Issue |
A&A
Volume 412, Number 3, December IV 2003
|
|
---|---|---|
Page(s) | 727 - 734 | |
Section | Galactic structure, stellar clusters, and populations | |
DOI | https://doi.org/10.1051/0004-6361:20031276 | |
Published online | 08 December 2003 |
H2 excitation imaging of the Orion Molecular Cloud*
1
Department of Physics and Astronomy, University of Aarhus, 8000 Aarhus C, Denmark
2
Observatoire de Paris-Meudon, LERMA and UMR 8112 of the CNRS, 92195 Meudon Principal Cedex, France
3
Université de Cergy-Pontoise, LERMA and UMR 8112 of the CNRS, 95806 Cergy Cedex, France
4
Institut d'Astrophysique Spatiale, Université Paris XI, 91405 Orsay Cedex, France
Corresponding author: D. Field, dfield@phys.au.dk
Received:
30
January
2003
Accepted:
11
August
2003
Observations are reported of IR emission in H2, around
2 μm in the K-band, obtained with the ESO 3.6 m telescope
using the ADONIS adaptive optics system. Data cover a region of the
Orion Molecular Cloud north of the Trapezium stars and SW of the
Becklin-Neugebauer object. Excellent seeing yielded diffraction
limited images in the S(1) line at 2.247 μm. Excitation
temperature images were created by combining these data with similar
data for H2 emission in the
S(1) line reported earlier
(Vannier et al. [CITE]). Shock models are used to estimate
densities in emitting clumps of material. In local zones with high
excitation temperatures, post-shock densities are found to be as
high as several times 108 cm-3, an order of magnitude denser
than our previous estimates. We propose that the
nature of these zones is dictated by the combined activity of
shocks, which create dense structures, and the powerful radiation
field of θ1C Ori which photoevaporates the boundaries of
these structures.
Key words: ISM: individual objects: OMC1 / ISM: kinematics and dynamics / ISM: molecules / shock waves / ISM: lines and bands
© ESO, 2003
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