Exponential bulges and antitruncated disks in lenticular galaxies

摘要

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