A roadmap to gamma-ray bursts: new developments and applications to cosmology

TL;DR

This paper reviews gamma-ray bursts, their classifications, origins, and potential as cosmological tools, emphasizing recent developments, correlations, and statistical methods to improve their use as standard candles.

Contribution

It provides a comprehensive overview of gamma-ray burst classifications, progenitors, and their applications to cosmology, including new calibration techniques and recent statistical analyses.

Findings

Gamma-ray bursts can serve as standard candles under certain conditions.

Calibration techniques improve the reliability of gamma-ray burst correlations.

Recent statistical methods constrain gamma-ray burst applications in high-redshift cosmology.

Abstract

Gamma-ray bursts are the most powerful explosions in the universe and are mainly placed at very large redshifts, up to $z\simeq 9$. In this short review, we first discuss gamma-ray burst classification and morphological properties. We then report the likely relations between gamma-ray bursts and other astronomical objects, such as black holes, supernovae, neutron stars, etc., discussing in detail gamma-ray burst progenitors. We classify long and short gamma-ray bursts, working out their timescales, and introduce the standard fireball model. Afterwards, we focus on direct applications of gamma-ray bursts to cosmology and underline under which conditions such sources would act as perfect standard candles if correlations between photometric and spectroscopic properties were not jeopardized by the \emph{circularity problem}. In this respect, we underline how the shortage of low-$z$ gamma-ray bursts prevents anchor gamma-ray bursts with primary distance indicators. Moreover, we analyze in detail the most adopted gamma-ray burst correlations, highlighting their main differences. We therefore show calibration techniques, comparing such treatments with non-calibration scenarios. For completeness, we discuss the physical properties of the correlation scatters and systematics occurring during experimental computations. Finally, we develop the most recent statistical methods, star formation rate and high-redshift gamma-ray burst excess and show the most recent constraints got from experimental analyses.