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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 358635.0, MPI für Astronomie / Publikationen_mpia
The UDF05 follow-up of the Hubble Ultra Deep Field. I. The faint-end slope of the Lyman Break galaxy population at z ~ 5
Authors:Oesch, P. A.; Stiavelli, M.; Carollo, C. M.; Bergeron, L. E.; Koekemoer, A. M.; Lucas, R. A.; Pavlovsky, C. M.; Trenti, M.; Lilly, S. J.; Beckwith, S. V. W.; Dahlen, T.; Ferguson, H. C.; Gardner, J. P.; Lacey, C.; Mobasher, B.; Panagia, N.; Rix, H. W.
Date of Publication (YYYY-MM-DD):2007
Title of Journal:The Astrophysical Journal
Start Page:1212
End Page:1226
Audience:Not Specified
Abstract / Description:We present the UDF05 HST program, which consists of three disjoint fields-NICP12, NICP34, plus the HUDF-with deep ACS (F606W, F775W, and F850LP) and NICMOS (F110W and F160W) imaging. Here we use the ACS data for the NICP12 and HUDF fields to implement a (V-i)-(i-z) selection criterion that allows us to identify a sample of 101 (133) z~5 Lyman break galaxies (LBGs) down to z850=28.5 (29.25) mag in NICP12 (HUDF). We construct the rest-frame 1400 Å LBG luminosity function (LF) over the range M1400=[-21.4,-17.1], i.e. down to ~0.04L* at z~5, and use Subaru Deep Field results (Yoshida et al. 2006) to constrain our LF at the bright end (M1400>=-22.2). We show that (1) different assumptions regarding the LBG SED distribution, dust properties, and intergalactic absorption result in a 25% variation in the number density of LBGs at z~5 (2) under consistent assumptions for dust properties and intergalactic absorption, the HUDF is ~30% underdense in z~5 LBGs relative to the NICP12 field, a variation which is well explained by cosmic variance; and (3) the faint-end slope of the LF does not depend on the input parameters, and has a value of alpha~-1.6, similar to the faint-end slope of the LF of z~3 and z~6 LBGs. Our study therefore supports no variation in the faint end of the LBG LF over the whole redshift range z~3 to z~6. Based on a comparison with semianalytical models, we speculate that the z~5 LBGs might have a top-heavy IMF. Based on data obtained with the Hubble Space Telescope operated by the Association of Universities for Research in Astronomy, Inc., for NASA under contract NAS5-26555.
Free Keywords:Cosmology: Dark Matter; Galaxies: Evolution; Galaxies: Formation; Galaxies: High-Redshift; Galaxies: Luminosity Function; Mass Function
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
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