Deep infrared and optical studies of the fields of three proposed TZ.O remnants

Deep infrared and optical images are presented of three proposed remnants of Thorne–Z^.ytkow objects (TZ^.Os). In particular, the infrared data go several infrared magnitudes deeper than previous observations, and in at least one case reveal the existence of weak objects within the error circles. It is argued, however, that none of the objects is likely to be the binary companion to the X-ray source in that region. These data present severe limits on any possible star or residual envelope at the distances of the respective X-ray objects.