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                              G C N E W S
                             * Newsflash *

            - The Newsletter for Galactic Center Research -

gcnews@mpifr-bonn.mpg.de             http://www.mpifr-bonn.mpg.de/gcnews
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Vol. 8, No. 17                                              Jul 30, 1998


Recently submitted papers:
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Email    : kwc@ssa1.arc.nasa.gov
Title    : The Nature of the Mid-Infrared Background Radiation 
           in the Galactic Bulge from the IRTS Observations
Author(s): Kin-Wing Chan(1), T. L. Roellig(1), T. Onaka(2), I. 
           Yamamura(2,4)    T. Tanabe(3)
Institute: (1) NASA/Ames Research Center, MS 245-6, Moffett Field, CA 
           94035;    kwc@ssa1.arc.nasa.gov, roellig@ssa1.arc.nasa.gov   
           (2) Department of Astronomy, University of Tokyo, Bunkyo-ku, 
           Tokyo 113;    onaka@apsun4.astron.s.u-tokyo.ac.jp, 
           yamamura@astron.s.u-tokyo.ac.jp   (3) Institute of 
           Astronomy, University of Tokyo, Mitaka, Tokyo 181;    
           ttanabe@mtk.ioa.s.u-tokyo.ac.jp   (4) present address:  
           Astronomical Institute ``Anton Pannekoek'',        
           University of Amsterdam, Kruislaan 403, NL-1098SJ, 
           Amsterdam, the        Netherlands
Paper    : to appear in ApJ Letters
EPrint   : astro-ph/9807294

Abstract:
Using the Mid-Infrared Spectrometer (MIRS) on board the Infrared
Telescope in Space (IRTS) we obtained the 4.5 to 11.7 micron spectra
of the stellar populations and diffuse interstellar medium in the
Galactic bulge (l ~ 8.7^o, b ~ 2.9, 4.0, 4.7, and 5.7^o). Below
galactic latitudes of 4.0^o, the mid-infrared background spectra in
the bulge are similar to the spectra of M and K giants. The UIR
emission bands (6.2, 7.7, 8.6, and 11.3 micron ) are also detected in
these regions and likely arise from the diffuse interstellar medium in
the disk. Above galactic latitudes of 4.0^o, the mid-infrared
background spectra are similar to the spectra of those oxygen-rich
evolved stars with high mass-loss rates detected by IRAS.  One likely
interpretation is that this background emission arises predominantly
from those stars with very low luminosities that have not been
detected by IRAS. The age for such low-luminosity evolved stars could
be 15 Gyr, and the existence of a large number of evolved stars with
high mass-loss rates in the bulge has a significant impact on our
understanding of the stellar content in the Galactic bulge.
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			       Edited by
Angela Cotera                                Heino Falcke
(cotera@ipac.caltech.edu)                    (hfalcke@mpifr-bonn.mpg.de)
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