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The Long Faint Tail of the High-Redshift Galaxy Population

Marcin Sawicki·Ikuru Iwata·Kouji Ohta·David Thompson·Naoyuki Tamura·Masayuki Akiyama·Kentaro Aoki·Masataka Ando·Gaku Kiuchi
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Abstract

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.

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Marcin Sawicki, Ikuru Iwata, Kouji Ohta, David Thompson, Naoyuki Tamura, Masayuki Akiyama, Kentaro Aoki, Masataka Ando, Gaku Kiuchi. 2006-12-05. The Long Faint Tail of the High-Redshift Galaxy Population. https://arxiv.org/abs/astro-ph/0612117

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