Discovery of a high state AM CVn binary in the Galactic Bulge Survey

作者：Wevers T; Torres M A P; Jonker P G; Wetuski J D; Nelemans G; Steeghs D; Maccarone T J; Heinke C; Hynes R I; Udalski A; Kostrzewa Rutkowska Z; Groot P J; Gazer R; Szymanski M K; Britt C T; Wyrzykowski L; Poleski R

来源：Monthly Notices of the Royal Astronomical Society, 2016, 462(1): L106-L110.

DOI：10.1093/mnrasl/slw141

• accretion, accretion discs
• binaries: close
• stars: evolution
• white dwarfs
• X-rays: binaries
• CXOGBS J175107.6-294037

We report on the discovery of a hydrogen-deficient compact binary (CXOGBS J175107.6-294037) belonging to the AM CVn class in the Galactic Bulge Survey. Deep archival X-ray observations constrain the X-ray positional uncertainty of the source to 0.57 arcsec, and allow us to uniquely identify the optical and UV counterpart. Optical spectroscopic observations reveal the presence of broad, shallow He I absorption lines while no sign of hydrogen is present, consistent with a high state system. We present the optical light curve from Optical Gravitational Lensing Experiment monitoring, spanning 15 yr. It shows no evidence for outbursts; variability is present at the 0.2 mag level on time-scales ranging from hours to weeks. A modulation on a time-scale of years is also observed. A Lomb-Scargle analysis of the optical light curves shows two significant periodicities at 22.90 and 23.22 min. Although the physical interpretation is uncertain, such time-scales are in line with expectations for the orbital and superhump periods. We estimate the distance to the source to be between 0.5 and 1.1 kpc. Spectroscopic follow-up observations are required to establish the orbital period, and to determine whether this source can serve as a verification binary for the eLISA gravitational wave mission.

• 出版日期2016-10-11