THE CONTINUING SEARCH FOR THE OPTICAL COUNTERPART OF THE ENIGMATIC X-RAY PULSAR 1E2259+586

We present a reanalysis of the Einstein X-ray images and new optical spectroscopy of the candidates for the X-ray pulsar 1E2259 + 586. Although we are not able to identify conclusively the optical counterpart, the very faint limit found for its brightness implies that the secondary star in a low-mass X-ray binary system cannot be brighter than a main-sequence K star. We identify faint diffuse knots of X-ray emission aligned with the pulsar in the Einstein HRI image, again raising the possibility of a jet, and strengthening the association of the pulsar with the supernova remnant. Further implications of our results are discussed.