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Title: A 3% DETERMINATION OF H {sub 0} AT INTERMEDIATE REDSHIFTS

Recent determinations of the Hubble constant, H {sub 0}, at extremely low and very high redshifts based on the cosmic distance ladder (grounded with trigonometric parallaxes) and a cosmological model (applied to Planck 2013 data), respectively, are revealing an intriguing discrepancy (nearly 9% or 2.4σ) that is challenging astronomers and theoretical cosmologists. In order to shed some light on this problem, here we discuss a new determination of H {sub 0} at intermediate redshifts (z ∼ 1), using the following four cosmic probes: (1) measurements of the angular diameter distances for galaxy clusters based on the combination of the Sunyaev-Zeldovich effect and X-ray data (0.14 ≤ z ≤ 0.89); (2) the inferred ages of old high redshift galaxies (0.62 ≤ z ≤ 1.70); (3) measurements of the Hubble parameter H(z) (0.1 ≤ z ≤ 1.8); and (4) the baryon acoustic oscillation signature (z = 0.35). In our analysis, assuming a flat ΛCDM cosmology and considering statistical plus systematic errors, we obtain H{sub 0}=74.1{sub −2.2}{sup +2.2} km s{sup –1} Mpc{sup –1} (1σ) which is a 3% determination of the Hubble constant at intermediate redshifts. We stress that each individual test adopted here has error bars larger than the ones appearing in the calibration ofmore » the extragalactic distance ladder. However, the remarkable complementarity among the four tests works efficiently in greatly reducing the possible degeneracy on the space parameter (Ω {sub m}, h), ultimately providing a value of H {sub 0} that is in excellent agreement with the determination using recessional velocities and distances to nearby objects.« less
Authors:
 [1] ;  [2]
  1. Departamento de Astronomia, Universidade de São Paulo, 05508-900 São Paulo, SP (Brazil)
  2. Faculdade de Física, Universidade Federal do Pará, 66075-110, Belém, PA (Brazil)
Publication Date:
OSTI Identifier:
22364007
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 781; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BARYONS; CALIBRATION; COSMOLOGICAL MODELS; COSMOLOGY; DISTANCE; GALAXIES; GALAXY CLUSTERS; OSCILLATIONS; PROBES; RED SHIFT; SPACE; VELOCITY; VISIBLE RADIATION; X RADIATION