Counterparts to the Nuclear Bulge X-ray source population

TL;DR

This study matches Chandra X-ray sources in the Nuclear Bulge with near-infrared counterparts, revealing properties that distinguish foreground stars from Nuclear Bulge sources, despite high crowding.

Contribution

First attempt to match X-ray sources with near-infrared counterparts in the crowded Nuclear Bulge region, providing insights into their nature.

Findings

~50% of X-ray sources have candidate infrared counterparts.

J-band detections tend to be foreground sources.

H and K-band only detections are likely Nuclear Bulge sources.

Abstract

We present an initial matching of the source positions of the Chandra Nuclear Bulge X-ray sources to the new UKIDSS-GPS near-infrared survey of the Nuclear Bulge. This task is made difficult by the extremely crowded nature of the region, despite this, we find candidate counterparts to ~50% of the X-ray sources. We show that detection in the J-band for a candidate counterpart to an X-ray source preferentially selects those candidate counterparts in the foreground whereas candidate counterparts with only detections in the H and K-bands are more likely to be Nuclear Bulge sources. We discuss the planned follow-up for these candidate counterparts.