This is the astro-ph blog of the Theoretical Modelling of Cosmic Structures group (TMoX) at the Max-Planck-Institute for Extraterrestrial Physics. We are an independent Max-Planck Research Group focusing on the various aspects in the formation and evolution of galaxies. Part of our focus is on the formation and evolution of early-type galaxies, super-massive black holes, the formation of the first structures in the universe and the enrichment history of the Universe. We are theoreticians using analytic modelling as well as numerical simulations in our work.

The CosmologyCake blog is dedicated to the discussion of research papers and current developments. We will regularly post interesting papers and comment on them. Feel free to leave your comments as well. We encourage authors of discussed papers to post replies if they wish to. Our aim is to provide a platform to discuss recent astro-ph papers within a wider audience. Please feel free to send papers you would like to be discussed to us at

27 September 2010

Transformations in the Fall: The Birth of the Early-Type Galaxies

The authors discuss in their paper (Feldmann et al. 2010; arXiv:1008.3386a recent high resolution cosmological hydro simulation of the formation of a galaxy group environment. The remarkable feature of their simulation is to be able to resolve the detailed formation history of individual group members with high mass resolution (SPH particle mass = 1E6 M_sun). Their main conclusion is that elliptical galaxies form by major mergers before the assembly of the group, and that gas cooling and associated star formation is strongly suppressed via ram-pressure stripping once galaxies enter the group environment.

1 comment:

  1. I think it is a clear step forward to simulate groups within a cosmological setting with high resolution. However, I think the authors could have shown more detailed comparisons to the properties of locally observed elliptical galaxies. In particular comparisons to SAURON observations or the work of Bender et al or Faber et al would have been useful. This would have helped to strengthen their claims on the formation of ellipticals. One point that I am very curious about is the metallicities, and in particular the alpha/Fe abundance of their simulated ellipticals.