The Chandra Dust Scattering Halo of Galactic Center transient Swift J174540.7-290015

Abstract

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 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.

Accepted for publication in ApJ

References in corpus (8)

• An Improved Distance and Mass Estimate for Sgr A* from a Multistar Orbit Analysis
• A Catalog of X-ray Point Sources from Two Megaseconds of Chandra Observations of the Galactic Center
• The dust scattering component of X-ray extinction: Effects on continuum fitting and high-resolution absorption edge structure
• The Impact of Accurate Extinction Measurements for X-ray Spectral Models
• A Joint Chandra and Swift View of the 2015 X-Ray Dust Scattering Echo of V404 Cygni
• Towards Self-Consistent Modelling of the Sgr A* Accretion Flow: Linking Theory and Observation
• X-ray Dust Scattering at Small Angles: The Complete Halo around GX13+1
• Swift J174540.7-290015: a new accreting binary in the Galactic Center

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• Ray-tracing simulations and spectral models of X-ray radiation in dusty media
• NuSTAR and Chandra observations of new X-ray transients in the central parsec of the Galaxy
• Continuation of the X-ray monitoring of Sgr A*: the increase in bright flaring rate confirmed
• eROSITA X-ray Analysis of the PeVatron Candidate Westerlund 1
• Iron K-alpha echoes from the circumnuclear disk orbiting Sgr A*