Distances to 18 Dwarf Galaxies from the Arecibo Survey
  Based on the archival Hubble Space Telescope images, we have performed
stellar photometry for 18 dwarf galaxies. Branches of young and old stars are
seen on the constructed Hertzsprung-Russell diagrams. Using the photometry of
red giants and applying the TRGB method, we have determined accurate distances
for all 18 galaxies for the first time. The galaxies AGC238890 and AGC747826
have minimum ($D$ = 5.1 Mpc) and maximum ($D$ = 12.0 Mpc) distances,
respectively. The distances to the remaining galaxies lie within this range.
Low-metallicity galaxies have been identified by measuring the color indices of
the red giant branch: AGC102728, AGC198691, AGC205590, AGC223231, AGC731921,
and AGC747826. We have determined the distance to AGC198691 with a record low
metallicity. Since AGC223254, AGC229053, AGC229379, AGC238890, AGC731921, and
AGC742601 are projected onto the Virgo cluster of galaxies, the distances
estimated by us together with the velocities of these galaxies measured
previously at Arecibo can be used to refine the effect of galaxy infall to the
Virgo cluster.
