Using Chandra Localizations and Gaia Distances and Proper Motions to Classify Hard X-ray Sources Discovered by INTEGRAL

TL;DR

This study uses Chandra X-ray localizations combined with Gaia data to classify ten hard X-ray sources from INTEGRAL, identifying several as Galactic objects like magnetic CVs and some as AGN, enhancing understanding of their nature.

Contribution

The paper introduces precise Chandra localizations and Gaia data integration to classify INTEGRAL-discovered X-ray sources, providing new insights into their Galactic or extragalactic origins.

Findings

Six sources are confidently identified with Chandra counterparts.

Most classified sources are Galactic, including magnetic CVs.

Some sources are likely AGN or highly variable.

Abstract

Here we report on X-ray observations of ten 17-60 keV sources discovered by the INTEGRAL satellite. The primary new information is sub-arcsecond positions obtained by the Chandra X-ray Observatory. In six cases (IGR J17040-4305, IGR J18017-3542, IGR J18112-2641, IGR J18434-0508, IGR J19504+3318, and IGR J20084+3221), a unique Chandra counterpart is identified with a high degree of certainty, and for five of these sources (all but J19504), Gaia distances or proper motions indicate that they are Galactic sources. For four of these, the most likely classifications are that the sources are magnetic Cataclysmic Variables (CVs). J20084 could be either a magnetic CV or a High Mass X-ray Binary. We classify the sixth source (J19504) as a likely Active Galactic Nucleus (AGN). In addition, we find likely Chandra counterparts to IGR J18010-3045 and IGR J19577+3339, and the latter is a bright radio source and probable AGN. The other two sources, IGR J12529-6351 and IGR J18013-3222 do not have likely Chandra counterparts, indicating that they are transient, highly variable, or highly absorbed.