Dynamical curvature in a nonstandard cosmological model
Abstract
We consider a nonrelativistic cosmological model introduced in [1] and derived as the nonrelativistic limit (or approximation at subHubble scales) of a general relativistic model in [3, 4]. The latter is defined by an energymomentum tensor containing only dust and a nontrivial energy flow. The nonrelativistic limit contains in leading order a 1storder relativistic contribution to the spatial curvature whose timedependence drives the accelerated expansion of the Universe (we do not need any kind of dark energy). Analytic solutions of the model are fixed by three constants (initial conditions). In the present paper we use our model as a toy model by adjusting the three constants in two different ways to a second order polynomial fit by Montenari and Räsänen [5] to the observed expansion rate $H(z)$ for $z \lesssim 2$ (mainly cosmic chronometer data). In scenario 1 we adjust our model to this fit and its derivative at the selfconsistently determined transition redshift $z_t$. In scenario 2 we use the same fit at $z_t$ and in addition $H(z)$ at decoupling $(z = 1089)$. The Hubble parameter $H_0$ is taken from the polynomial fit in [5]: $H_0 = 64.2 km/s/Mpc$. For both scenarios we obtain a satisfactory agreement between predicted and observed $H(z)$ values. But the outcomes for the curvature function $k(z)$ are completely different: In scenario 1 we obtain a strong variation of $k(z)$ ranging from $k(0) =  1.216$ up to $k(2.33) = 0.718$. On the other hand scenario 2 shows an almost constant value for $k(z) \sim  1$ for all $z \lesssim 2$ in agreement with the polynomial fit to one of the FRW consistency conditions performed in [5].
 Publication:

arXiv eprints
 Pub Date:
 December 2017
 DOI:
 10.48550/arXiv.1712.03124
 arXiv:
 arXiv:1712.03124
 Bibcode:
 2017arXiv171203124S
 Keywords:

 Physics  General Physics
 EPrint:
 8 pages