# Disruption of satellite galaxies in simulated groups and clusters: the roles of accretion time, baryons, and pre-processing

**Authors:** Yannick M. Bahé, Joop Schaye, David J. Barnes, Claudio Dalla Vecchia, Scott T. Kay, Richard G. Bower, Henk Hoekstra, Sean L. McGee, Tom Theuns  
**arXiv:** [1901.03336](https://arxiv.org/abs/1901.03336)  
**Date:** 2019-01-10  
**Summary page:** https://www.summarizepaper.com/en/paper/1901.03336v2/

## Key points

- Study investigates disruption of satellite galaxies in groups and clusters with total mass above 10^10 M_sun
- Utilizes Hydrangea simulations, consisting of 24 high-resolution cosmological hydrodynamical zoom-in simulations based on EAGLE model
- Approximately 50% of satellite galaxies survive until redshift z = 0
- Higher survival fractions observed in massive clusters compared to groups, with minor differences between baryonic and pure N-body simulations
- Majority (up to 90%) of galaxy disruption occurs within lower-mass sub-groups during pre-processing
- Satellites in massive clusters accreted at z < 2 and not undergone pre-processing have a survival rate of 96%
- Only a small percentage of disrupted satellites merge with other satellites even in low-mass groups
- Survival fraction changes rapidly from less than 10% for those accreted at high z to over 90% at low z, more pronounced for more massive galaxies and those accreted onto less massive haloes
- Weak correlations found between satellite disruption and pre-accretion baryon content, star formation rate, and size
- Satellite disruption primarily driven by gravitational processes rather than baryonic effects

## Summary

In this study, the authors investigate the disruption of satellite galaxies in groups and clusters with a total mass (including dark matter and baryons) above 10^10 M_sun. They utilize the Hydrangea simulations, which consist of 24 high-resolution cosmological hydrodynamical zoom-in simulations based on the EAGLE model. The simulations reveal that approximately 50% of satellite galaxies survive until redshift z = 0. Moreover, higher survival fractions are observed in massive clusters compared to groups, with only minor differences between baryonic and pure N-body simulations. Interestingly, the majority (up to 90%) of galaxy disruption occurs within lower-mass sub-groups during pre-processing. For satellites in massive clusters that were accreted at z < 2 and have not undergone pre-processing, an impressive 96% survive. Additionally, it is found that only a small percentage of disrupted satellites merge with other satellites even in low-mass groups. The survival fraction exhibits a rapid change from less than 10% for those accreted at high z to over 90% at low z; this shift is more pronounced for more massive galaxies and those accreted onto less massive haloes. Surprisingly, the disruption of satellite galaxies shows only weak correlations with their pre-accretion baryon content, star formation rate and size; consequently surviving galaxies appear to be nearly unbiased in these properties. These findings suggest that satellite disruption in massive haloes is relatively uncommon and primarily driven by gravitational processes rather than baryonic effects. Overall, this study provides valuable insights into the dynamics and fate of satellite galaxies within group and cluster environments.