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High Frequency Measurements of the Spectrum of Sgr A(sup *)We report near-simultaneous interferometric measurements of the spectrum of Sgr A(sup *) over the 5 to 354 GHz range, and single-dish observations which have yielded the first detection of Sgr A(sup *) at 850 GHz. We confirm that Sgr A(sup *)'s spectrum rises more steeply at short mm wavelengths than at cm wavelengths, leading to a near-millimeter/submillimeter excess which dominates its luminosity. Below 900 GHz, Sgr A(sup *)'s observed luminosity is 70 +/- 30 solar luminosity). A new upper limit to Sgr A(sup *)'s 24.3 microns flux, together with a compilation of other extant IR data, imply a FIR spectral turnover, which can result either from an intrinsic synchrotron cutoff, or excess extinction near Sgr A(sup *). If the former applies, Sgr A(sup *)'s total synchrotron luminosity is less than 10(exp 3) solar luminosity, while in the latter case it is less than 3 x 10(exp 4) solar luminosity if spherical symmetry also applies.
Document ID
19990008347
Acquisition Source
Ames Research Center
Document Type
Reprint (Version printed in journal)
Authors
Serabyn, E.
(California Inst. of Tech. Pasadena, CA United States)
Carlstrom, J. E.
(Chicago Univ. Chicago, IL United States)
Lay, O.
(NASA Ames Research Center Moffett Field, CA United States)
Lis, D. C.
(California Inst. of Tech. Pasadena, CA United States)
Hunter, T. R.
(Smithsonian Astrophysical Observatory Cambridge, MA United States)
Lacy, J. H.
(Hawaii Univ. Honolulu, HI United States)
Hills, R. E.
(Mullard Radio Astronomy Observatory Cambridge, United Kingdom)
Date Acquired
August 19, 2013
Publication Date
October 1, 1997
Publication Information
Publication: Astrophysical Journal Letters
Subject Category
Astronomy
Funding Number(s)
CONTRACT_GRANT: NSF AST 96-13717
CONTRACT_GRANT: NSF AST-96-15025
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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