The Impact of Stellar Initial Mass Function on the Epoch of Reionization: Insights from Semi-Analytic Galaxy Modeling

The adequate choice of stellar initial mass function (IMF) is crucial when studying high-<i>z</i> galaxy formation and the epoch of reionization (EoR) models. We employ the semi-analytical galaxy model <span style="font-variant: small-caps;">L-Galaxies2020</span> an...

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Bibliographic Details
Main Authors: Qingbo Ma, Lei Liu, Peiai Liu
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Universe
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Online Access:https://www.mdpi.com/2218-1997/11/4/129
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Summary:The adequate choice of stellar initial mass function (IMF) is crucial when studying high-<i>z</i> galaxy formation and the epoch of reionization (EoR) models. We employ the semi-analytical galaxy model <span style="font-variant: small-caps;">L-Galaxies2020</span> and the dark matter simulation <span style="font-variant: small-caps;">Millennium-II</span>, in combination with the BPASS spectral model, to investigate the effects of different stellar IMFs on the properties of high-<i>z</i> galaxies and their ionizing photon budget during EoR. We find that different stellar IMFs lead to different SED of high-<i>z</i> galaxies, and thus different ultraviolet luminosity functions (UVLF) and budgets of ionizing photons for EoR. Specifically, at <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>z</mi><mo><</mo><mn>10</mn></mrow></semantics></math></inline-formula>, the UVLF with Salpeter and Chabrier IMF models are closer to the observed results, while at <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>z</mi><mo>></mo><mn>10</mn></mrow></semantics></math></inline-formula>, the ones with a Top-Heavy model are more consistent with the JWST observations. The increase in the upper limit of star mass within stellar IMF from <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>100</mn><mspace width="0.166667em"></mspace><msub><mi mathvariant="normal">M</mi><mo>⊙</mo></msub></mrow></semantics></math></inline-formula> to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>300</mn><mspace width="0.166667em"></mspace><msub><mi mathvariant="normal">M</mi><mo>⊙</mo></msub></mrow></semantics></math></inline-formula> results in the increase in the UVLF and the ionizing photon number density.
ISSN:2218-1997