  We measured high-quality surface brightness fluctuation (SBF) distances for a
sample of 63 massive early-type galaxies using the WFC3/IR camera on the Hubble
Space Telescope. The median uncertainty on the SBF distance measurements is
0.085 mag, or 3.9% in distance. Achieving this precision at distances of 50 to
100 Mpc required significant improvements to the SBF calibration and data
analysis procedures for WFC3/IR data. Forty-two of the galaxies are from the
MASSIVE Galaxy Survey, a complete sample of massive galaxies within ~100 Mpc;
the SBF distances for these will be used to improve the estimates of the
stellar and central supermassive black hole masses in these galaxies.
Twenty-four of the galaxies are Type Ia supernova hosts, useful for calibrating
SN Ia distances for early-type galaxies and exploring possible systematic
trends in the peak luminosities. Our results demonstrate that the SBF method is
a powerful and versatile technique for measuring distances to galaxies with
evolved stellar populations out to 100 Mpc and constraining the local value of
the Hubble constant.
