The most massive Population III stars

Abstract

ABSTRACT Recent data from the JWST suggest that there are realistic prospects for detecting the earliest generation of stars at redshift ∼20. These metal-poor, gaseous Population III (Pop III) stars are likely in the mass range $10\!-\!10^3\, {\rm M}_{\odot }$ . We develop a framework for calculating the abundances of Pop III stars as well as the distribution of the most massive Pop III stars based on an application of extreme-value statistics. Our calculations use the star formation rate density from a recent simulation to calibrate the star formation efficiency from which the Pop III stellar abundances are derived. Our extreme-value modelling suggests that the most massive Pop III stars at redshifts 10 < z < 20 are likely to be $\gtrsim 10^3\!-\!10^4\, {\rm M}_\odot$ . Such extreme Pop III stars were sufficiently numerous to be the seeds of supermassive black holes at high redshifts and possibly source detectable gravitational waves. We conclude that the extreme-value formalism provides an effective way to constrain the stellar initial mass function.