HUBBLE-SPACE-TELESCOPE IMAGING OF THE CENTRAL 1 KILOPARSEC OF M81

M81 is the closest example of a galaxy that exhibits both LINER and Se yfert 1 characteristics. New, postrepair (cycle 5), Hubble Space Teles cope imaging observations of the central kpc of M81 are presented, spe cifically, WFPC2 H alpha and continuum images, a WFPC2 UV continuum (1 500 Angstrom) image, and a V-band faint object camera (FOC) image. The continuum image shows a number of sinuous dust lanes that wind into t he nucleus of M81. The H alpha image reveals a small, similar to 7 '' (120 pc), bright, elliptical region of emission that appears to be a n uclear disk. The center of the disklike structure is offset by less th an 0.6 '' (10 pc) from the bright unresolved nucleus. The WFPC2 UV ima ge shows that the disk is not ionized by massive stars. The highest an gular resolution observations, obtained with the FOC, allow an upper l imit of 0.04 '' (0.7 pc) to be placed on the size of the nucleus in th e V band. The FOC image also shows that there are no stars, star clust ers, or additional nuclei visible within the central 4 '' x 4 '' regio n of M81 that are brighter than the galaxy background light.