# Star formation in low-redshift cluster dwarf galaxies

## TL;DR

This study analyzes how dwarf galaxies in low-redshift clusters are affected by their environment, revealing increased star formation activity and morphological changes in the outskirts, with evidence of quenching near the cluster centers.

## Contribution

It provides new insights into the environmental effects on dwarf galaxy luminosity functions, blue fractions, and morphology within galaxy clusters, using extensive archival data.

## Key findings

- DGR increases towards cluster outskirts, especially in u-band.
- Dwarf galaxies have a higher blue fraction than giants across all distances.
- Inner cluster regions show more nucleated dwarf galaxies, indicating environmental influence.

## Abstract

Evolution of galaxies in dense environments can be affected by close encounters with neighbouring galaxies and interactions with the intracluster medium. Dwarf galaxies (dGs) are important as their low mass makes them more susceptible to these effects than giant systems. Combined luminosity functions (LFs) in the r- and u-band of 15 galaxy clusters were constructed using archival data from the Canada-France-Hawaii Telescope. LFs were measured as a function of cluster-centric radius from stacked cluster data. Marginal evidence was found for an increase in the faint-end slope of the u-band LF relative to the r-band with increasing cluster-centric radius. The dwarf-to-giant ratio (DGR) was found to increase toward the cluster outskirts, with the u-band DGR increasing faster with cluster-centric radius compared to the r-band. The dG blue fraction was found to be ~2 times larger than the giant galaxy blue fraction over all cluster-centric distance (~5sigma level). The central concentration (C) was used as a proxy to distinguish nucleated versus non-nucleated dGs. The ratio of high-C to low-C dGs was found to be ~2 times greater in the inner cluster region compared to the outskirts (2.8sigma level). The faint-end slope of the r-band LF for the cluster outskirts (0.6 < r/r_200 < 1.0) is steeper than the SDSS field LF, while the u-band LF is marginally steeper at the 2.5sigma level. Decrease in the faint-end slope of the r- and u-band cluster LFs towards the cluster centre is consistent with quenching of star formation via ram pressure stripping and galaxy-galaxy interactions.