Three New Galactic Center X-ray Sources Identified with Near-Infrared Spectroscopy

TL;DR

This study used near-infrared spectroscopy to identify three new X-ray sources in the Galactic Center, including a Be HMXB, a symbiotic binary, and an O-type star, confirming their active nature.

Contribution

The paper reports the first spectroscopic identifications of a Be HMXB, a symbiotic X-ray binary, and an O-type star in the Galactic Center region.

Findings

Identification of three new X-ray sources with spectral evidence.

First spectroscopic confirmation of these classes in the GC.

Spectral characteristics support active binary classification.

Abstract

We have conducted a near-infrared spectroscopic survey of 47 candidate counterparts to X-ray sources discovered by the Chandra X-ray Observatory near the Galactic Center (GC). Though a significant number of these astrometric matches are likely to be spurious, we sought out spectral characteristics of active stars and interacting binaries, such as hot, massive spectral types or emission lines in order to corroborate the X-ray activity and certify the authenticity of the match. We present three new spectroscopic identifications, including a Be high mass X-ray binary (HMXB) or a gamma Cassiopeiae (Cas) system, a symbiotic X-ray binary and an O-type star of unknown luminosity class. The Be HMXB/gamma Cas system and the symbiotic X-ray binary are the first of their classes to be spectroscopically identified in the GC region.