Open AccessThe distance–redshift equation in quintessence cosmology and the estimation of H 0 through time delays
Author(s) -
Giovi Fabio,
Amendola Luca
Publication year - 2001
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2001.04531.x
Subject(s) - quintessence , physics , redshift , equation of state , dark energy , cosmology , astrophysics , cosmological constant , hubble's law , mathematical physics , quantum mechanics , galaxy
We calculate analytically and numerically the distance–redshift equation in perfect fluid quintessence models and give an accurate fit to the numerical solutions for all the values of the density parameter and the quintessence equation of state. Then we apply our solutions to the estimation of H 0 from multiple image time delays and find that the inclusion of quintessence modifies significantly the likelihood distribution of H 0 , generally reducing the best estimate with respect to a pure cosmological constant. Marginalizing over the other parameters (Ω m and the quintessence equation of state) we obtain H 0 =71±6 km s −1 Mpc −1 for an empty beam and H 0 =64±4 km s −1 Mpc −1 for a filled beam. These errors, however, do not take into account the uncertainty on the modelling of the lens. We also discuss the future prospects for distinguishing quintessence from a cosmological constant with time delays.