# Evidence of pre-processing and a dependence on dynamical state for low-mass satellite galaxies

## TL;DR

This study investigates how the star formation and morphology of low-mass satellite galaxies depend on group dynamics and pre-processing effects, revealing that dynamical state influences star formation rates but not morphology at small radii.

## Contribution

It provides new insights into the role of group dynamical state and pre-processing in shaping satellite galaxy properties, especially highlighting differences between Gaussian and non-Gaussian groups.

## Key findings

- Star formation rates at small radii depend on group dynamical state.
- Pre-processing effects increase with halo mass, especially for low-mass galaxies.
- Galaxies in non-Gaussian groups show higher star-forming fractions at small radii.

## Abstract

We study the dependence of satellite star formation rate and morphology on group dynamics for a sample of SDSS groups. We classify the group dynamical state and study satellite properties for populations of galaxies at small and large group-centric radii. For galaxies at large radii we find no differences in the star-forming or disc fraction for those in Gaussian groups compared to those in non-Gaussian groups. By comparing the star-forming and disc fractions of infalling galaxies to field galaxies we find evidence for the pre-processing of both star formation rate and morphology. The strength of pre-processing increases with halo mass and is highest for low-mass galaxies infalling onto high-mass haloes. We show that the star formation rate of galaxies at small radii correlates with group dynamical state, with galaxies in non- Gaussian groups showing enhanced star-forming fractions compared to galaxies in Gaussian groups. Similar correlations are not seen for the disc fractions of galaxies at small radii. This seems to suggest that either the mechanisms driving star formation quenching at small halo-centric radii are more efficient in dynamically relaxed groups, or that non-Gaussian groups have assembled more recently and therefore satellites of the groups will have been exposed to these transforming mechanisms for less time.