Model-independent Test of the Cosmic Distance Duality Relation
| Autor: | Tong-Jie Zhang, Fulvio Melia, Cheng Zong Ruan |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Physics
COSMIC cancer database Cosmology and Nongalactic Astrophysics (astro-ph.CO) 010308 nuclear & particles physics Computation FOS: Physical sciences Astronomy and Astrophysics General Relativity and Quantum Cosmology (gr-qc) Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences Astrophysics - Astrophysics of Galaxies Duality relation General Relativity and Quantum Cosmology Test (assessment) High Energy Physics - Phenomenology High Energy Physics - Phenomenology (hep-ph) Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences Applied research China 010303 astronomy & astrophysics Mathematical economics Astrophysics - Cosmology and Nongalactic Astrophysics |
| Popis: | A validation of the cosmic distance duality (CDD) relation, eta(z)=(1+z)^2 d_A(z)/d_L(z)=1, coupling the luminosity (d_L) and angular-diameter (d_A) distances, is crucial because its violation would require exotic new physics. We present a model-independent test of the CDD, based on strong lensing and a reconstruction of the HII galaxy Hubble diagram using Gaussian Processes, to confirm the validity of the CDD at a very high level of confidence. Using parameterizations eta(z) = 1 + eta_0 z and eta(z) = 1 + eta_1 z + eta_2 z^2, our best-fit results are eta_0 = 0.0147^{+0.056}_{-0.066}, and eta_1 = 0.1091^{+0.1680}_{-0.1568} and eta_2 = -0.0603^{+0.0999}_{-0.0988}, respectively. In spite of these strong constraints, however, we also point out that the analysis of strong lensing using a simplified single isothermal sphere (SIS) model for the lens produces some irreducible scatter in the inferred CDD data. The use of an extended SIS approximation, with a power-law density structure, yields very similar results, but does not lessen the scatter due to its larger number of free parameters, which weakens the best-fit constraints. Future work with these strong lenses should therefore be based on more detailed ray-tracing calculations to determine the mass distribution more precisely. 10 pages, 6 figures, 1 table. Accepted for publication in ApJ |
| Databáze: | OpenAIRE |
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