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 tmoxgroup@googlemail.com.

24 February 2012

Growth of early SMBH and high redshift Eddington Ratio Distributions

This paper (link) uses a cosmological hydro simulation to explore the Edd. Ratios (ER) of the black holes that they seed in their simulation. A BH of mass 10^5 SM is seeded in haloes over 10^10 SM. They allow for Bondi-Hoyle Accretion with a modified parameter for the gas density close to the BH and compare it with Edd. Accretion to get the ERs. Various feedback effects are accounted for and they also plot the ER carefully so as to avoid any inherent trends. They find that the ER depends mostly on the the density of the gas being accreted.

They fit a universal log-normal distribution to the Edd. Ratio and compare it with observations. The Edd. Ratios they find are mostly < 1 implying sub-Eddnington accretion for the massive BH seeds in their work.
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