Search for the optical and infrared counterpart of GRS 1758-258

TL;DR

This study conducted a deep search for optical and infrared counterparts of GRS 1758-258, identifying two potential binary companions with further spectroscopic confirmation needed.

Contribution

The paper reports the identification of two candidate counterparts for GRS 1758-258 based on astrometry and photometry, highlighting the need for further spectroscopic follow-up.

Findings

Two candidate counterparts identified within 1" of the radio position.

One candidate consistent with a K-type giant star.

Another candidate consistent with an F-type main sequence star.

Abstract

We report the results of a deep search for the optical and near infrared counterpart of the microquasar source GRS1758-258. At least two possible candidate counterparts of the binary star companion have been recognized on the basis of astrometric coincidence to within 1". Our photometric study shows that the brightest of them would be consistent with a K-type giant star, while the weakest one would be a main sequence F companion. Follow up spectroscopic observations in the near infrared H and K-bands have failed so far to provide evidence for emission lines that may support an unambiguous identification. However, the proximity of these two sources to the sub-arcsec VLA radio position of GRS 1758-258 makes them deserving further attention in the future.