Constraining the cosmic equation of state from old galaxies at high redshift
/ Authors
/ Abstract
New limits on the cosmic equation of state are derived from age measurements of three recently reported old high-redshift galaxies (OHRG). The results are based on a flat Friedmann–Robertson–Walker (FRW) type cosmological model driven by non-relativistic matter plus a smooth component parametrized by its equation of state pxωρx (ω−1). The range of ω is strongly dependent on the matter density parameter. For ΩM∼0.3, as indicated from dynamical measurements, the age estimates of the OHRG restrict the cosmic parameter to ω−0.27. However, if ΩM is the one suggested by some studies of field galaxies, i.e., ΩM≃0.5, only a cosmological constant (ω=−1) may be compatible with these data.
Journal: Monthly Notices of the Royal Astronomical Society