THE UDF05 FOLLOW-UP OF THE HUBBLE ULTRA DEEP FIELD. III. THE LUMINOSITY FUNCTION AT z {approx} 6
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States)
- Space Telescope Science Institute, Baltimore, MD 21218 (United States)
- Institute of Astrophysics, ETH Zurich, CH-8093 Zurich (Switzerland)
- Department of Astrophysical and Planetary Sciences, University of Colorado, CASA, 389-UCB, Boulder, CO 80309 (United States)
- Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)
- Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States)
In this paper, we present a derivation of the rest-frame 1400 A luminosity function (LF) at redshift six from a new application of the maximum likelihood method by exploring the five deepest Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) fields, i.e., the Hubble Ultra Deep Field, two UDF05 fields, and two Great Observatories Origins Deep Survey fields. We work on the latest improved data products, which makes our results more robust than those of previous studies. We use unbinned data and thereby make optimal use of the information contained in the data set. We focus on the analysis to a magnitude limit where the completeness is larger than 50% to avoid possibly large errors in the faint end slope that are difficult to quantify. We also take into account scattering in and out of the dropout sample due to photometric errors by defining for each object a probability that it belongs to the dropout sample. We find the best-fit Schechter parameters to the z {approx} 6 LF are {alpha} = 1.87 {+-} 0.14, M{sub *} = -20.25 {+-} 0.23, and {phi}{sub *} = 1.77{sup +0.62}{sub -0.49} x 10{sup -3} Mpc{sup -3}. Such a steep slope suggests that galaxies, especially the faint ones, are possibly the main sources of ionizing photons in the universe at redshift six. We also combine results from all studies at z {approx} 6 to reach an agreement in the 95% confidence level that -20.45 < M{sub *} < -20.05 and -1.90 < {alpha} < -1.55. The luminosity density has been found not to evolve significantly between z {approx} 6 and z {approx} 5, but considerable evolution is detected from z {approx} 6 to z {approx} 3.
- OSTI ID:
- 21584897
- Journal Information:
- Astrophysical Journal, Vol. 738, Issue 2; Other Information: DOI: 10.1088/0004-637X/738/2/123; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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