WHY ARE CLASSICAL BULGES MORE COMMON IN LENTISOCIAL GALAXIES THAN IN SPIRAL GALAXIES?
In this paper, we try to understand why the classical bulge fraction observed in SO and Sc galaxies is significantly higher than in Sa galaxies. We conduct a comparative study of the bulge and global properties of a sample of spiral and lenticular galaxies in a fixed environment. Our sample consists of 1101 (Sa,Sb,Sc, SBa,SBb,SBc) spiral galaxies. We classified the bulges into five categories based on their positions in the Kormendy diagram and others. In addition, this paper discusses the reasons why classical bulges are more common in lenticular galaxies than in spiral galaxies. The main processes of formation of these structures, their evolutionary features and influences exerted by different types of interactions and mergers of galaxies are analyzed. Based on observational data and theoretical models, differences in the mechanisms of formation and evolution of bulges in lenticular and spiral systems are studied.
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