Large-scale structure and the Cardassian fluid

TL;DR

This paper tests the power law Cardassian model against SDSS galaxy data, finding it only fits under unusual parameters and is indistinguishable from LCDM when using standard cosmological constants.

Contribution

It provides a critical comparison of the power law Cardassian model with observational data, highlighting its limitations and equivalence to LCDM under typical parameters.

Findings

Fits only for unusual cosmological parameters

Best-fit models are phantom models

Indistinguishable from LCDM with standard constants

Abstract

In this paper, we confront the predictions of the power law cardassian model for the baryon power spectrum with the observations of the SDSS galaxy survey. We show that they fit only for very unusual values of the cold dark matter or baryon density parameters, the Hubble parameter or the spectral index of the initial power spectrum. Moreover, the best-fit Cardassian models turn out to be phantom models. If one wants to recover the usual values for these constants, as quoted by the WMAP team, the power law Cardassian model turns out to be indistinguishable from a LCDM model.