1E 2259+586

G. G. Fahiman, P. C. Gregory, P. Hickson and H. B. Richer, University of British Columbia, report an improved position, obtained with the high-resolution detector of the Einstein Observatory, for the 286.6-MHz pulsar 1E 2259+586: R. A. 22h59m02s.63, Decl. +58o36'37".6 (equinox 1950.0; uncertainty +/- 5"). Observations with the U.B.C. intensified CCD detector on the Canada-France-Hawaii telescope reveal two faint optical candidates to magnitude B = 23 within 10" of the x-ray position. The coordinates (+/- 1") and magnitudes are: Candidate R. A. (1950) Decl. B A 22 59 02.81 +58 36 33.3 22.0 B 22 59 02.12 +58 36 42.4 21.2 J. Middleditch, Los Alamos National Laboratory; and C. Pennypacker and S. Burns, Lawrence Berkeley Laboratory, report that a 1-hr time-resolved infrared observation of Candidate A with a 5".7 aperture on the NASA 3.0-m infrared telescope shows, in the 0.9-2.4- um band, periodic pulsations at 285.6 MHz with magnitude H ~ 17.5. The 1 MHz downshift of the infrared pulse frequency relative to the x-ray pulse frequency is consistent with reprocessing of the x-ray pulsation by a companion star in a close binary orbit.