CXOGBS J174954.5-294335: A new deeply eclipsing intermediate polar

Christopher B. Johnson, M. A.P. Torres, R. I. Hynes, P. G. Jonker, C. Heinke, T. Maccarone, C. T. Britt, D. Steeghs, T. Wevers, J. Wu

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Abstract

We present the results of a photometric and spectroscopic analysis of the Galactic Bulge Survey X-ray source CXOGBS J174954.5-294335 (hereafter, referred to as CX19). CX19 is a long period, eclipsing intermediate polar-type cataclysmic variable with broad, singlepeaked Balmer and Paschen emission lines along with He II λ4686 and Bowen blend emission features. With coverage of one full and two partial eclipses and archival photometry, we determine the ephemeris for CX19 to beHJD(eclipse)=2455691.8581(5)+0.358704(2)×N. We also recovered the white dwarf spin period of Pspin = 503.32(3) s that gives a Pspin/Porb = 0.016(6), comparable to several confirmed, long-period intermediate polars. CX19 also shows a clear X-ray eclipse in the 0.3-8.0 keV range observed with Chandra. Two optical outbursts were observed lasting between 6 and 8 h (lower limits) reaching ~1.3 mag in amplitude. The outbursts, both in duration and magnitude, the accretion disc-dominated spectra and hard X-ray emission are reminiscent of the intermediate polar V1223 Sgr sharing many of the same characteristics. If we assume amain-sequence companion, we estimate the donor to be an early G-type star and find a minimum distance of d ≈ 2.1 kpc and a 0.5-10.0 keV X-ray luminosity upper limit of 2.0 × 1033 erg s-1. Such an X-ray luminosity is consistent with a white dwarf accretor in a magnetic cataclysmic variable system. To date, CX19 is only the second deeply eclipsing intermediate polar with X-ray eclipses and the first that is optically accessible.

Original languageEnglish
Pages (from-to)129-137
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Volume466
Issue number1
DOIs
StatePublished - Jan 1 2017

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Keywords

  • Binaries: eclipsing
  • Cataclysmic variables
  • Galaxy: bulge
  • Novae
  • Stars: magnetic field
  • White dwarfs
  • X-rays: binaries

Cite this

Johnson, C. B., Torres, M. A. P., Hynes, R. I., Jonker, P. G., Heinke, C., Maccarone, T., Britt, C. T., Steeghs, D., Wevers, T., & Wu, J. (2017). CXOGBS J174954.5-294335: A new deeply eclipsing intermediate polar. Monthly Notices of the Royal Astronomical Society, 466(1), 129-137. https://doi.org/10.1093/mnras/stw3063