A&A 412, 727-734 (2003)
DOI: 10.1051/0004-6361:20031276

H excitation imaging of the Orion Molecular Cloud

L. E. Kristensen¹, M. Gustafsson¹, D. Field¹, G. Callejo^{2, 3}, J. L. Lemaire^{2, 3}, L. Vannier² and G. Pineau des Forêts<sup>4

1</sup>  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

(Received 30 January 2003 / Accepted 11 August 2003)

Abstract
Observations are reported of IR emission in H ₂, around 2  m 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 v=2-1 S(1) line at 2.247  m. Excitation temperature images were created by combining these data with similar data for H ₂ emission in the v=1-0 S(1) line reported earlier (Vannier et al. 2001). 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 10 ⁸ 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 ¹C 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

Offprint request: D. Field, dfield@phys.au.dk

SIMBAD Objects

© ESO 2003

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

• If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
• You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
• You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.