Testing Einstein’s Equivalence Principle and Its Cosmological Evolution from Quasar Gravitational Redshifts

  title={Testing Einstein’s Equivalence Principle and Its Cosmological Evolution from Quasar Gravitational Redshifts},
  author={Evencio Mediavilla and J. Jim'enez-Vicente},
  journal={The Astrophysical Journal},
We propose and apply a new test of Einstein’s equivalence principle (EEP) based on the gravitational redshift induced by the central supermassive black hole of quasars in the surrounding accretion disk. Specifically, we compare the observed gravitational redshift of the Fe III λ λ 2039-2113 emission line blend in quasars with the predicted values in a wide, uncharted, cosmic territory (0 ≲ z cosm ≲ 3). For the first time we measure, with statistical uncertainties comparable or better than those… 

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