Constraints on cosmological parameters in power-law cosmology

TL;DR

This paper assesses observational constraints on power-law cosmology using current and simulated data, comparing results with $ ext{Lambda}$CDM, and finds it fits some data sets but not others, with future data potentially conflicting.

Contribution

It provides updated constraints on power-law cosmology parameters using recent observational data and forecasts future constraints, highlighting its limitations compared to $ ext{Lambda}$CDM.

Findings

Power-law cosmology fits Union2.1 data well but not H(z) data.

Future JDEM-like data constraints are inconsistent with current data.

Power-law models approach $ ext{Lambda}$CDM as $q o -1$.

Abstract

In this paper, we examine observational constraints on the power law cosmology; essentially dependent on two parameters $H_0$ (Hubble constant) and $q$ (deceleration parameter). We investigate the constraints on these parameters using the latest 28 points of H(z) data and 580 points of Union2.1 compilation data and, compare the results with the results of $\Lambda$CDM. We also forecast constraints using a simulated data set for the future JDEM, supernovae survey. Our studies give better insight into power law cosmology than the earlier done analysis by Kumar [arXiv:1109.6924] indicating it tuning well with Union2.1 compilation data but not with H(z) data. However, the constraints obtained on $<H_0>$ and $<q>$ i.e. $H_0$ average and $q$ average using the simulated data set for the future JDEM, supernovae survey are found to be inconsistent with the values obtained from the H(z) and Union2.1 compilation data. We also perform the statefinder analysis and find that the power-law cosmological models approach the standard $\Lambda$CDM model as $q\rightarrow -1$. Finally, we observe that although the power law cosmology explains several prominent features of evolution of the Universe, it fails in details.