Gamma-ray burst cosmology: Hubble diagram and star formation history

TL;DR

This paper explores the use of gamma-ray bursts as tools for measuring the universe's expansion and star formation history at high redshifts, offering an alternative to supernovae observations.

Contribution

It introduces methods to utilize GRBs for constructing the Hubble diagram and constraining star formation in dark matter halos, especially at high redshifts.

Findings

GRBs can extend the Hubble diagram beyond supernova limits.

GRB data can constrain the minimum dark matter halo mass for star formation.

A detailed approach to measure high-z star formation rate using GRBs.

Abstract

We briefly introduce the disadvantages for Type Ia supernovae (SNe Ia) as standard candles to measure the Universe, and suggest Gamma-ray bursts (GRBs) can serve as a powerful tool for probing the properties of high redshift Universe. We use GRBs as distance indicators in constructing the Hubble diagram at redshifts beyond the current reach of SNe Ia observations. Since the progenitors of long GRBs are confirmed to be massive stars, they are deemed as an effective approach to study the cosmic star formation rate (SFR). A detailed representation of how to measure high-$z$ SFR using GRBs is presented. Moreover, first stars can form only in structures that are suitably dense, which can be parameterized by defining the minimum dark matter halo mass $M_{\rm min}$. $M_{\rm min}$ must play a crucial role in star formation. The association of long GRBs with the collapses of massive stars also indicates that the GRB data can be applied to constrain the minimum halo mass $M_{\rm min}$ and to investigate star formation in dark matter halos.