# The role of previous generations of stars in triggering star formation and driving gas dynamics

**Authors:** Nicholas P. Herrington, Clare L. Dobbs, Thomas J. R. Bending  
**arXiv:** [2304.06659](https://arxiv.org/abs/2304.06659)  
**Date:** 2023-04-13  
**Summary page:** https://www.summarizepaper.com/en/paper/2304.06659v1/

## Key points

- Hydrodynamic and magnetohydrodynamic (MHD) simulations of sub-galactic regions are presented
- The role of prior populations of stars in triggering star formation and driving gas dynamics is investigated
- Including an initial population of stars can improve the initial conditions for region extraction models by triggering new star formation and contributing to gas dynamics
- Early time supernova from the initial population are important in triggering new star formation and driving gas motions on larger scales above 100 pc
- The ionising feedback contribution from the initial population has less impact since many members have cleared out gas around them in prior models
- Simulation results are comparable with using a larger region for the duration of their simulations when a good choice of region is made while extracting smaller regions from large-scale simulations
- MHD has a relatively larger impact than initial conditions, reducing the star formation rate by a factor of 3 at later times
- Magnetic fields should be considered when modelling sub-galactic regions.

## Summary

This paper presents hydrodynamic and magnetohydrodynamic (MHD) simulations of sub-galactic regions, with a focus on the role of prior populations of stars in triggering star formation and driving gas dynamics. The authors investigate the reliability of extracting smaller regions from larger scale simulations, as well as the impact of including an initial population of stars on the simulation results. Simulations of star formation on molecular cloud scales typically start with a turbulent cloud of gas, from which stars form and then undergo feedback. However, in reality, a typical cloud or region within a galaxy may already include or reside near some population of stars containing massive stars undergoing feedback. The authors find that including an initial population can improve the initial conditions for their region extraction models by triggering new star formation and contributing to gas dynamics. The study shows that early time supernova from the initial population are important in triggering new star formation and driving gas motions on larger scales above 100 pc. However, the ionising feedback contribution from the initial population has less impact since many members have cleared out gas around them in prior models. In terms of overall star formation rates though, the initial population has a relatively small effect, and feedback does not suppress subsequent star formation. The authors also examine how sensitive simulation results are to the inclusion of surrounding interstellar medium when extracting smaller regions from large-scale simulations. They find that with a good choice of region, results are comparable with using a larger region for the duration of their simulations. Furthermore, MHD has a relatively larger impact than initial conditions, reducing the star formation rate by a factor of 3 at later times. This highlights the importance of considering magnetic fields when modelling sub-galactic regions. Overall, this study provides insights into how prior populations can affect star formation and gas dynamics in sub-galactic regions while also highlighting considerations for reliable extraction methods and incorporating magnetic fields into simulations.