Hierarchical models of high-redshift galaxies with thermally pulsing asymptotic giant branch stars: comparison with observations

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Title: Hierarchical models of high-redshift galaxies with thermally pulsing asymptotic giant branch stars: comparison with observations
Author(s): Tonini, Chiara; Maraston, Claudia; Thomas, Daniel; Devriendt, Julien; Silk, Joseph
Abstract: In a recent paper, we presented the first semi-analytic model of galaxy formation in which the thermally pulsing asymptotic giant branch (TP-AGB) phase of stellar evolution has been fully implemented. Here, we address the comparison with observations, and show how the TP-AGB recipe affects the performance of the model in reproducing the colours and near-infrared luminosities of high-redshift galaxies. We find that the semi-analytic model with the TP-AGB better matches the colour-magnitude and colour-colour relations at z ~ 2, both for nearly passive and for star-forming galaxies. The model with TP-AGB produces star-forming galaxies with red V - K colours, thus revising the unique interpretation of high-redshift red objects as 'red and dead'. We also show that without the TP-AGB the semi-analytic model fails at reproducing the observed colours, a situation that cannot be corrected by dust reddening. We also explore the effect of nebular emission on the predicted colour-magnitude relation of star-forming galaxies, to conclude that it does not play a significant role in reddening their colours, at least in the range of star-formation rates covered by the model. Finally, the rest-frame K-band luminosity function at z ~ 2.5 is more luminous by almost 1 mag. This indicates that the active galactic nuclei feedback recipe that is adopted to regulate the high-mass end of the luminosity function should be sophisticated to take the effect of the stellar populations into account at high redshifts.
Publication type: Journal article
Source: Monthly Notices of the Royal Astronomical Society, Vol. 403, no. 4 (Apr 2010), pp. 1749-1758
Publication year: 2010
FOR Code(s): 0201 Astronomical and Space Sciences
Keyword(s): Fundamental parameters; Galaxies; Galaxy evolution; Galaxy formation; High-redshift galaxies; Infrared; Luminosity function; Mass function
Publisher: Wiley-Blackwell
ISSN: 0035-8711
Publisher URL: http://dx.doi.org/10.1111/j.1365-2966.2009.16231.x
Peer reviewed