X-Rays from HH210 in the Orion Nebula

Nicolas Grosso, Université Joseph-Fourier
Eric D. Feigelson, The Pennsylvania State University
Konstantin Getman, The Pennsylvania State University
Joel H. Kastner, Rochester Institute of Technology
J. Bally, University of Colorado, Boulder
M. J. McCaughrean, University of Exeter

This is the pre-print of an article published by EDP Sciences. The final, published version is available here: https://doi.org/10.1051/0004-6361:200600004

Reproduced with permission from Astronomy & Astrophyics, © 2006 ESO

Also archived in: arXiv: astro-ph/0601508 v1 23 Jan 2006

We thanks an anonymous referee for useful comments which improved the paper. COUP is supported by the Chandra Guest Observer grant SAO GO3-4009A (E. Feigelson, PI). Further support was provided by the Chandra ACIS Team contract SV4-74018.

Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.


We report the detection during the Chandra Orion Ultradeep Project (COUP) of two soft, constant, and faint X-ray sources associated with the Herbig-Haro object HH210. HH210 is located at the tip of the NNE finger of the emission line system bursting out of the BN-KL complex, northwest of the Trapezium cluster in the OMC-1 molecular cloud. Using a recent H-alpha image obtained with the ACS imager on board HST, and taking into account the known proper motions of HH210 emission knots, we show that the position of the brightest X-ray source, COUP 703, coincides with the emission knot 154-040a of HH210, which is the emission knot of HH210 having the highest tangential velocity (425 kms^−1). The second X-ray source, COUP 704, is located on the complicated emission tail of HH210 close to an emission line filament and has no obvious optical/infrared counterpart. Spectral fitting indicates for both sources a plasma temperature of ~0.8MK and absorption-corrected X-ray luminosities of about 10^30 erg s^−1 (0.5–2.0 keV). These X-ray sources are well explained by a model invoking a fast moving, radiative bow shock in a neutral medium with a density of ~12000 cm^−3. The X-ray detection of COUP 704 therefore reveals, in the complicated HH210 region, an energetic shock not yet identified at other wavelengths (Refer to PDF file for exact formulas).