Open AccessA deeper view of extremely red galaxies: the redshift distribution in the GOODS/CDFS ISAAC field
Author(s) -
Caputi K. I.,
Dunlop J. S.,
McLure R. J.,
Roche N. D.
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.08044.x
Subject(s) - physics , redshift , galaxy , astrophysics , astronomy , field (mathematics) , red shift , galaxy formation and evolution , redshift survey , mathematics , pure mathematics
We have analysed five‐epoch Great Observatories Origins Deep Survey (GOODS) HST –ACS B , V , I 775 and z data sets (v. 1.0 release), in conjunction with existing VLT–ISAAC imaging in the J , H and K s bands, to derive estimated redshifts for the sample of 198 extremely red galaxies (ERGs) with K s < 22 (Vega) and ( I 775 − K s ) > 3.92 selected by Roche, Dunlop & Almaini (2003) from 50.4 arcmin 2 of the GOODS/ Chandra Deep Field South. We find that, at this depth, the ERG population spans the redshift range 0.5 < z phot < 4.75 and over two decades in mass ( ∼3 × 10 9 M ⊙ to ∼3 × 10 11 M ⊙ ). Our results show that the dust‐corrected red envelope of galaxy evolution is well modelled by a starburst at redshift z f = 5 followed thereafter by passive evolution. We explore the evolution of the ERG luminosity function (LF) from redshifts 〈 z phot 〉= 1.0 to 〈 z phot 〉= 2.5 and compare it with the global K s ‐band LF at redshifts 1 < z phot < 2 . We find that the bright end of the ERG LF does not decrease from redshifts 〈 z phot 〉= 2.0 to 〈 z phot 〉= 2.5 and we connect this fact with the presence of progenitors of the local L > L * population at redshifts z phot > 2 . We determine lower limits of ρ c = (6.1 ± 1.9) × 10 −5 Mpc −3 and ρ c = (2.1 ± 1.1) × 10 −5 Mpc −3 on the comoving densities of progenitors of local massive galaxies already assembled at redshifts 〈 z phot 〉= 2.5 and 〈 z phot 〉= 3.5 , respectively. We have investigated the existence of high‐redshift Lyman‐break galaxies massive enough to be included in this ERG sample. Out of an initial list of 12 potential very high redshift candidates, we have identified two ERGs which have a high probability of lying at z phot > 4 . We discuss the advantages of multicolour to single‐colour selection techniques in obtaining reliable lists of very high redshift candidate sources, and present revised lower redshift estimates for sources previously claimed as potential z > 5 dropouts in recent studies.