  PEGASE is a new spectrophotometric evolution model for starbursts and evolved
galaxies of the Hubble sequence. Its main originality is the extension to the
near-infrared (NIR) of the atlas of synthetic spectra of Rocca-Volmerange &
Guiderdoni (1988) with a revised stellar library including cold star parameters
and stellar tracks extended to the TP-AGB and the post-AGB phase. The NIR is
coherently linked to the visible and the ultraviolet, so that the model is
continuous on an exceptionally large wavelength range from 220 A up to 5
microns. Moreover, a precise algorithm allows to follow very rapid evolutionary
phases such as red supergiants or AGB crucial in the NIR. The nebular component
is also computed in the NIR. The extinction correction is gas-dependent for
spirals and ellipticals. A set of reference synthetic spectra at z=0, to which
apply cosmological k- and evolution e- corrections for high-redshift galaxies,
is built from fits of observational templates. Because of the lack of visible
to NIR spectral templates for each Hubble type, we adopt statistical samples of
colors, not fitted by previous models. A first application of this continuous
model is to solve the problem of the slope of the bright galaxy counts from
B=15 to 19 and of the normalization parameter of the Schechter luminosity
function. Code sources, input and output data are available by anonymous ftp or
at the WEB address of the authors.
