TY - JOUR
T1 - Model selection based on the angular-diameter distance to the compact structure in radio quasars
AU - Melia, F.
N1 - Funding Information:
I am very grateful to the anonymous referee, who has provided many suggestions for improving the presentation in this paper. I am also grateful to Amherst College for its support through a John Woodruff Simpson Lectureship, and to Purple Mountain Observatory in Nanjing, China, for its hospitality while part of this work was being carried out. This work was partially supported by grant 2012T1J0011 from The Chinese Academy of Sciences Visiting Professorships for Senior International Scientists, and grant GDJ20120491013 from the Chinese State Administration of Foreign Experts Affairs.
Publisher Copyright:
© 2018, EPLA.
PY - 2018/8
Y1 - 2018/8
N2 - Of all the distance and temporal measures in cosmology, the angular-diameter distance, d A(z), uniquely reaches a maximum value at some finite redshift and then decreases to zero towards the Big Bang. This effect has been difficult to observe due to a lack of reliable, standard rulers, though refinements to the identification of the compact structure in radio quasars may have overcome this deficiency. In this letter, we assemble a catalog of 140 such sources with 0 ≲ z ≲ 3 for model selection and the measurement of zmax. In flat ΛCDM, we find that ωm = 0.24-0.09 +0.1, fully consistent with the Planck optimized value, with zmax = 1.69. Both of these values are associated with a d A(z) indistinguishable from that predicted by the zero active mass condition, p + 3p = 0, in terms of the total pressure p and total energy density ρ of the cosmic fluid. An expansion driven by this constraint, known as the Rh = ct universe, has zmax = 1.178, which differs from the ΛCDM optimized value by less than ∼ 1.6%. Indeed, the Bayes Information Criterion favours Rh = ct over flat ΛCDM with a likelihood of ∼ 81% vs. 19%, suggesting that the optimized parameters in Planck ΛCDM mimic the constraint p = -p/3.
AB - Of all the distance and temporal measures in cosmology, the angular-diameter distance, d A(z), uniquely reaches a maximum value at some finite redshift and then decreases to zero towards the Big Bang. This effect has been difficult to observe due to a lack of reliable, standard rulers, though refinements to the identification of the compact structure in radio quasars may have overcome this deficiency. In this letter, we assemble a catalog of 140 such sources with 0 ≲ z ≲ 3 for model selection and the measurement of zmax. In flat ΛCDM, we find that ωm = 0.24-0.09 +0.1, fully consistent with the Planck optimized value, with zmax = 1.69. Both of these values are associated with a d A(z) indistinguishable from that predicted by the zero active mass condition, p + 3p = 0, in terms of the total pressure p and total energy density ρ of the cosmic fluid. An expansion driven by this constraint, known as the Rh = ct universe, has zmax = 1.178, which differs from the ΛCDM optimized value by less than ∼ 1.6%. Indeed, the Bayes Information Criterion favours Rh = ct over flat ΛCDM with a likelihood of ∼ 81% vs. 19%, suggesting that the optimized parameters in Planck ΛCDM mimic the constraint p = -p/3.
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U2 - 10.1209/0295-5075/123/39001
DO - 10.1209/0295-5075/123/39001
M3 - Article
AN - SCOPUS:85054027894
SN - 0295-5075
VL - 123
JO - EPL
JF - EPL
IS - 3
M1 - 39001
ER -