TY - JOUR
T1 - The AGN Hubble Diagram and its implications for cosmology
AU - Melia, F.
N1 - Funding Information:
I am grateful to the anonymous referee for very helpful comments that have led to an improvement in the manuscript. 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:
© 2015, Springer Science+Business Media Dordrecht.
PY - 2015/9/22
Y1 - 2015/9/22
N2 - We use a recently proposed luminosity distance measure for relatively nearby active galactic nuclei (AGNs) to test the predicted expansion of the Universe in the Rh=ct$R_{\mathrm{h}}=ct$ and ΛCDM$\varLambda\mathrm{CDM}$ cosmologies. This comparative study is particularly relevant to the question of whether or not the Universe underwent a transition from decelerated to accelerated expansion, which is believed to have occurred—on the basis of Type Ia SN studies—within the redshift range (0≲z≲1.3$0\lesssim z\lesssim 1.3$) that will eventually be sampled by these objects. We find that the AGN Hubble Diagram constructed from currently available sources does not support the existence of such a transition. While the scatter in the AGN data is still too large for any firm conclusions to be drawn, the results reported here nonetheless somewhat strengthen similar results of comparative analyses using other types of source. We show that the Akaike, Kullback, and Bayes Information Criteria all consistently yield a likelihood of ∼84–96%$\sim 84\mbox{--}96~\%$ that Rh=ct$R_{\mathrm{h}}=ct$ is closer to the “true” cosmology than ΛCDM$\varLambda\mathrm{CDM}$ is, though neither model adequately accounts for the data, suggesting an unnaccounted-for source of scatter.
AB - We use a recently proposed luminosity distance measure for relatively nearby active galactic nuclei (AGNs) to test the predicted expansion of the Universe in the Rh=ct$R_{\mathrm{h}}=ct$ and ΛCDM$\varLambda\mathrm{CDM}$ cosmologies. This comparative study is particularly relevant to the question of whether or not the Universe underwent a transition from decelerated to accelerated expansion, which is believed to have occurred—on the basis of Type Ia SN studies—within the redshift range (0≲z≲1.3$0\lesssim z\lesssim 1.3$) that will eventually be sampled by these objects. We find that the AGN Hubble Diagram constructed from currently available sources does not support the existence of such a transition. While the scatter in the AGN data is still too large for any firm conclusions to be drawn, the results reported here nonetheless somewhat strengthen similar results of comparative analyses using other types of source. We show that the Akaike, Kullback, and Bayes Information Criteria all consistently yield a likelihood of ∼84–96%$\sim 84\mbox{--}96~\%$ that Rh=ct$R_{\mathrm{h}}=ct$ is closer to the “true” cosmology than ΛCDM$\varLambda\mathrm{CDM}$ is, though neither model adequately accounts for the data, suggesting an unnaccounted-for source of scatter.
KW - Active galactic nuclei
KW - Cosmological parameters
KW - Cosmology: observations
KW - Cosmology: redshift
KW - Cosmology: theory
KW - Gravitation
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U2 - 10.1007/s10509-015-2483-4
DO - 10.1007/s10509-015-2483-4
M3 - Article
AN - SCOPUS:84939631219
VL - 359
JO - Astrophysics and Space Science
JF - Astrophysics and Space Science
SN - 0004-640X
IS - 1
M1 - 34
ER -