The Chandra Small Magellanic Cloud Wing Survey - the search for X-ray Binaries

TL;DR

This study used Chandra X-ray observations to identify and classify 523 sources in the SMC Wing, revealing a diverse population including pulsars, HMXB candidates, stars, and AGNs, with implications for understanding the region's X-ray source distribution.

Contribution

It presents the first comprehensive X-ray survey of the SMC Wing, combining multi-wavelength data to classify sources and compare their abundance with the SMC Bar.

Findings

Detected 523 X-ray sources in the SMC Wing.

Classified 265 sources using X-ray and optical data.

Found a lower number of HMXBs in the Wing compared to the SMC Bar.

Abstract

We have detected 523 sources in a survey of the Small Magellanic Cloud (SMC) Wing with Chandra. By cross-correlating the X-ray data with optical and near-infrared catalogues we have found 300 matches. Using a technique that combines X-ray colours and X-ray to optical flux ratios we have been able to assign preliminary classifications to 265 of the objects. Our identifications include four pulsars, one high-mass X-ray binary (HMXB) candidate, 34 stars and 185 active galactic nuclei (AGNs). In addition, we have classified 32 sources as 'hard' AGNs which are likely absorbed by local gas and dust, and nine 'soft' AGNs whose nature is still unclear. Considering the abundance of HMXBs discovered so far in the Bar of the SMC the number that we have detected in the Wing is low.