R. Y. Shuping, Mark R. Morris, Terry L. Herter, Joseph D. Adams, G. E. Gull, J. Schoenwald, C. P. Henderson, E. E. Becklin, James M. De Buizer, William D. Vacca, Hans Zinnecker, S. Thomas Megeath
We present new mid-infrared images of the central region of the Orion Nebula
using the newly commissioned SOFIA airborne telescope and its 5 -- 40 micron
camera FORCAST. The 37.1 micron images represent the highest resolution
observations (<4") ever obtained of this region at these wavelengths. After
BN/KL (which is described in a separate letter in this issue), the dominant
source at all wavelengths except 37.1 micron is the Ney-Allen Nebula, a
crescent-shaped extended source associated with theta 1D. The morphology of the
Ney-Allen nebula in our images is consistent with the interpretation that it is
ambient dust swept up by the stellar wind from theta 1D, as suggested by Smith
et al. (2005). Our observations also reveal emission from two "proplyds"
(proto-planetary disks), and a few embedded young stellar objects (YSOs; IRc9,
and OMC1S IRS1, 2, and 10). The spectral energy distribution for IRc9 is
presented and fitted with standard YSO models from Robitaille et al. (2007) to
constrain the total luminosity, disk size, and envelope size. The diffuse,
nebular emission we observe at all FORCAST wavelengths is most likely from the
background photodissociation region (PDR) and shows structure that coincides
roughly with H_alpha and [N II] emission. We conclude that the spatial
variations in the diffuse emission are likely due to undulations in the surface
of the background PDR.
View original:
http://arxiv.org/abs/1202.4479
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