X-Rays from HH210 in the Orion Nebula
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.
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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).