The Long Faint Tail of the High-Redshift Galaxy Population
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We study the properties of very faint, sub-L* Lyman break galaxies at z~2-5 - thus far a largely neglected but numerically and energetically very important population. We find that the LBG luminosity function undergoes luminosity-dependent evolution: the number of luminous galaxies remains constant while the number of faint ones grows with time. The total UV luminosity density increases with cosmic time from at least z~5 until reaching a peak or a plateau around z~2 - behaviour that is governed by the sub-L* galaxies in the LF's "faint tail". Using broadband SED fitting we find a nearly-linear relationship between SFR and galaxy stellar mass at z~2. A typical L* LBG at z~2 shows a stellar mass of ~10^10M_sun, remarkably similar to the bimodality mass at low redshift. This similarity suggests that the mechanisms responsible for the galaxy bimodality at low-z may have also been at play at z~2.
To appear in the proceedings of 'At the Edge of the Universe', October 2006, Sintra, Portugal
To appear in the proceedings of 'At the Edge of the Universe', October 2006, Sintra, Portugal