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90 GHz and 150 GHz Observations of the Orion M42 Region. A Submillimeter to Radio AnalysisWe have used the new 90GHz MUSTANG camera on the Robert C. 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. 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 OMCI 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 31 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 OMCI interface to the denser UV shielded part OMCI (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 micrometers).
Document ID
20100032042
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Dicker, S. R.
(Pennsylvania Univ. Philadelphia, PA, United States)
Mason, B. S.
(National Radio Astronomy Observatory Charlottesville, VA, United States)
Korngut, P. M.
(Pennsylvania Univ. Philadelphia, PA, United States)
Cotton, W. D.
(National Radio Astronomy Observatory Charlottesville, VA, United States)
Compiegne, M.
(Toronto Univ. Ontario, Canada)
Devlin, M. J.
(Pennsylvania Univ. Philadelphia, PA, United States)
Martin, P. G.
(Toronto Univ. Ontario, Canada)
Ade, P. A. R
(Cardiff Univ. United Kingdom)
Benford, D. J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Irwin, K. D.
(National Inst. of Standards and Technology Boulder, CO, United States)
Maddalena, R. J.
(National Radio Astronomy Observatory Green Bank, WV, United States)
McMullin, J. P.
(National Radio Astronomy Observatory Green Bank, WV, United States)
Shepherd, D. S.
(National Radio Astronomy Observatory Green Bank, WV, United States)
Sievers, A.
(Instituto de Radioastronomia Granada, Spain)
Staguhn, J. G.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Tucker, C.
(Cardiff Univ. United Kingdom)
Date Acquired
August 25, 2013
Publication Date
November 1, 2009
Publication Information
Publication: The Astrophysical Journal
Volume: 705
Issue: 1
Subject Category
Astrophysics
Funding Number(s)
CONTRACT_GRANT: AST-0705185
CONTRACT_GRANT: AST-0607654
Distribution Limits
Public
Copyright
Other

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