AROUND 200 NEW X-RAY BINARY IDs FROM 13 YR OF CHANDRA OBSERVATIONS OF THE M31 CENTER
Author(s)Barnard, R.; Garcia, M. R.; Primini, F.; Li, Z.; Murray, Stephen S.; Baganoff, Frederick K; ... Show more Show less
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We have created 0.3-10 keV, 13 yr, unabsorbed luminosity lightcurves for 528 X-ray sources in the central 20' of M31. We have 174 Chandra observations spaced at ~1 month intervals due to our transient monitoring program, deeper observations of the M31 nucleus, and some public data from other surveys. We created 0.5-4.5 keV structure functions (SFs) for each source for comparison with the ensemble SF of active galactic nuclei (AGN). We find 220 X-ray sources with luminosities [> over ~]10[superscript 35] erg s[superscript –1] that have SFs with significantly more variability than the ensemble AGN SF, and which are likely X-ray binaries (XBs). A further 30 X-ray sources were identified as XBs using other methods. We therefore have 250 probable XBs in total, including ~200 new identifications. This result represents great progress over the ~50 XBs and ~40 XB candidates previously identified out of the ~2000 X-ray sources within the D [subscript 25] region of M31; it also demonstrates the power of SF analysis for identifying XBs in external galaxies. We also identify a new transient black hole candidate, associated with the M31 globular cluster B128.
DepartmentMIT Kavli Institute for Astrophysics and Space Research
The Astrophysical Journal
Barnard, R., M. R. Garcia, F. Primini, Z. Li, F. K. Baganoff, and S. S. Murray. “AROUND 200 NEW X-RAY BINARY IDs FROM 13 YR OF CHANDRA OBSERVATIONS OF THE M31 CENTER.” The Astrophysical Journal 780, no. 1 (December 13, 2013): 83. © 2014 The American Astronomical Society
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