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).

Publication Date



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.ISSN:1432-0746 Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

Document Type


Department, Program, or Center

Chester F. Carlson Center for Imaging Science (COS)


RIT – Main Campus