A Strong Dichotomy in S0 Disk Profiles Between the Virgo Cluster and the Field

TL;DR

This study reveals a significant environmental difference in S0 galaxy disk profiles, with Virgo Cluster S0s lacking truncations and showing more Type I profiles compared to field S0s, indicating different formation processes.

Contribution

It provides the first clear evidence of a strong dichotomy in S0 disk profiles between cluster and field environments, highlighting environmental influence on galaxy structure.

Findings

Virgo S0s lack disk truncations entirely.

Field S0s have a mix of profile types, including truncations.

Type I profiles are more common in Virgo S0s.

Abstract

We report evidence for a striking difference between S0 galaxies in the local field and in the Virgo Cluster. While field S0 galaxies have disks whose surface-brightness profiles are roughly equally divided between the three main types (Types I, II, and III: single-exponential, truncated, and antitruncated), Virgo S0s appear to be entirely lacking in disk truncations. More specifically, the fraction of truncations in S0 galaxies with M_B < -17 is 28% +7/-6% for the field, versus 0% +4/-0% for the Virgo Cluster galaxies; the difference is significant at the 99.7% level. The discrepancy is made up almost entirely by Type I profiles, which are almost twice as frequent in the Virgo Cluster as they are in the field. This suggests that S0 formation may be driven by different processes in cluster and field environments, and that outer-disk effects can be useful tests of S0 formation models.