Proceedings of the International Astronomical Union

Contributed Papers

Stellar Population gradients in early-type galaxies

Patricia Sánchez-Blázqueza1 p1, Duncan Forbesa2, Jay Stradera3, Pierre Ocvirka4, Jean Brodiea3 and Robert Proctora4

a1 University of Central Lancashire, PR1 2HE, Preston, UK

a2 Swinburne University of Technology, Hawthorn, Australia

a3 UCO/Lick Observatory, University of California, Santa Cruz, CA 95064, USA

a4 CEASaclay, L'Orme des Merisiers, 91191 Gif-sur-Yvette, Cedex, France


Long-slit spectra have been obtained with the Keck telescope for a sample of 11 early-type galaxies covering a range in luminosity. Rotation velocity and velocity dispersions, together with 20 Lick line-strength gradients have been measured to two effective radius. We transform line-strength gradients into age, metallicity and α/Fe. Galaxies show very shallow age gradients, strong metallicity gradients, and both positive and negative α/Fe gradients, which cannot be explained with simple outside-in scenarios of galaxy formation. We explore the correlation of the gradients with other global parameters of the galaxies, finding different behaviour for the two families of galaxies, luminous (boxy, core inner profile) and less luminous (disky, cuspy inner profile) galaxies.


  • galaxies: elliptical and lenticular;
  • cD;
  • galaxies: formation;
  • galaxies: stellar content


p1 Present