The structure of large-scale stellar disks in cluster lenticular galaxies

TL;DR

This study analyzes the structure of stellar disks in 60 lenticular galaxies within clusters, classifying their surface-brightness profiles and exploring environmental effects on disk morphology and evolution.

Contribution

It provides a detailed structural analysis of large-scale stellar disks in cluster lenticular galaxies, including disk thickness and profile classification, highlighting environmental influences.

Findings

Type-II profiles are nearly absent in clusters but common in the field.

Type-III profiles are similarly distributed in clusters and the field.

Cluster environments may promote stellar migration affecting disk structure.

Abstract

By obtaining imaging data in two photometric bands for 60 lenticular galaxies - members of 8 southern clusters - with the Las Cumbres Observatory one-meter telescope network, we have analyzed the structure of their large-scale stellar disks. The parameters of radial surface-brightness profiles have been determined (including also disk thickness), and all the galaxies have been classified into pure exponential (Type I) disk surface-brightness profiles, truncated (Type II) and antitruncated (Type III) piecewise exponential disk surface-brightness profiles. We confirm the previous results of some other authors that the proportion of surface-brightness profile types is very different in environments of different density: in the clusters the Type-II profiles are almost absent while according to the literature data, in the field they constitute about one quarter of all lenticular galaxies. The Type-III profiles are equally presented in the clusters and in the field, while following similar scaling relations; but by undertaking an additional structural analysis including the disk thickness determination we note that some Type-III disks may be a combination of a rather thick exponential pseudobulge and an outer Type-I disk. Marginally we detect a shift of the scaling relation toward higher central surface brightnesses for the outer segments of Type-III disks and smaller thickness of the Type-I disks in the clusters. Both effects may be explained by enhanced radial stellar migration during disk galaxy infall into a cluster that in particular represents an additional channel for Type-I disk shaping in dense environments.