We present phase-resolved spectroscopy and photometry of a source discovered with the Chandra Galactic Bulge Survey (GBS), CXOGBS J174444.7-260330 (aka CX93 and CX153 in the previously published GBS list). We find two possible values for the orbital period P, differing from each other by ˜13 s. The most likely solution is P = 5.690 14(6) h. The optical lightcurves show ellipsoidal modulations, whose modelling provides an inclination of 32±1° for the most likely P. The spectra are dominated by a K5 V companion star (the disc veiling is ≲5 per cent). Broad and structured emission from the Balmer lines is also detected, as well as fainter emission from He i. From the absorption lines we measure K2 = 117 ± 8 km s- 1 and v sin i = 69 ± 7 km s- 1. By solving the system mass function we find M1 = 0.8 ± 0.2 M⊙ for the favoured P and i, consistent with a white dwarf accretor, and M2 = 0.6 ± 0.2 M⊙. We estimate a distance in the range 400-700 pc. Although in a low accretion state, both spectros
|Journal||Monthly Notices of the Royal Astronomical Society|
|State||Published - Feb 2013|
Ratti, E. M., Grunsven, T. F. J. V., Jonker, P. G., Britt, C. T., Hynes, R. I., Steeghs, D., Greiss, S., Torres, M. A. P., Maccarone, T., & Authors, S. O. (2013). CXOGBS J174444.7-260330: a new long orbital period cataclysmic variable in a low state. Monthly Notices of the Royal Astronomical Society, 3543.