Testing Bump in the Cosmological Power Spectrum Using Dwarf Galaxies

TL;DR

This study investigates how dwarf galaxy observations can constrain deviations in the cosmological power spectrum, specifically testing for a 'bump' feature at 1.3 Mpc, and finds observational limits on its amplitude.

Contribution

It introduces a method to use dwarf galaxy data to constrain specific features in the cosmological power spectrum, focusing on a bump at 1.3 Mpc.

Findings

Bump in power spectrum increases dwarf galaxy luminosity function at certain magnitudes.

Observational data constrains bump amplitude to less than 0.25 at 3-sigma.

Bump effects are detectable only at specific dwarf galaxy luminosities.

Abstract

We analyze the possibility of using observational data on nearby dwarf galaxies -- their luminosity functions and spatial distributions -- to constrain deviations of the cosmological power spectrum from the standard one. Specifically, we consider a cosmological model with a "bump" in the power spectrum at a wavelength of 1.3~Mpc and a dimensionless amplitude $\mathcal{A}=2.0$. Such a spectrum is motivated by observations of an excess number of galaxies at high redshifts. The bump leads to a noticeable increase in the luminosity function in the range $-13 > M_B > -17$ at $z=0$. Comparison with observations constrains the bump amplitude to $\mathcal{A} < 0.25$ at a 3-sigma significance level for a wavelength of 1.3~Mpc. For wavelengths smaller than 0.8~Mpc, the bump manifests only in the luminosity function of dwarfs with $M_B > -14$.