Abstract
We present our most recent population synthesis models of elliptical galaxies.
Each elliptical galaxy is represented as a simple stellar population (a group
of stars having a common age and metallicity). The effective temperature,
surface gravity distribution of the stars in each galaxy can thus be specified
by a single isochrone. The models presented here differ from our previous
work (Houdashelt & Bell 1996, Bell & Houdashelt 1996) in the use of a new set
of isochrones, which have been constructed from the evolutionary tracks of
Sweigart (1996). Using updated MARCS stellar atmosphere models, we have
calculated synthetic stellar spectra with the SSG spectral synthesis code for
a representative sample of stars along 4-20 Gyr isochrones of three
metallicities. Assuming a Salpeter initial mass function, we have determined
luminosity functions (LFs) for each of these isochrones and used these LFs to
construct integrated synthetic spectra of elliptical galaxies. We present
examples of our spectra here and explore the effects of changes in the age
and metallicity of the stellar population on the optical and near-infrared
(0.3-3 micron) regions of the spectral energy distribution. Broad-band colors
derived from our models are compared to the model colors of Worthey (1994)
and to the observed colors of early-type galaxies.
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