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 March 2011

An Evolving Stellar Initial Mass Function and the Gamma-ray Burst Redshift Distribution

Link to paper here.
Authors: Wang & Dai

Whether or not the gamma-ray burst rate tracks the overall star formation rate in the universe has been a topic of much interest and debate. In particular, with the ever-growing sample of GRBs at high redshift, it appears that the GRB rate rises faster with redshift than the star formation rate. It has been suggested that this is due to GRB progenitors being of preferentially low metallicity, but some observations show GRBs exploding in metal-rich galaxies so this may not provide a clear explanation for the dicrepancy. In this paper, the authors show that an IMF, such as that suggested by Dave (2010), which becomes more top-heavy at higher redshifts can explain the discrepancy between the star formation rate and the GRB rate.

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