black hole X-ray transient H 1705−250 in quiescence. H 1705−250 was barely detected in the new ∼50 ks Chandra observation. With five detected counts, we estimate the source quiescent luminosity to be LX ∼ 9.1 × 1030 erg s−1 in the 0.5–10 keV band (adopting a distance of 8.6 kpc). This value is in line with the quiescent luminosities found among other black hole X-ray binaries with similar orbital periods. By using images taken with the Faulkes Telescope North, we derive a refined position of H 1705−250. We also present the long-term light curve of the optical counterpart from 2006 to 2012, and show evidence for variability in quiescence.
Original languageEnglish
Pages (from-to)2876-2880
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
Publication statusPublished - 12 Sept 2012


  • x-ray bindaries - black holes


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