From stolovy@astrosun.tn.cornell.edu Wed Jul 17 23:12:09 1996
From: Susan Stolovy <stolovy@astrosun.tn.cornell.edu>
Date: Wed, 17 Jul 1996 23:11:15 -0400
To: gcnews@astro.umd.edu
Subject: submit abstract_gcnews.tex to appear in ApJ Letters; accepted July 1996


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\begin{document}

\title{The First Mid-Infrared Detection of a Source Coincident with
Sagittarius A*}
\author{Susan R. Stolovy, T. L. Hayward, and Terry Herter}
\affil{Department of Astronomy, Cornell University, Ithaca, NY 14853\\Electronic mail: stolovy, hayward, herter@astrosun.tn.cornell.edu}

\begin{abstract}
\rm
We present the first mid-infrared detection of a source coincident with the
black hole candidate Sgr A* in a deep image of the inner parsec of the
Galaxy.  These data were obtained with SpectroCam-10 at the 200-inch Hale 
telescope.  The source was detected at 8.7 $\mu$m on two separate occasions using different observing techniques. The spatial resolution is $\sim$ 0\farcs7 and the noise level is 1.6 mJy beam$^{-1}$ in the combined mosaic near Sgr A*.  A source at Sgr A* is weakly apparent in the raw data, but is difficult to identify due to strong diffuse dust emission with a mean flux density of 500 mJy arcsec$^{-2}$.  Several deconvolution techniques were applied to achieve the diffraction limit of 0\farcs44, all of which revealed a peak on a narrow NW-SE ridge of emission.  The peak is coincident with Sgr A* within the 
$\pm$0\farcs3 uncertainty in locating Sgr A* relative to IRS 7.  We estimate the flux density of the Sgr A* source above the ridge to be 25 $\pm$ 5 mJy.  The extinction-corrected 8.7 $\mu$m flux density of $\sim$ 100 mJy is significantly greater than what is predicted by dustless accretion disk models.  The excess emission is best explained by warm dust which may be associated with Sgr A* or heated by local stellar sources.
  
\end{abstract}
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