The Carnegie-Irvine Galaxy Survey. VIII. Demographics of Bulges along
the Hubble Sequence
H. Gao, L. Ho, A. Barth, and Z. Li. (2019)cite arxiv:1901.03195Comment: Submitted to AAS journals; 15 pages (main text), 9 figures, and 2 tables. arXiv admin note: text overlap with arXiv:1806.06350.
We present multi-component decomposition of high-quality $R$-band images of
312 disk galaxies from the Carnegie-Irvine Galaxy Survey. In addition to bulges
and disks, we successfully model nuclei, bars, disk breaks, nuclear/inner
lenses, and inner rings. Our modeling strategy treats nuclear rings and nuclear
bars as part of the bulge component, while other features such as spiral arms,
outer lenses, and outer rings are omitted from the fits because they are not
crucial for accurate bulge measurements. The error budget of bulge parameters
includes the uncertainties from sky level measurements and model assumptions.
Comparison with multi-component decomposition from the Spitzer Survey
of Stellar Structure in Galaxies reveals broad agreement for the majority of
the overlapping galaxies, but for a considerable fraction of galaxies there are
significant differences in bulge parameters caused by different strategies in
model construction. We confirm that on average bulge prominence decreases from
early to late-type disk galaxies, although the large scatter of bulge-to-total
ratios in each morphological bin limits the application of Hubble type as an
accurate predictor of bulge-to-total ratio. In contrast with previous studies
claiming that barred galaxies host weaker bulges, we find that barred and
unbarred spiral galaxies have similar bulge prominence.
The Carnegie-Irvine Galaxy Survey. VIII. Demographics of Bulges along the Hubble Sequence