90 GHz AND 150 GHz OBSERVATIONS OF THE ORION M42 REGION. A SUBMILLIMETER TO RADIO ANALYSIS

Journal Article · Sun Nov 01 04:00:00 EST 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/705/1/226· OSTI ID:21378393

Dicker, S R; Korngut, P M; Devlin, M J ^[1]; Mason, B S; Cotton, W D ^[2]; Compiegne, M; Martin, P G ^[3]; Ade, P A. R; Tucker, C ^[4]; Benford, D J; Staguhn, J G ^[5]; Irwin, K D ^[6]; Maddalena, R J; McMullin, J P; Shepherd, D S ^[7]; Sievers, A ^[8]

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1. University of Pennsylvania, 209 S. 33rd St, Philadelphia, PA 19104 (United States)
2. National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States)
3. Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St George St, Toronto, ON M5S 3H8 (Canada)
4. Cardiff University, 5 The Parade, Cardiff, CF24 3YB (United Kingdom)
5. NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
6. National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305 (United States)
7. National Radio Astronomy Observatory, Green Bank, WV 24944 (United States)
8. IRAM, Avenida Divina Pastora, 7, Nucleo Central, E 18012 Granada (Spain)

We have used the new 90 GHz MUSTANG camera on the Robert C. Byrd Green Bank Telescope (GBT) to map the bright Huygens region of the star-forming region M42 with a resolution of 9'' and a sensitivity of 2.8 mJy beam{sup -1}. Ninety GHz is an interesting transition frequency, as MUSTANG detects both the free-free emission characteristic of the H II region created by the Trapezium stars, normally seen at lower frequencies, and thermal dust emission from the background OMC1 molecular cloud, normally mapped at higher frequencies. We also present similar data from the 150 GHz GISMO camera taken on the IRAM 30 m telescope. This map has 15'' resolution. By combining the MUSTANG data with 1.4, 8, and 21 GHz radio data from the VLA and GBT, we derive a new estimate of the emission measure averaged electron temperature of T{sub e} = 11376 +- 1050 K by an original method relating free-free emission intensities at optically thin and optically thick frequencies. Combining Infrared Space Observatory-long wavelength spectrometer (ISO-LWS) data with our data, we derive a new estimate of the dust temperature and spectral emissivity index within the 80'' ISO-LWS beam toward Orion KL/BN, T{sub d} = 42 +- 3 K and beta {sub d} = 1.3 +- 0.1. We show that both T{sub d} and beta {sub d} decrease when going from the H II region and excited OMC1 interface to the denser UV shielded part of OMC1 (Orion KL/BN, Orion S). With a model consisting of only free-free and thermal dust emission, we are able to fit data taken at frequencies from 1.5 GHz to 854 GHz (350 mum).

• OSTI ID: 21378393
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 705; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CAMERAS
DUSTS
ELECTRON TEMPERATURE
EMISSION
EMISSIVITY
FREQUENCY RANGE
GHZ RANGE
MAPS
MEASURING INSTRUMENTS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
SPECTROMETERS
STARS
SURFACE PROPERTIES
TELESCOPES