# Variations of the stellar Initial Mass Function in Semi-Analytic Models: implications for the mass assembly of galaxies in the GAEA model

## TL;DR

This paper uses the GAEA semi-analytic model to explore how variations in the stellar initial mass function affect galaxy mass estimates and evolution, providing insights into observed discrepancies and cosmic history.

## Contribution

It introduces a model with variable IMF prescriptions that impact galaxy mass and star formation history predictions, improving understanding of galaxy evolution.

## Key findings

- Variable IMF leads to higher stellar mass estimates.
- Explains the mismatch between photometric and dynamical masses.
- Impacts the inferred evolution of galaxy stellar mass functions.

## Abstract

A wealth of observations recently challenged the notion of a universal stellar initial mass function (IMF) by showing evidences in favour of a variability of this statistical indicator as a function of galaxy properties. I present predictions from the semi-analytic model GAEA (GAlaxy Evolution and Assembly), which features (a) a detailed treatment of chemical enrichment, (b) an improved stellar feedback scheme, and (c) implements theoretical prescriptions for IMF variations. Our variable IMF realizations predict intrinsic stellar masses and mass-to-light ratios larger than those estimated from synthetic photometry assuming a universal IMF. This provides a self-consistent interpretation for the observed mismatch between photometrically inferred stellar masses of local early-type galaxies and those derived by dynamical and spectroscopic studies. At higher redshifts, the assumption of a variable IMF has a deep impact on our ability to reconstruct the evolution of the galaxy stellar mass function and the star formation history of galaxies.