HI selected galaxies in the Sloan Digital Sky Survey
West, Andrew Alan, 1977-
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We present the results from a study of HI selected galaxies that fall within both the HI Parkes All Sky Survey (HIPASS) and the Sloan Digital Sky Survey (SDSS). By comparing the optical properties derived from the SDSS five-band photometry with the HI properties from HIPASS, we are able to probe the relationship between the stellar population and the neutral gas over a range of Hubble types. Our HIPASS/SDSS catalog provides a uniform data set that is used to investigate the physical factors that contribute to star formation on global scales in galaxies. The HI selection has allowed us to identify a significant group of low surface brightness galaxies not included in most SDSS studies. We also find that the colors of the HI selected galaxies are offset from those of a volume-limited sample of SDSS galaxies. This can be explained by a recent burst of star formation in the HI selected galaxies and may point to a recent acquisition of cold gas. We synthesize model galaxy colors using the Bruzual & Charlot (2003) population synthesis grids and use these colors to derive rough star formation histories and metallicities for the HIPASS/SDSS sample galaxies. Many of the HIPASS/SDSS galaxies have colors that do not fall on the Bruzual & Charlot model grids. However, most of the discrepant sources can be explained as galaxies whose colors are dominated by emission lines rather than the underlying stellar populations. We also utilize the dynamical information derived from the HI line widths and investigate the Tully-Fisher relation in HI selected galaxies. The combination of HI and optical data allow us to examine the "baryonic" Tully-Fisher (BTF) relation. We find that the scatter in the (BTF) correlates with the baryonic mass fraction and is predicted by fundamental disk galaxy formation scenarios. In addition, the construction of this catalog has let to a set of tools to aid in the analysis of large nearby galaxies in the SDSS.
- Astronomy