Gamma-Ray Bursts and the Early Star-Formation History

Abstract

We review the uncertainties in high-z star-formation rate (SFR) measures and the constraints that one obtains from high-z gamma-ray burst (GRB) rates on them. We show that at the present time, the GRB rates per unit star-formation at z > 3 are higher than at lower redshift. There could be a multitude of reasons for this: a stellar metallicity bias for GRB production, a top-heavy initial mass function (IMF) and/or missing a significant fraction of star-formation in field galaxy surveys due to incompleteness, surface brightness limitations and cosmic variance. We also compare metallicity predictions made using a hierarchical model of cosmic chemical evolution based on two recently proposed SFRs, one based on the observed galaxy luminosity function at high redshift and one based on the GRB rate and find that within the considerable scatter in metal abundance measures, they both are consistent with the data. Analyzing the ensemble of different measurements together, we conclude that despite metallicity biases, GRBs may be a less biased probe of star-formation at z > 3 than at z < 2. There is likely to be a common origin to the high GRB rate per unit star-formation and the high observed Lyman-continuum production rate in high redshift galaxies and that this may be due to a relative overabundance of stars with mass >25 M ⊙ which are likely GRB progenitors. We also find that to reconcile these measurements with the Thomson scattering

The Dawes Review 8: Measuring the Stellar Initial Mass Function

“…Behroozi & Silk (2015) used the updated SFH normalisation from Behroozi et al (2013) to scale down the GRB-inferred SFH of Kistler et al (2013) at z > 4, making them more consistent with their inferred SFH fit. In a recent review, though, Chary et al (2016) show that metallicity constraints at z > 2 from damped Lyα systems are consistent with the rather more elevated SFH inferred by Kistler et al (2013), and consistent with that of Gruppioni et al (2013) and Rowan-Robinson et al (2016) than the lower SFH of Behroozi & Silk (2015). It is noteworthy in this discussion that the radio luminosity function results of Novak et al (2017) are also consistent with the GRB-inferred SFR densities (Chary, Berger, & Cowie 2007;Yüksel et al 2008;Kistler et al 2009Kistler et al , 2013 at these high redshifts, reinforcing the expectation of a steepening low luminosity tail to the high redshift galaxy luminosity function (Kistler et al 2013;Bouwens et al 2015a).…”

Gamma-ray bursts and their use as cosmic probes

“…In this section, I provide an overview of our current understanding of the environments traced by GRBs, and of the selection effects to be aware of in a GRB-selected galaxy sample. For a more detailed and very comprehensive review on the use of GRBs to study the cosmic SFR density, I redirect the reader to [187].…”

The Consequences of Gamma-ray Burst Jet Opening Angle Evolution on the Inferred Star Formation Rate

“…Because long gamma-ray bursts (lGRBs) are the most luminous explosions in the universe and because of definitive E-mail: lloyd-ronning@lanl.gov evidence of their association with massive star progenitors (Galama et al 1998;Hjorth et al 2003;Woosley & Bloom 2006;Hjorth & Bloom 2012), they have long been suggested as tools with which to estimate the high redshift star formation rate (Lloyd-Ronning et al 2002;Jakobsson et al 2005;Kistler et al 2008;Yüksel et al 2008;Kistler et al 2009;Wanderman & Piran 2010;Robertson & Ellis 2012;Trenti et al 2013;Lien et al 2014;Petrosian et al 2015;Chary et al 2016;Kinugawa et al 2019). However, there are a number of issues that make doing so difficult, essentially related to understanding exactly what types of stars and/or fractions of the global stellar population produce GRBs (including accounting for multiple GRB progenitors), and understanding how this relationship may change over cosmic time.…”