skip to main content

Title: PROBING THE DAWN OF GALAXIES AT z {approx} 9-12: NEW CONSTRAINTS FROM HUDF12/XDF AND CANDELS DATA

We present a comprehensive analysis of z > 8 galaxies based on ultra-deep WFC3/IR data. We exploit all the WFC3/IR imaging over the Hubble Ultra-Deep Field from the HUDF09 and the new HUDF12 program, in addition to the HUDF09 parallel field data, as well as wider area imaging over GOODS-South. Galaxies are selected based on the Lyman break technique in three samples centered around z {approx} 9, z {approx} 10, and z {approx} 11, with seven z {approx} 9 galaxy candidates, and one each at z {approx} 10 and z {approx} 11. We confirm a new z {approx} 10 candidate (with z = 9.8 {+-} 0.6) that was not convincingly identified in our first z {approx} 10 sample. Using these candidates, we perform one of the first estimates of the z {approx} 9 UV luminosity function (LF) and improve our previous constraints at z {approx} 10. Extrapolating the lower redshift UV LF evolution should have revealed 17 z {approx} 9 and 9 z {approx} 10 sources, i.e., a factor {approx}3 Multiplication-Sign and 9 Multiplication-Sign larger than observed. The inferred star formation rate density (SFRD) in galaxies above 0.7 M{sub Sun} yr{sup -1} decreases by 0.6 {+-} 0.2 dex from zmore » {approx} 8 to z {approx} 9, in excellent agreement with previous estimates. From a combination of all current measurements, we find a best estimate of a factor 10 Multiplication-Sign decrease in the SFRD from z {approx} 8 to z {approx} 10, following (1 + z){sup -11.4{+-}3.1}. Our measurements thus confirm our previous finding of an accelerated evolution beyond z {approx} 8, and signify a very rapid build-up of galaxies with M{sub UV} < -17.7 mag within only {approx}200 Myr from z {approx} 10 to z {approx} 8, in the heart of cosmic reionization.« less
Authors:
; ;  [1] ; ; ;  [2] ;  [3] ;  [4] ;  [5] ;  [6]
  1. UCO/Lick Observatory, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States)
  2. Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands)
  3. Department of Astronomy, Yale University, New Haven, CT 06520 (United States)
  4. Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)
  5. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
  6. University of California, Riverside, 900 University Avenue, Riverside, CA 92507 (United States)
Publication Date:
OSTI Identifier:
22131050
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 773; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DENSITY; GALACTIC EVOLUTION; GALAXIES; LIMITING VALUES; LUMINOSITY; PROBES; RED SHIFT; STARS; ULTRAVIOLET RADIATION