Searching for Pop III stars and galaxies at high redshift

TL;DR

This paper reviews the properties and observational signatures of Population III stars and galaxies at high redshift, critically examines existing claims, and discusses ongoing and future searches for these primordial objects.

Contribution

It provides a comprehensive overview of expected signatures of Pop III stars, evaluates past claims, and summarizes future observational efforts at z>6.

Findings

Lyman-alpha and HeII 1640 lines are key signatures of Pop III objects.

Existing claims of Pop III detection are critically assessed.

Future deep observations aim to detect sources of cosmic reionisation.

Abstract

We review the expected properties of Pop III and very metal-poor starburst and the behaviour the Lyman-alpha and HeII 1640 emission lines, which are most likely the best/easiest signatures to single out such objects. Existing claims of Pop III signatures in distant galaxies are critically examined, and the searches for HeII 1640 emission at high redshift are summarised. Finally, we briefly summarise ongoing and future deep observations at z>6 aiming in particular at detecting the sources of cosmic reionisation as well as primeval/Pop III galaxies.