Accurate Distances to Important Spiral Galaxies: M63, M74, NGC 1291, NGC
  4559, NGC 4625, NGC 5398
  Accurate distances are fundamental to interpreting many measured properties
of galaxies. Surprisingly, many of the best-studied spiral galaxies in the
Local Volume have distance uncertainties that are much larger than can be
achieved with modern observations. Using Hubble Space Telescope optical
imaging, we use the tip of the red giant branch method to measure the distances
to six galaxies that are included in the Spitzer Infrared Nearby Galaxies
Survey (SINGS) program and its offspring surveys. The sample includes M63, M74,
NGC 1291, NGC 4559, NGC 4625, and NGC 5398. We compare our results with
distances reported to these galaxies based on a variety of methods. Depending
on the technique, there can be a wide range in published distances,
particularly from the Tully-Fisher relation. In addition, differences between
the Planetary Nebula Luminosity Function and Surface Brightness Fluctuation
techniques can vary between galaxies suggesting inaccuracies that cannot be
explained by systematics in the calibrations. Our distances improve upon
previous results as we use a well-calibrated, stable distance indicator,
precision photometry in an optimally selected field of view, and a Bayesian
Maximum Likelihood technique that reduces measurement uncertainties.
