Two Rapidly Variable Galactic X-ray Transients Observed with Chandra, XMM-Newton, and Suzaku
Abstract
We have identified two moderately bright, rapidly variable transients in new and archival X-ray data near the Galactic center. Both objects show strong, flaring variability on timescales of tens to thousands of seconds, evidence of NH variability, and hard spectra. XMMU J174445.5-295044 is seen at 2-10 keV fluxes of 3 × 10-11 to <10-12 erg cm-2 s-1, with NH at or above 5 × 1022 cm-2, by XMM-Newton, Chandra, and Suzaku. A likely Two Micron All Sky Survey (2MASS) counterpart with KS = 10.2 shows colors indicative of a late-type star. CXOU J174042.0-280724 is a likely counterpart to the fast hard transient IGR J17407-2808. Chandra observations find FX (2-10 keV) ~10-12 erg cm-2 s-1, with large NH variations (from 2 × 1022 to >2 × 1023 cm-2). No 2MASS counterpart is visible, to KS >13. XMMU J174445.5-295044 seems likely to be a new symbiotic star or symbiotic X-ray binary, while CXOU J174042.0-280724 is more mysterious, likely an unusual low-mass X-ray binary.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 2009
- DOI:
- 10.1088/0004-637X/701/2/1627
- arXiv:
- arXiv:0906.4743
- Bibcode:
- 2009ApJ...701.1627H
- Keywords:
-
- stars: neutron;
- X-rays: binaries;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 9 pages, 13 figures (5 color), ApJ in press