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SUMMARY:Testing the Cosmological Principle - Subir Sarkar (University of O
 xford)
DTSTART:20210310T141500Z
DTEND:20210310T151500Z
UID:TALK157954@talks.cam.ac.uk
CONTACT:Scott Melville
DESCRIPTION:In the ΛCDM cosmological model it is assumed that the univers
 e is statistically isotropic and homogeneous when averaged on scales >100 
 Mpc. That the CMB has a large dipole anisotropy is explained as due to our
  'peculiar motion' because of local inhomogeneity. There should then be a 
 similar dipole in the sky distribution of high redshift sources. Using a c
 atalogue of 1.4 million quasars we find this standard expectation is rejec
 ted at 4.9σ.\nThis calls into question the usual practice of boosting to 
 the 'CMB frame' to analyse cosmological data. In the heliocentric frame th
 e acceleration of the Hubble expansion rate is also a dipole (at 3.9σ) al
 igned with the CMB. It can no longer be argued that boosting to the CMB fr
 ame makes this acceleration look isotropic\, so it can be interpreted as d
 ue to Λ.
LOCATION:ONLINE - Details to be sent by email
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