UV luminosity functions at Redshifts z ∼ 4 TO z ∼ 10: 10,000 galaxies from HST legacy fields

Journal Article · Fri Apr 10 04:00:00 EDT 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/803/1/34· OSTI ID:22882576

Bouwens, R. J.; Labbé, I.; Holwerda, B.; Franx, M.; Smit, R. ^[1]; Illingworth, G. D.; Oesch, P. A.; Gonzalez, V.; Magee, D. ^[2]; Trenti, M. ^[3]; Bradley, L. ^[4]; Carollo, M. ^[5]; Van Dokkum, P. G. ^[6]

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1. Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands)
2. UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States)
3. Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)
4. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
5. Institute for Astronomy, ETH Zurich, 8092 Zurich (Switzerland)
6. Department of Astronomy, Yale University, New Haven, CT 06520 (United States)

The remarkable Hubble Space Telescope (HST) data sets from the CANDELS, HUDF09, HUDF12, ERS, and BoRG/HIPPIES programs have allowed us to map the evolution of the rest-frame UV luminosity function (LF) from z∼10 to z∼4. We develop new color criteria that more optimally utilize the full wavelength coverage from the optical, near-IR, and mid-IR observations over our search fields, while simultaneously minimizing the incompleteness and eliminating redshift gaps. We have identified 5859, 3001, 857, 481, 217, and 6 galaxy candidates at z∼4, z∼5, z∼6, z∼7, z∼8, and z∼10, respectively, from the ∼1000 arcmin{sup 2} area covered by these data sets. This sample of >10,000 galaxy candidates at z⩾4 is by far the largest assembled to date with HST. The selection of z ∼ 4–8 candidates over the five CANDELS fields allows us to assess the cosmic variance; the largest variations are at z⩾7. Our new LF determinations at z∼4 and z∼5 span a 6 mag baseline and reach to –16 AB mag. These determinations agree well with previous estimates, but the larger samples and volumes probed here result in a more reliable sampling of >L{sup ∗} galaxies and allow us to reassess the form of the UV LFs. Our new LF results strengthen our earlier findings to 3.4σ significance for a steeper faint-end slope of the UV LF at z>4, with α evolving from α=−1.64±0.04 at z∼4 to α=−2.06±0.13 at z∼7 (and α=−2.02±0.23 at z∼8), consistent with that expected from the evolution of the halo mass function. We find less evolution in the characteristic magnitude M{sup *} from z∼7 to z∼4; the observed evolution in the LF is now largely represented by changes in ϕ{sup ∗}. No evidence for a non-Schechter-like form to the z ∼ 4–8 LFs is found. A simple conditional LF model based on halo growth and evolution in the M/L ratio (∝(1+z){sup −1.5}) of halos provides a good representation of the observed evolution.

• OSTI ID: 22882576
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 803; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United Kingdom
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
GALACTIC EVOLUTION
GALAXIES
LUMINOSITY
MASS
RED SHIFT
SPACE
TELESCOPES