High Resolution Continuum and Br$\gamma$ Imaging Observations of M82
Session 31 -- Star-Forming Galaxies
Display presentation, Tuesday, 9:30-6:30, Heller Lounge Room

## [31.14] High Resolution Continuum and Br$\gamma$ Imaging Observations of M82

J. E. Larkin (Palomar Observatory, Caltech), J. R. Graham (U. C. Berkeley), K. Matthews, B. T. Soifer (Palomar Observatory, Caltech), S. Beckwith, T. M. Herbst (Max-Planck-Institut f\"ur Astronomie), A. C. Quillen (Caltech)

We describe high angular resolution ($\sim$0.6''), broad band imaging at 1.2~$\mu$m (J band), 1.6~$\mu$m (H band), 2.2~$\mu$m (K band), and 3.7~$\mu$m (L' band) of the central 110''~x~21'' (1.65~kpc~x~0.32~kpc) of the nearby starburst galaxy M82. We also present spectral imaging with 90~km~$s^{-1}$ resolution in the Br$\gamma$ (2.17~$\mu$m) hydrogen recombination line covering the central 16''~x~16'' (240~pc~x~240~pc) of this edge-on, disk galaxy.

The broad band mosaics reveal two plateaus of emission indicative of an inner disk of stars and perhaps a larger bar structure. Color maps reveal an extinction ridge running along the central kiloparsec which is strongest at the nucleus and on the western side. The dust emission is more symmetric, suggesting that a dust lane is in front of the stellar population to the west of the nucleus, and behind the stars to the east; this is again suggestive of a stellar bar with leading dust lanes. Channel maps and a position-velocity image of the Br$\gamma$ emission reveal two lobes and are consistent with the interpretation that the ionized gas, and hence, the young massive stars are distributed in a toroid of HII regions surrounding the nucleus.