Do Bulges of Early- and Late-type Spirals Have Different Morphology?
Abstract
We study HST/NICMOS H-band images of bulges of two equal-sized samples of early- (T(RC3) < 4) and late-type spiral (mainly Sbc-Sc) galaxies matched in outer disk axis ratio. We find that bulges of late-type spirals are more elongated than their counterparts in early-type spirals. Using a KS-test we find that the two distributions are different at the 98.4% confidence level. We conclude that the two data sets are different, i.e. late-type galaxies have a broader ellipticity distribution and contain more elongated features in the inner regions. We discuss the possibility that these would correspond to bars at a later evolutionary stage, i.e. secularly evolved bars. Consequent implications are raised, and we discuss relevant questions regarding the formation and structure of bulges. Are bulges of early-type and late-type spirals different? Are their formation scenarios different? Can we talk about bulges in the same way for different types of galaxies?
Cite
@article{arxiv.astro-ph/0305326,
title = {Do Bulges of Early- and Late-type Spirals Have Different Morphology?},
author = {K. Fathi and R. F. Peletier},
journal= {arXiv preprint arXiv:astro-ph/0305326},
year = {2009}
}
Comments
Submitted to A & A (accepted); Please find high resolution version on http://www.astro.uu.se/~kambiz/DOC/paper-bulges.pdf