The Shapes and Ages of Elliptical Galaxies

Conference item

In this paper we investigate the relation between the detailed isophotal shape of elliptical galaxies and the strength of the H beta absorption in their spectra. We find that disky galaxies have higher H beta indices. Stellar population synthesis models show that the H beta line is a good age indicator, hence disky galaxies tend to have younger mean ages than boxy galaxies. We show that the observed trend can be brought about by a contaminating young population, which we associate with the disky component. This population need only account for a small fraction of the total mass, for example if a contaminating population of age of 2 Gyrs is superimposed on an old (12 Gyr) elliptical galaxy, then the observed trend can be explained if it contributes only 10% to the total mass. The size of this effect is consistent with the estimates of disk-to-total light ratios from surface photometry.

Authors: Jong, R; Davies, R

• Publication status: Published
• Host title: NEW LIGHT ON GALAXY EVOLUTION
• Issue: 171
• Pages: 359-359
• Publication date: 1996-11-13
• ISSN: 0074-1809
• ISBN: 0792339754
• Keywords: astro-ph