A&A 466, 949-968 (2007)
DOI: 10.1051/0004-6361:20054304

Observations of spatial and velocity structure in the Orion molecular cloud

H. D. Nissen¹, M. Gustafsson¹, J. L. Lemaire², Y. Clénet³, D. Rouan³, and D. Field<sup>1

1</sup>  Department of Physics and Astronomy, University of Aarhus, 8000 Aarhus C, Denmark
    e-mail: dfield@phys.au.dk
²  Observatoire de Paris and Université de Cergy-Pontoise, LERMA and UMR 8112 du CNRS, 92195 Meudon, France
³  Observatoire de Paris-Meudon, LESIA, 92195 Meudon Principal Cedex, France

(Received 5 October 2005 / Accepted 15 December 2006)

Abstract
Observations are reported of H₂ IR emission in the S(1) v=1-0 line at 2.121 m in the Orion Molecular Cloud, OMC1, using the GriF instrument on the Canada-France-Hawaii Telescope. GriF uses a combination of adaptive optics and Fabry-Perot interferometry, yielding a spatial resolution of 0.15´´ to 0.18´´ and velocity discrimination as high as 1 km s^-1. 193 bright H₂ emission regions can be identified in OMC1. The general characteristics of these features are described in terms of radial velocities, brightness and spatial displacement of maxima of velocity and brightness, the latter to yield the orientation of flows in the plane of the sky. Strong spatial correlation between velocity and bright H₂ emission is found and serves to identify many features as shocks. Important results are: (i) velocities of the excited gas illustrate the presence of a zone to the south of BN-IRc2 and Peak 1, and the west of Peak 2, where there is a powerful blue-shifted outflow with an average velocity of -18 km s^-1. This is shown to be the NIR counterpart of an outflow previously identified in the radio, originating from either source I or source n. (ii) There is a band of weak radial velocity features (<5 km s^-1) in Peak 1. (iii) A small proportion of the flows may represent sites of low mass star formation and one region shows evidence of multiple flows which may indicate multiple low mass star formation within OMC1.

Key words: ISM: jets and outflows -- ISM: structure -- stars: formation -- stars: circumstellar matter -- ISM: kinematics and dynamics -- ISM: molecules

© ESO 2007

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.