The UDF05 follow-up of the Hubble Ultra Deep Field. I. The faint-end slope of the Lyman Break Galaxy Population at z ~ 5

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.

doi:10.1086/522423

The UDF05 follow-up of the Hubble Ultra Deep Field. I. The faint-end slope of the Lyman Break Galaxy Population at z ~ 5

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.

Authors

P.A. Oesch

M. Stiavelli

C.M. Carollo

L.E. Bergeron

A.M. Koekemoer

R.A. Lucas

C.M. Pavlovsky

M. Trenti

S.J. Lilly

S.V.W. Beckwith

T. Dahlen

H.C. Ferguson

J.P. Gardner

Professor Cedric Lacey cedric.lacey@durham.ac.uk
Professor

B. Mobasher

N. Panagia

H.-W. Rix

Abstract

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 α ~ − 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.

Citation

Oesch, P., Stiavelli, M., Carollo, C., Bergeron, L., Koekemoer, A., Lucas, R., …Rix, H. (2007). The UDF05 follow-up of the Hubble Ultra Deep Field. I. The faint-end slope of the Lyman Break Galaxy Population at z ~ 5. Astrophysical Journal, 671(2), Article 1212. https://doi.org/10.1086/522423

Journal Article Type	Article
Publication Date	Dec 20, 2007
Deposit Date	Jun 27, 2014
Publicly Available Date	Jan 28, 2015
Journal	Astrophysical Journal
Print ISSN	0004-637X
Electronic ISSN	1538-4357
Publisher	American Astronomical Society
Peer Reviewed	Peer Reviewed
Volume	671
Issue	2
Article Number	1212
DOI	https://doi.org/10.1086/522423
Keywords	Dark matter, Galaxies: evolution, Galaxies: formation, Galaxies: high-redshift, Galaxies: luminosity function, mass function.