Exponential bulges and antitruncated disks in lenticular galaxies

TL;DR

This paper investigates the structural features of lenticular galaxies, focusing on exponential bulges and anti-truncated disks, and discusses their formation mechanisms and how to distinguish between different types of stellar structures.

Contribution

It provides a detailed analysis of the structural components in S0 galaxies and proposes methods to differentiate pseudobulges from anti-truncated disks, highlighting formation processes.

Findings

Identification of multi-tier exponential stellar structures in lenticular galaxies

Discussion of mechanisms responsible for anti-truncated disk formation

Examples of axisymmetric S0 galaxies with complex structures

Abstract

The presence of exponential bulges and anti-truncated disks has been noticed in many lenticular galaxies. In fact, it could be expected because the very formation of S0 galaxies includes various processes of secular evolution. We discuss how to distinguish between a pseudobulge and an anti-truncated disk, and also what particular mechanisms may be responsible for the formation of anti-truncated disks. Some bright examples of lenticular galaxies with the multi-tiers exponential stellar structures are presented, among them -- two central group giant S0s seen face-on and perfectly axisymmetric.