The ultraviolet spectra of normal elliptical galaxies : a population synthesis approach.

Abstract

Published UV spectra of elliptical galaxies are compared with the results of population syntheses (based on HB stars, accreting white dwarfs in binary systems, or young stars forming in bursts) in an attempt to explain the observed upturn shortward of 200 nm. The results are presented in tables and spectra and discussed in detail. Good agreement is obtained either with an HB-star model with a bimodal (log Te = 4.30 and 3.75) temperature distribution, or with a young-star model which assumes high star-formation efficiency and a flatter mass function than that of the Galaxy, or with an accreting-white-dwarf model, although only the young-star model can reproduce the wide range of UV intensities seen in the observations.