Identification of 23 accreting binaries in the galactic bulge survey

M. A.P. Torres, P. G. Jonker, C. T. Britt, C. B. Johnson, R. I. Hynes, S. Greiss, D. Steeghs, T. J. Maccarone, F. Özel, C. Bassa, G. Nelemans

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


We present the identification of optical counterparts to 23 GBS X-ray sources. All sources are classified as accreting binaries according to the emission-line characteristics inferred from medium-resolution spectroscopy. To distinguish accreting binaries from chromospherically active objects, we develop criteria based onHα and He I λλ5786, 6678 emission-line properties available in the literature. The spectroscopic properties and photometric variability of each object is discussed and a classification is given where possible. At least 12 of the 23 systems show an accretion-dominated optical spectrum and another 6 show stellar absorption features in addition to emission lines indicating that they are probably accreting binaries in quiescence or in a low accretion rate state. Two sources are confirmed to be eclipsing: CX207 and CX794. CX207 is likely a magnetic cataclysmic variable (CV), while CX794 is a nova-like CV in the period gap. Finally, the large broadening (2100 km s-1 FWHM) of the Hα emission lines in CX446 and CX1004 suggests that they are also high-inclination or even eclipsing systems. Whether the compact object is a white dwarf in an eclipsing CV, a neutron star or a black hole in a high-inclination low-mass X-ray binary remains to be established.

Original languageEnglish
Pages (from-to)365-386
Number of pages22
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - Apr 2014


  • Accretion
  • Accretion discs-black hole physics-techniques
  • Binaries
  • Close-stars
  • Neutron-X-rays
  • Radial velocities-binaries


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