2001/03/26 by Yohko Tsuboi, Katsuji Koyama, Kenji Hamaguchi +5 · 6 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Astrophysics and Star Formation Studies #astro-ph
paper · pdf · doi:10.1086/321392
9 pages, To be appeared in ApJ v554 n2 Jun 20, 2001 issue, related press release is available at http://science.psu.edu/alert/Tsuboi11-2000.htm, Figure 1 and figure 2 with the best resolution is available at ftp.astro.psu.edu/pub/tsuboi/OMC/010205/
arxiv created 2001/03/26 · openalex publication_date 2001/06/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
We have observed the Orion Molecular Clouds 2 and 3 (OMC-2 and OMC-3) with the Chandra X-Ray Observatory ( CXO ). The northern part of OMC-3 is found to be particularly rich in new X-ray features; four hard X-ray sources are located in and along the filament of cloud cores. Two sources coincide positionally with the submillimeter-millimeter dust condensations of MMS 2 and 3 or an outflow radio source VLA 1, which are in a very early phase of star formation. The X-ray spectra of these sources show an absorption column of (1-3) × 10 23 H cm -2 . Assuming a moderate temperature plasma, the X-ray luminosity in the 0.5-10 keV band is estimated to be ~10 30 ergs s -1 at a distance of 450 pc. From the large absorption, positional coincidence, and moderate luminosity, we infer that the hard X-rays are coming from very young stellar objects embedded in the molecular cloud cores.We found another hard X-ray source near the edge of the dust filament. The extremely high absorption of 3 × 10 23 H cm -2 indicates that the source must be surrounded by dense gas, suggesting that it is either a young stellar object in an early accretion phase or a Type II AGN (e.g., a Seyfert 2), although no counterpart is found at any other wavelength. In contrast to the hard X-ray sources, soft X-ray sources are found spread around the dust filaments, most of which are identified with IR sources in the T Tauri phase.