Semi-analytic modelling of Pop. III star formation and metallicity evolution -- II. Impact on 21cm power spectrum

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Hauptverfasser: Ventura, Emanuele M., Qin, Yuxiang, Balu, Sreedhar, Wyithe, J. Stuart B.
Format: Preprint
Veröffentlicht: 2025
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author Ventura, Emanuele M.
Qin, Yuxiang
Balu, Sreedhar
Wyithe, J. Stuart B.
author_facet Ventura, Emanuele M.
Qin, Yuxiang
Balu, Sreedhar
Wyithe, J. Stuart B.
contents Simulating Population (Pop.) III star formation in mini-halos in a large cosmological simulation is an extremely challenging task but it is crucial to estimate its impact on the 21cm power spectrum. In this work, we develop a framework within the semi-analytical code meraxes to estimate the radiative backgrounds from Pop. III stars needed for the computation of the 21cm signal. We computed the 21cm global signal and power spectrum for different Pop. III models varying star formation efficiency, initial mass function (IMF) and specific X-ray luminosity per unit of star formation (LX/SFR). In all the models considered, we find Pop. III stars have little to no impact on the reionization history but significantly affect the thermal state of the intergalactic medium (IGM) due to the strong injection of X-ray photons from their remnants that heat the neutral IGM at $z \geq$ 15. This is reflected not only on the 21cm sky-averaged global signal during the Cosmic Dawn but also on the 21cm power spectrum at $z \leq$ 10 where models with strong Pop. III X-ray emission have larger power than models with no or mild Pop. III X-ray emission. We estimate observational uncertainties on the power spectrum using 21cmsense and find that models where Pop. III stars have a stronger X-ray emission than Pop. II are distinguishable from models with no or mild Pop. III X-ray emission with 1000 hours observations of the upcoming SKA1-low.
format Preprint
id arxiv_https___arxiv_org_abs_2502_08971
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Semi-analytic modelling of Pop. III star formation and metallicity evolution -- II. Impact on 21cm power spectrum
Ventura, Emanuele M.
Qin, Yuxiang
Balu, Sreedhar
Wyithe, J. Stuart B.
Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
Simulating Population (Pop.) III star formation in mini-halos in a large cosmological simulation is an extremely challenging task but it is crucial to estimate its impact on the 21cm power spectrum. In this work, we develop a framework within the semi-analytical code meraxes to estimate the radiative backgrounds from Pop. III stars needed for the computation of the 21cm signal. We computed the 21cm global signal and power spectrum for different Pop. III models varying star formation efficiency, initial mass function (IMF) and specific X-ray luminosity per unit of star formation (LX/SFR). In all the models considered, we find Pop. III stars have little to no impact on the reionization history but significantly affect the thermal state of the intergalactic medium (IGM) due to the strong injection of X-ray photons from their remnants that heat the neutral IGM at $z \geq$ 15. This is reflected not only on the 21cm sky-averaged global signal during the Cosmic Dawn but also on the 21cm power spectrum at $z \leq$ 10 where models with strong Pop. III X-ray emission have larger power than models with no or mild Pop. III X-ray emission. We estimate observational uncertainties on the power spectrum using 21cmsense and find that models where Pop. III stars have a stronger X-ray emission than Pop. II are distinguishable from models with no or mild Pop. III X-ray emission with 1000 hours observations of the upcoming SKA1-low.
title Semi-analytic modelling of Pop. III star formation and metallicity evolution -- II. Impact on 21cm power spectrum
topic Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2502.08971