# Chemical evolution of elliptical galaxies with a variable IMF -- A publicly available code

## TL;DR

This paper introduces an open-source galaxy evolution simulation code that dynamically adjusts the initial mass function based on the galaxy's star formation rate and metallicity, improving the modeling of chemical evolution in elliptical galaxies.

## Contribution

It presents the first publicly available simulation code implementing a variable IMF according to the IGIMF theory, coupling it with galaxy evolution models.

## Key findings

- Variable IMF affects metallicity and alpha-enhancement evolution.
- The code demonstrates differences from invariant IMF models.
- Time-dependent IMF leads to more realistic chemical abundance predictions.

## Abstract

Growing evidence in recent years suggests a systematic variation of the stellar initial mass function (IMF), being top-heavy for starburst galaxies and possibly bottom-heavy for massive ellipticals. Galaxy chemical evolution simulations adopting an invariant canonical IMF face difficulty in simultaneously reproducing the metallicity and $\alpha$-enhancement of the massive elliptical galaxies. Applying a variable IMF that changes with time is a promising solution, however, it is non-trivial to couple a variable IMF theory with the existing galaxy evolution codes. Here we present the first open source simulation code which recalculates the galaxy-wide IMF at each time step according to the Integrated-Galactic-IMF (IGIMF) theory where the galaxy-wide IMF depends on the galactic star formation rate and metallicity. The resulting galaxy-wide IMF and metal abundance evolve with time. With this pilot work, we explore the effect of the IGIMF theory on galaxy chemical evolution in comparison with an invariant IMF.