Constraints on Primordial Power Spectrum from Galaxy Luminosity Functions

TL;DR

This paper uses high-redshift galaxy UV luminosity functions to place new constraints on the primordial power spectrum, especially on small scales, by analyzing the connection between galaxy observations and underlying cosmological fluctuations.

Contribution

It is the first to derive constraints on the primordial power spectrum from galaxy UV luminosity functions at high redshifts, linking galaxy data to primordial fluctuations on small scales.

Findings

Constraints on primordial power spectrum on scales of k ~ 10-10^3 Mpc^{-1}

Demonstrates how cosmological assumptions influence astrophysical parameter estimates

Provides a novel method to probe small-scale primordial fluctuations using galaxy luminosity functions

Abstract

We derive constraints on primordial power spectrum, for the first time, from galaxy UV luminosity functions (LFs) at high redshifts. Since the galaxy LFs reflect an underlying halo mass function which depends on primordial fluctuations, one can constrain primordial power spectrum, particularly on small scales. We perform a Markov Chain Monte Carlo analysis by varying parameters for primordial power spectrum as well as those describing astrophysics. We adopt the UV LFs derived from Hubble Frontier Fields data at $z = 6 -10$, which enable us to probe primordial fluctuations on the scales of $k \sim 10 - 10^3~{\rm Mpc}^{-1}$. Our analysis also clarifies how the assumption on cosmology such as primordial power spectrum affects the determination of astrophysical parameters.