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arXiv · 1902.08635

Multiwavelength survey of X-ray sources in the Sculptor Dwarf Spheroidal Galaxy

R. M. Arnason·P. Barmby·A. Bahramian·T. J. Maccarone·S. E. Zepf
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Abstract

We present an unprecedented, deep study of the primordial low-mass X-ray binary population in an isolated, lower-metallicity environment. We perform followup observations of previously-identified X-ray binary candidates in the Sculptor Dwarf Galaxy by combining a second Chandra observation with Spitzer and Gemini photometry, as well as Gemini spectroscopy of selected targets. Of the original nine bright X-ray sources identified, we are able to classify all but one as quasars, active galactic nuclei, or background galaxies. We further discover four new X-ray sources in the second-epoch Chandra observation. Three of these new sources are background sources and one is a foreground flaring star. We have found that Sculptor is effectively devoid of X-ray sources above a few 1e34 erg/s. If Sculptor is able to retain primordial binaries at a similar rate to globular clusters, this implies that bright X-ray binaries observed in globular clusters in the present epoch are all formed dynamically.

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R. M. Arnason, P. Barmby, A. Bahramian, T. J. Maccarone, S. E. Zepf. 2019-02-22. Multiwavelength survey of X-ray sources in the Sculptor Dwarf Spheroidal Galaxy. https://doi.org/10.1093/mnras%2Fstz554

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