Normalization of the Matter Power Spectrum via the Ellipticity Function of Giant Galaxy Voids from SDSS DR5

TL;DR

This paper measures the ellipticity function of giant galaxy voids from SDSS DR5 to normalize the matter power spectrum, incorporating observational data and modeling effects like redshift distortion and galaxy bias.

Contribution

It introduces an observational method to normalize the matter power spectrum using void ellipticity functions, accounting for observational effects and fitting to data.

Findings

Best-fit sigma_8 = 0.90 ± 0.04

Result is higher than WMAP value but aligns with recent CMB analyses

Provides a new approach to matter power spectrum normalization

Abstract

The ellipticity function of cosmic voids exhibits strong dependence on the amplitude of the linear matter power spectrum. Analyzing the most recent void catalogs constructed by Foster and Nelson from the fifth data release of the Sloan Digital Sky Survey, we measure observationally the ellipticity function of giant galaxy voids. Then, we incorporate the redshift distortion and galaxy bias effect into the analytic model of the void ellipticity function and fit it to the observational result by adjusting the value of the power-spectrum normalization with the help of the generalized chi^{2}-minimization method. The best-fit normalization of the linear power spectrum is found to be sigma_{8}=0.90+/-0.04. Our result is higher than the WMAP sigma_{8}-value but consistent with that from the recent work of Liu and Li who have constructed a new improved CMB map independently.