2010/04/30 by Nimish P. Hathi, N. P. Hathi, Russell E. Ryan +44 · 2 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Galaxies: Formation, Evolution, Phenomena #Radio Astronomy Observations and Technology #astro-ph.CO
paper · pdf · doi:10.1088/0004-637x/720/2/1708
published as Astrophys.J.720:1708-1716,2010 · Accepted for publication in ApJ (24 pages, 7 figures)
arxiv created 2010/07/21 · openalex publication_date 2010/08/25 · arxiv updated 2015/05/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We combine new high sensitivity ultraviolet (UV) imaging from the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope ( HST ) with existing deep HST /Advanced Camera for Surveys optical images from the Great Observatories Origins Deep Survey (GOODS) program to identify UV-dropouts, which are Lyman break galaxy (LBG) candidates at z ≃ 1–3. These new HST /WFC3 observations were taken over 50 arcmin 2 in the GOODS-South field as a part of the Early Release Science program. The uniqueness of these new UV data is that they are observed in three UV/optical (WFC3 UVIS) channel filters (F225W, F275W, and F336W), which allows us to identify three different sets of UV-dropout samples. We apply Lyman break dropout selection criteria to identify F225W-, F275W-, and F336W-dropouts, which are z ≃ 1.7, 2.1, and 2.7 LBG candidates, respectively. We use multi-wavelength imaging combined with available spectroscopic and photometric redshifts to carefully access the validity of our UV-dropout candidates. Our results are as follows: (1) these WFC3 UVIS filters are very reliable in selecting LBGs with z ≃ 2.0, which helps to reduce the gap between the well-studied z ≳ 3 and z ∼ 0 regimes; (2) the combined number counts with average redshift z ≃ 2.2 agree very well with the observed change in the surface densities as a function of redshift when compared with the higher redshift LBG samples; and (3) the best-fit Schechter function parameters from the rest-frame UV luminosity functions at three different redshifts fit very well with the evolutionary trend of the characteristic absolute magnitude, M *, and the faint-end slope, α, as a function of redshift. This is the first study to illustrate the usefulness of the WFC3 UVIS channel observations to select z ≲ 3 LBGs. The addition of the new WFC3 on the HST has made it possible to uniformly select LBGs from z ≃ 1 to z ≃ 9 and significantly enhance our understanding of these galaxies using HST sensitivity and resolution.