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Title: Measurement of galaxy clustering at z ∼ 7.2 and the evolution of galaxy bias from 3.8 < z < 8 in the XDF, GOODS-S, and GOODS-N

Lyman-break galaxy (LBG) samples observed during reionization (z ≳ 6) with the Hubble Space Telescope's Wide Field Camera 3 are reaching sizes sufficient to characterize their clustering properties. Using a combined catalog from the Hubble eXtreme Deep Field and CANDELS surveys, containing N = 743 LBG candidates at z ≥ 6.5 at a mean redshift of z-bar =7.2, we detect a clear clustering signal in the angular correlation function (ACF) at ≳ 4σ, corresponding to a real-space correlation length r{sub 0}=6.7{sub −1.0}{sup +0.9}h{sup −1}cMpc. The derived galaxy bias b=8.6{sub −1.0}{sup +0.9} is that of dark matter halos of M=10{sup 11.1{sub −}{sub 0}{sub .}{sub 3}{sup +{sup 0{sup .{sup 2}}}}} M{sub ⊙} at z = 7.2, and highlights that galaxies below the current detection limit (M{sub AB} ∼ –17.7) are expected in lower-mass halos (M ∼ 10{sup 8}-10{sup 10.5} M{sub ⊙} ). We compute the ACF of LBGs at z ∼ 3.8 – z ∼ 5.9 in the same surveys. A trend of increasing bias is found from z-bar =3.8 (b ∼ 3.0) to z-bar =7.2 (b ∼ 8.6), broadly consistent with galaxies at fixed luminosity being hosted in dark matter halos of similar mass at 4 ≲ z ≲ 6, followedmore » by a slight rise in halo masses at z ≳ 7 (∼2σ confidence). Separating the data at the median luminosity of the z-bar =7.2 sample (M {sub UV} = –19.4) shows higher clustering at z-bar =5.9 for bright galaxies (r{sub 0}=5.5{sub −1.6}{sup +1.4}h{sup −1}cMpc, b=6.2{sub −1.5}{sup +1.2}) compared to faint galaxies (r{sub 0}=1.9{sub −1.0}{sup +1.1}h{sup −1}cMpc, b=2.7{sub −1.2}{sup +1.2}) implying a constant mass-to-light ratio (dlogM/dlogL)∼1.2{sub −0.8}{sup +1.8}. A similar trend is present in the z-bar =7.2 sample with larger uncertainty. Finally, our bias measurements allow us to investigate the fraction of dark matter halos hosting UV-bright galaxies (the duty cycle, ε{sub DC}). At z-bar =7.2 values near unity are preferred, which may be explained by the shortened halo assembly time at high redshift.« less
Authors:
;  [1] ;  [2] ; ;  [3] ; ;  [4] ;  [5] ;  [6] ;  [7] ;  [8]
  1. School of Physics, University of Melbourne, Parkville, Vic 3010 (Australia)
  2. Kavli Institute for Cosmology and Institute of Astronomy, University of Cambridge, Cambridge (United Kingdom)
  3. Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands)
  4. UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States)
  5. Institute for Astronomy, ETH Zurich, 8092 Zurich (Switzerland)
  6. Department of Radiology, Mayo Clinic, Rochester, MN 55905 (United States)
  7. Space Telescope Science Institute, Baltimore, MD 21218 (United States)
  8. Department of Astronomy, Yale University, New Haven, CT 06520 (United States)
Publication Date:
OSTI Identifier:
22365041
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; 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; ANGULAR CORRELATION; CATALOGS; COMPARATIVE EVALUATIONS; COSMOLOGY; GALAXIES; LUMINOSITY; MASS; NONLUMINOUS MATTER; RED SHIFT; SENSITIVITY; SPACE; STAR EVOLUTION; TELESCOPES; VISIBLE RADIATION