2004/05/31 by D. P. Marrone, Daniel P. Marrone, James Battat +19 · 1 citation
Chemistry · Physics and Astronomy · #Astrophysics #Astrophysics and Star Formation Studies #Bar (unit) #Geometry #Line (geometry) #Meteorology #Molecular Spectroscopy and Structure #Observatory #Optics #Outflow #Physics #Resolution (logic) #Spectroscopy and Laser Applications #Telescope #Terahertz radiation #astro-ph
paper · pdf · doi:10.1086/422831
published as Astrophys.J. 612 (2004) 940-945 · Minor changes to references, text to match ApJ version
arxiv created 2004/09/06 · openalex publication_date 2004/09/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The distribution of 12 C 16 O J = 9 → 8 (1.037 THz) emission has been mapped in OMC-1 at 35 points with 84'' resolution. This is the first map of this source in this transition and only the second velocity-resolved ground-based observation of a line in the THz frequency band. There is emission present at all points in the map, a region roughly 4' × 6' in size, with peak antenna temperature dropping only near the edges. Away from the Orion KL outflow, the velocity structure suggests that most of the emission comes from the OMC-1 photon-dominated region, with a typical line width of 3-6 km s -1 . Large velocity gradient modeling of the emission in J = 9 → 8 and six lower transitions suggests that the lines originate in regions with temperatures around 120 K and densities of at least 10 3.5 cm -3 near θ 1 C Ori and at the Orion bar, and from 70 K gas at around 10 4 cm -3 southeast and west of the bar. These observations are among the first made with the 0.8 m Smithsonian Astrophysical Observatory Receiver Lab Telescope, a new instrument designed to observe at frequencies above 1 THz from an extremely high and dry site in northern Chile.