Ultraviolet Radiation from Evolved Stellar Populations. I. Models

Ultraviolet Light from Old Stellar Populations

We consider the general theoretical problem of ultraviolet light from old stellar populations (t∼>2Gyr), and the interpretation of galaxy spectra at short (λ < 3000 Å). The sources believed to be responsible for the observed ‘ultraviolet upturn phenomenon’ (UVX) are Post-AGB (P-AGB), extreme horizontal branch (EHB) and AGB-Manqué (AGBM) stars. All of these have observational counterparts in old...

Mid-UV Narrow-Band Indices of Evolved Simple Stellar Populations

We explore the properties of selected mid-ultraviolet (1900–3200 Å) spectroscopic indices of simple stellar populations (SSPs). We incorporate the high resolution UVBLUE stellar spectral library into an evolutionary population synthesis code, based on the most recent Padova isochrones. We analyze the trends of UV indices with respect to age and chemical composition. As a first test against obse...

Synthetic stellar populations: single stellar populations, stellar interior models and primordial proto-galaxies

We present a new set of stellar interior and synthesis models for predicting the integrated emission from stellar populations in star clusters and galaxies of arbitrary age and metallicity. This work differs from existing spectral synthesis codes in a number of important ways, namely (1) the incorporation of new stellar evolutionary tracks, with sufficient resolution in mass to sample rapid sta...

Cataract from Ultraviolet Radiation

Models for Massive Stellar Populations with Rotation

We present and discuss evolutionary synthesis models for massive stellar populations generated with the Starburst99 code in combination with a new set of stellar evolution models accounting for rotation. The new stellar evolution models were compiled from several data releases of the Geneva group and cover heavy-element abundances ranging from twice solar to one fifth solar. The evolution model...