SEARCH FOR THE OPTICAL AND INFRARED COUNTERPART OF GRS-1758-258

We report the results of a deep search for the optical and near infrar ed counterpart of the microquasar source GRS 1758-258. At least two po ssible candidate counterparts of the binary star companion have been r ecognized on the basis of astrometric coincidence to within 1''. Our p hotometric study shows that the brightest of them would be consistent with a K-type giant star, while the weakest one would be a main sequen ce F companion. Follow up spectroscopic observations in the near infra red H and K-bands have failed so far to provide evidence for emission lines that may support an unambiguous identification. However, the pro ximity of these two sources to the sub-arcsec VLA radio position of GR S 1758-258 makes them deserving further attention in the future.