Mid-IR forcast/SOFIA observations of M82

T. Nikola, Cornell University
T. L. Herter, Cornell University
W. D. Vacca, Universities Space Research Association
J. D. Adams, Cornell University
J. M. De Buizer, Universities Space Research Association
G. E. Gull, Cornell University
C. P. Henderson, Cornell University
L. D. Keller, Ithaca College
M. R. Morris, University of California, Los Angeles
J. Schoenwald, Cornell University
G. Stacey, Cornell University
A. Tielens, Leiden Observatory Research Institute

Abstract

We present 75″ × 75″ size maps of M82 at 6.4 μm, 6.6 μm, 7.7 μm, 31.5 μm, and 37.1 μm with a resolution of ∼4″ that we have obtained with the mid-IR camera FORCAST on SOFIA. We find strong emission from the inner 60″ (∼1 kpc) along the major axis, with the main peak 5″ west-southwest of the nucleus and a secondary peak 4″ east-northeast of the nucleus. The detailed morphology of the emission differs among the bands, which is likely due to different dust components dominating the continuum emission at short mid-IR wavelengths and long mid-IR wavelengths. We include Spitzer-IRS and Herschel/PACS 70 μm data to fit spectral energy distribution templates at both emission peaks. The best-fitting templates have extinctions of A = 18 and A = 9 toward the main and secondary emission peak and we estimated a color temperature of 68 K at both peaks from the 31 μm and 37 μm measurement. At the emission peaks the estimated dust masses are on the order of 10 M . © 2012. The American Astronomical Society. All rights reserved. V V Ȯ 4