Abstract
The process that quenched star formation in galaxies at intermediate and
high redshifts is still the subject of considerable debate. One way to
investigate this puzzling issue is to study the number density of
quiescent galaxies at z ≃ 2 and its dependence on mass. Here we
present the results of a new study based on very deep Ks-band
imaging (with the HAWK-I instrument on the VLT) of two HST CANDELS
fields (the UKIDSS Ultra-deep survey (UDS) field and GOODS-South). The
new HAWK-I data (taken as part of the HUGS VLT Large Program) reach
detection limits of Ks> 26 (AB mag). We have combined this
imaging with the other ground-based and HST data in the CANDELS fields
to select a sample of passively-evolving galaxies in the redshift range
1.4 23 a higher redshift
population of z ≃ 3pBzK galaxies is detected and dominates the
counts at the faintest magnitudes. Finally, we compare the observed pBzK
number counts with those of quiescent galaxies extracted from four
different semi-analytic models. We find that only two of these models
reproduce the observed trend in the number counts, even qualitatively,
and that none of the models provides a statistically acceptable
description of the number density of quiescent galaxies at these
redshifts. We conclude that the mass function of quiescent galaxies as a
function of redshift continues to present a key and demanding challenge
for proposed models of galaxy formation and evolution.
Original language | English |
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Article number | A99 |
Number of pages | 13 |
Journal | Astronomy & Astrophysics |
Volume | 571 |
Publication status | Published - 1 Nov 2014 |
Keywords
- Galaxy: fundamental parameters
- galaxies: high-redshift