HUBBLE SPACE TELESCOPE IMAGING

OF THE CENTRAL 1 Kpc OF M81

ABSTRACT

M81 is the closest example of a galaxy that exhibits both LINER and Seyfert 1 characteristics. New, post repair (Cycle 5), Hubble Space Telescope imaging observations of the central kpc of M81 are presented, specifically, WFPC2 Ha and continuum images, a WFPC2 UV continuum (1500 Ang) image, and a V band FOC image. The continuum image shows a number of sinuous dust lanes that wind into the nucleus of M81. The Ha image reveals a small, ~ 7 arc sec (120 pc), bright, elliptical region of emission that appears to be a nuclear disk. The center of the disk-like structure is offset by less than 0.6 arc sec (10 pc) from the bright unresolved nucleus. The WFPC2 UV image shows that the disk is not ionized by massive stars. The highest angular resolution observations, obtained with the FOC, allow an upper limit of 0.04 arc sec (0.7 pc) to be placed on the size of the nucleus in the V band. The FOC image also shows that there are no stars, star clusters or additional nuclei visible within the centraol 4 x 4 arc sec region of M81 that are brighter than the galaxy background light.

More details appear in the Astrophysical JournalLetters, Devereux et al., 1997, 481, L71

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