# Effect of the environment on star formation activity and stellar mass for star-forming galaxies in the COSMOS field

**Authors:** S. M. Randriamampandry, M. Vaccari, K. M. Hess  
**arXiv:** [2008.13131](https://arxiv.org/abs/2008.13131)  
**Date:** 2020-08-30  
**Summary page:** https://www.summarizepaper.com/en/paper/2008.13131v1/

## Key points

- Randriamampandry et al. investigate the relationship between the environment and the galaxy main sequence as well as radio luminosity
- They use the VLA-COSMOS 3 GHz catalogue, including star-forming galaxies and quiescent galaxies, in three distinct environments and for three different galaxy types
- The authors conduct a comparative analysis of the distribution of star-forming galaxies with respect to the main sequence consensus region
- The study supports previous research indicating that star formation rate decreases over cosmic time
- The slope of the main sequence for various redshift and stellar mass bins is shallower than the consensus main sequence, evolving towards higher redshift bins regardless of environmental factors
- No significant trends in star formation rate are observed concerning both environments and galaxy types due to large errors
- Environmental conditions do not cause flattening of the main sequence at high stellar masses, suggesting other mechanisms may be responsible
- The study provides valuable insights into how environmental factors influence star formation activity and stellar mass in galaxies by considering different environments and galaxy types, as well as incorporating radio observations

## Summary

In their study, Randriamampandry et al. investigate the relationship between the environment and the galaxy main sequence (the correlation between stellar mass and star formation rate) as well as the relationship between the environment and radio luminosity to gain new insights into how environments affect galaxies. They utilize the VLA-COSMOS 3 GHz catalogue, which includes star-forming galaxies (SFGs) and quiescent galaxies (AGN), in three distinct environments (field, filament, cluster) and for three different galaxy types (satellite, central, isolated). The authors conduct a comparative analysis of the distribution of SFGs with respect to the main sequence consensus region from previous literature. They consider galaxy environment and employ radio observations within a redshift range of 0.1 ≤ z ≤ 1.2. The findings of this study support previous research indicating that star formation rate (SFR) decreases over cosmic time. Interestingly, they discover that the slope of the main sequence for various redshift and stellar mass bins is shallower than the consensus main sequence, gradually evolving towards higher redshift bins regardless of environmental factors. However, due to large errors no significant trends in SFR are observed concerning both environments and galaxy types. Furthermore, their sample does not indicate that environmental conditions cause flattening of the main sequence at high stellar masses; suggesting that other mechanisms may be responsible for this phenomenon. Overall, this study provides valuable insights into how environmental factors influence star formation activity and stellar mass in galaxies by considering different environments and galaxy types as well as incorporating radio observations; contributing to our understanding of how galaxies evolve within their surroundings.