# The star formation histories of dwarf galaxies in Local Group cosmological simulations

## TL;DR

This study uses cosmological simulations to analyze star formation histories of dwarf galaxies, revealing mass and environment-dependent trends consistent with observations, and highlights the need for deeper data to confirm these predictions.

## Contribution

The paper demonstrates that cosmological simulations can reproduce observed star formation trends in dwarf galaxies, emphasizing the roles of galaxy mass and environment.

## Key findings

- Faint field dwarfs have declining SFHs.
- Brighter dwarfs show increasing SFHs.
- Satellite dwarfs have suppressed recent star formation.

## Abstract

We use the APOSTLE and Auriga cosmological simulations to study the star formation histories (SFHs) of field and satellite dwarf galaxies. Despite sizeable galaxy-to-galaxy scatter, the SFHs of APOSTLE and Auriga dwarfs exhibit robust average trends with galaxy stellar mass: faint field dwarfs ($10^5<M_{\rm star}/M_\odot<10^{6.5}$) have, on average, steadily declining SFHs, whereas brighter dwarfs ($10^{7.5}<M_{\rm star}/M_\odot<10^{9}$) show the opposite trend. Intermediate-mass dwarfs have roughly constant SFHs. Satellites exhibit similar average trends, but with substantially suppressed star formation in the most recent $\sim 5$ Gyr, likely as a result of gas loss due to tidal and ram-pressure stripping after entering the haloes of their primaries. These simple mass and environmental trends are in good agreement with the derived SFHs of Local Group (LG) dwarfs whose photometry reaches the oldest main sequence turnoff. SFHs of galaxies with less deep data show deviations from these trends, but this may be explained, at least in part, by the large galaxy-to-galaxy scatter, the limited sample size, and the large uncertainties of the inferred SFHs. Confirming the predicted mass and environmental trends will require deeper photometric data than currently available, especially for isolated dwarfs.