HI Deficiencies and Asymmetries in HIPASS Galaxies
  We present an analysis of the sky distribution of neutral hydrogen (HI)
deficiency and spectral asymmetry for galaxies detected by the HI Parkes
All-Sky Survey (HIPASS) as a function of projected environment density.
Previous studies of galaxy HI deficiency using HIPASS were sensitive to
galaxies that are extremely HI rich or poor. We use an updated binning
statistic for measuring the global sky distribution of HI deficiency that is
sensitive to the average deficiencies. Our analysis confirms the result from
previous studies that galaxies residing in denser environments, such as Virgo,
are on average more HI deficient than galaxies at lower densities. However,
many other individual groups and clusters are not found to be on average
significantly HI poor, in contradiction to previous work. In terms of HI
spectral asymmetries, we do not recover any significant trend of increasing
asymmetry with environment density as found for other galaxy samples. We also
investigate the correlation between HI asymmetry and deficiency, but find no
variation in the mean asymmetry of galaxies that are HI rich, normal or poor.
This indicates that there is either no dependence of asymmetry on HI
deficiency, or a galaxy's HI deficiency only has a small influence on the
measured HI asymmetry that we are unable to observe using only integrated
spectra.
