Open AccessDetermining the equation of state of the expanding Universe: inverse problem in cosmology
Author(s) -
Nakamura Takashi,
Chiba Takeshi
Publication year - 1999
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.1365-8711.1999.02551.x
Subject(s) - physics , hubble's law , redshift , equation of state , universe , cosmology , luminosity distance , quasar , de sitter universe , hubble volume , astrophysics , big rip , flatness problem , age of the universe , metric expansion of space , dark energy , theoretical physics , mathematical physics , quantum mechanics , galaxy
Even if the luminosity distance as a function of redshift is obtained accurately using, for example, Type Ia supernovae, the equation of state of the Universe cannot be determined uniquely, as it depends on one free parameter Ο k 0 = k /( a 0 2 H 0 2 ), where a 0 and H 0 are the present scalefactor and the Hubble parameter, respectively. This degeneracy might be resolved if, for example, the time variations of the redshift of quasars are measured as proposed recently by Loeb. Therefore, the equation of state of the Universe (or the metric of the Universe) might be determined in future without any theoretical assumption on the matter content of the Universe.