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Title: THE UV CONTINUUM OF z > 1 STAR-FORMING GALAXIES IN THE HUBBLE ULTRAVIOLET ULTRADEEP FIELD

We estimate the UV continuum slope, β, for 923 galaxies in the range 1 < z < 8 in the Hubble Ultradeep Field (HUDF). These data include 460 galaxies at 1 < z < 2 down to an absolute magnitude M{sub UV}=−14(∼0.006 L{sub z=1}{sup ∗};0.02 L{sub z=0}{sup ∗}), comparable to dwarf galaxies in the local universe. We combine deep HST/UVIS photometry in F225W, F275W, F336W wavebands (UVUDF) with recent data from HST/WFC3/IR (HUDF12). Galaxies in the range 1 < z < 2 are significantly bluer than local dwarf galaxies. We find their mean (median) values <β > = – 1.382(– 1.830) ± 0.002 (random) ± 0.1 (systematic). We find comparable scatter in β (standard deviation = 0.43) to local dwarf galaxies and 30% larger scatter than z > 2 galaxies. We study the trends of β with redshift and absolute magnitude for binned sub-samples and find a modest color-magnitude relation, dβ/dM = –0.11 ± 0.01, and no evolution in dβ/dM with redshift. A modest increase in dust reddening with redshift and luminosity, ΔE(B – V) ∼ 0.1, and a comparable increase in the dispersion of dust reddening at z < 2, appears likely to explain the observed trends. At zmore » > 2, we find trends that are consistent with previous works; combining our data with the literature in the range 1 < z < 8, we find a color evolution with redshift, dβ/dz = –0.09 ± 0.01 for low luminosity (0.05 L{sub z=3}{sup ∗}), and dβ/dz = –0.06 ± 0.01 for medium luminosity (0.25 L{sub z=3}{sup ∗}) galaxies.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [4] ; ; ; ;  [5] ;  [6] ;  [7] ;  [8] ;  [9] ;  [10]
  1. Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 (United States)
  2. NASA Postdoctoral Program Fellow, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States)
  3. Infrared Processing and Analysis Center, MS 100-22, Caltech, Pasadena, CA 91125 (United States)
  4. New York City College of Technology, Brooklyn, NY 11201 (United States)
  5. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
  6. Laboratory for Observational Cosmology, Astrophysics Science Division, Code 665, Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
  7. Department of Astronomy, The University of Texas at Austin, Austin, TX 78712 (United States)
  8. Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States)
  9. Minnesota Institute for Astrophysics, School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)
  10. Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States)
Publication Date:
OSTI Identifier:
22365036
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 793; 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; COLOR; COMPARATIVE EVALUATIONS; COSMOLOGY; GALAXIES; LUMINOSITY; PHOTOMETRY; RANDOMNESS; RED SHIFT; STAR EVOLUTION; STARS; ULTRAVIOLET RADIATION; UNIVERSE