CXOGBS J173620.2-293338: A candidate symbiotic X-ray binary associated with a bulge carbon star
- Department of Physics and Astronomy, Louisiana State University, 202 Nicholson Hall, Tower Drive, Baton Rouge, LA 70803 (United States)
- SRON, Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA, Utrecht (Netherlands)
- Physics Department, 4-183 CCIS, University of Alberta, Edmonton AB, T6G 2E1 (Canada)
- Department of Physics, Texas Tech University, Box 41051, Lubbock, TX 79409-1051 (United States)
- I. M. Systems Group, Kensington, MD 20895 (United States)
- School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom)
- Astronomy and Astrophysics, Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom)
- Department of Astrophysics, IMAPP, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ, Nijmegen (Netherlands)
The Galactic Bulge Survey (GBS) is a wide but shallow X-ray survey of regions above and below the Plane in the Galactic Bulge. It was performed using the Chandra X-ray Observatory's ACIS camera. The survey is primarily designed to find and classify low luminosity X-ray binaries. The combination of the X-ray depth of the survey and the accessibility of optical and infrared counterparts makes this survey ideally suited to identification of new symbiotic X-ray binaries (SyXBs) in the Bulge. We consider the specific case of the X-ray source CXOGBS J173620.2-293338. It is coincident to within 1 arcsec with a very red star, showing a carbon star spectrum and irregular variability in the Optical Gravitational Lensing Experiment data. We classify the star as a late C-R type carbon star based on its spectral features, photometric properties, and variability characteristics, although a low-luminosity C-N type cannot be ruled out. The brightness of the star implies it is located in the Bulge, and its photometric properties are overall consistent with the Bulge carbon star population. Given the rarity of carbon stars in the Bulge, we estimate the probability of such a close chance alignment of any GBS source with a carbon star to be ≲ 10{sup –3}, suggesting that this is likely to be a real match. If the X-ray source is indeed associated with the carbon star, then the X-ray luminosity is around 9 × 10{sup 32} erg s{sup –1}. Its characteristics are consistent with a low luminosity SyXB, or possibly a low accretion rate white dwarf symbiotic.
- OSTI ID:
- 22348368
- Journal Information:
- Astrophysical Journal, Vol. 780, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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