[CEA] A physical model for the redshift evolution of high-z Lyman-Break Galaxies


We present a semi analytic galaxy formation model to understand the evolution of stellar mass – UV luminosity relations, stellar mass functions and specific star formation rate (sSFR) of Lyman Break Galaxies (LBGs) along with their UV luminosity functions in the redshift range 3 < z < 8. We use a physical model for star formation in galaxies and the model parameters are calibrated by fitting the observed UV luminosity functions of LBGs. The fraction of baryons that gets converted into stars remains nearly constant for z > 4 but shows an increase for z < 4. However, the rate of converting baryons into stars do not evolve significantly in the redshift range 3 < z < 8. Thus, dark matter halo build up in LCDM model is sufficient to explain the evolution of UV luminosity functions of LBGs in this redshift range. This model further successfully explains the the stellar mass – UV luminosity correlations of LBGs. While our model predictions of stellar mass functions compare well with the inferred data from observations at the low mass end, we need to invoke the Eddington bias to fit the high mass end. We find that at any given redshift the sSFR to be constant over the stellar mass range 5×10^8 – 5×10^9 M_*/Mo and the redshift evolution of sSFR is well approximated by (1+z)^2.4 for 3 < z < 8 which is consistent with observations.

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Date added: Wed, 16 Oct 13