TY - JOUR
T1 - Model-independent Test of the Cosmic Distance Duality Relation
AU - Ruan, Cheng Zong
AU - Melia, Fulvio
AU - Zhang, Tong Jie
N1 - Funding Information:
We are grateful to the anonymous referee for recommending several improvements to this manuscript. This work was supported by the National Key R & D Program of China (2017YFA0402600), the National Science Foundation of China (Grants No. 11573006, 11528306), the Fundamental Research Funds for the Central Universities and the Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund (the second phase).
Publisher Copyright:
© 2018. The American Astronomical Society. All rights reserved.
PY - 2018/10/10
Y1 - 2018/10/10
N2 - A validation of the cosmic distance duality (CDD) relation, , 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 H ii galaxy Hubble diagram using Gaussian processes, to confirm the validity of the CDD at a very high level of confidence. Using parameterizations and , our best-fit results are , and and , 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.
AB - A validation of the cosmic distance duality (CDD) relation, , 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 H ii galaxy Hubble diagram using Gaussian processes, to confirm the validity of the CDD at a very high level of confidence. Using parameterizations and , our best-fit results are , and and , 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.
KW - cosmological parameters
KW - cosmology: observations
KW - distance scale
KW - galaxies: active
KW - gravitational lensing: strong
UR - http://www.scopus.com/inward/record.url?scp=85055189013&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85055189013&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/aaddfd
DO - 10.3847/1538-4357/aaddfd
M3 - Article
AN - SCOPUS:85055189013
VL - 866
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1
M1 - 31
ER -