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A Comparison of Modeling Approaches for the Cosmic Abundance of the First Stars and Galaxies

Presentation #202.08 in the session Cosmology — iPoster Session.

Published onJun 29, 2022
A Comparison of Modeling Approaches for the Cosmic Abundance of the First Stars and Galaxies

Population III (Pop III) stars are the theorized first stars formed from the primordial gas following the Big Bang. Simulations suggest that these stars may have masses much larger than those formed from metal-enriched gas, but observations remain elusive. Upcoming data such as radio observations of the 21 cm line of Hydrogen will have the ability to detect Pop III stars through their impact on intergalactic gas, but improved theoretical predictions are required to guide and interpret them. Cosmological hydrodynamical simulations can follow detailed 3D physics with high fidelity, but they are computationally expensive and thus cannot simulate the large volumes needed to predict the global abundance of the first stars and galaxies. A promising solution to this challenge lies within semi-analytic and analytic models that are much more computationally efficient. A variety of models have been used in the literature that make different assumptions and approximations, yet it is unclear how these affect the accuracy of Pop III star formation history predictions. We present results of a systematic survey of these techniques to establish their strengths and weaknesses. For example, we compare models that utilize dark matter (DM) halo merger trees generated with a Monte Carlo approach based on Extended Press-Schechter formalism to simpler methods that do not take into account full merger history (i.e. trees generated with analytic halo mass function abundance matching, and fully analytic models). We also show for the first time the abundance of stars with newly calculated minimum halo mass where Pop III star formation can occur as a function of a LW feedback and dark matter-baryon streaming.


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