TheChandraDust-scattering Halo of Galactic Center Transient Swift J174540.7–290015

L. R. Corrales, B. Mon, D. Haggard, F. K. Baganoff, G. Garmire, N. Degenaar, M. Reynolds
2017 Astrophysical Journal  
We report the detection of a dust scattering halo around a recently discovered X-ray transient, Swift J174540.7-290015, which in early February of 2016 underwent one of the brightest outbursts (F_X ~ 5e-10 erg/cm^2/s) observed from a compact object in the Galactic Center field. We analyze four Chandra images that were taken as follow-up observations to Swift discoveries of new Galactic Center transients. After adjusting our spectral extraction for the effects of detector pileup, we construct a
more » ... up, we construct a point spread function for each observation and compare it to the GC field before the outburst. We find residual surface brightness around Swift J174540.7-290015, which has a shape and temporal evolution consistent with the behavior expected from X-rays scattered by foreground dust. We examine the spectral properties of the source, which shows evidence that the object transitioned from a soft to hard spectral state as it faded below L_X ~ 1e36 erg/s. This behavior is consistent with the hypothesis that the object is a low mass X-ray binary in the Galactic Center.
doi:10.3847/1538-4357/aa68dd fatcat:uskkgoqi45fkhdp5ttl3ks3wza