Evolutionary stellar population synthesis at 2 angstrom spectral resolution

I present an evolutionary stellar population synthesis model which predicts spectral energy distributions, SEDs, for simple old single-metallicity ste llar populations, SSPs, in the wavelength intervals lambda lambda 3856-4476 Angstrom and 4795-5465 Angstrom at a resolution of FWHM = 1.8 Angstrom, on the basis of an extensive empirical spectral library composed of approxima te to 550 stars. The synthesized model spectra can be used to analyse obser ved galaxy spectra in a very easy and flexible way, allowing us to adapt th e theoretical predictions to the characteristics of the data instead of pro ceeding in the opposite direction (as we must do,for example, when transfor ming observational data to a particular system of indices at specific resol ution/s, such as Lick, which is heavily instrument-dependent). The SSP spec tra, with flux-calibrated response curves, can be smoothed to the same reso lution as that of the data or to galaxy internal velocity dispersion, allow ing us to analyse the observed spectra in their own system, and with no nee d to correct the index measurements for velocity dispersion. Thus, we are a ble to use all the information contained in the data, at their higher spect ral resolution. Excellent fits are obtained for various metal-rich globular clusters at relatively high resolution, and well known spectral peculiarit ies such as the strong CN absorption features are detected. When applied to early-type galaxies the model also shows its potential for studying elemen t ratios such as the Mg/Fe overabundance. The model spectra provided robust age indicators for old stellar populations which do not depend on metallic ity and therefore have a great potential for solving the age-metallicity de generacy of galaxy spectra.