Optical surface brightness fluctuations of shell galaxies toward 100 Mpc

We measure F814W surface brightness fluctuations ( SBFs) for a sample of distant shell galaxies with radial velocities ranging from 4000 to 8000 km s(-1). The distance at galaxies is then evaluated by using the SBF method. For this purpose, theoretical SBF magnitudes for the HSTACS filters are computed for single- burst stellar populations covering a wide range of ages ( t= 1.5-14 Gyr) and metallicities ( Z = 0: 008-0.04). Using these stellar population models, we provide the first (M) over bar (F814W) versus ( F475W - F814W)(0) calibration and we extend the previous M-1 versus ( B - I)(0) color relation to colors ( B - I)(0) <= 2.0mag. Coupling our SBF measurements with the theoretical calibration we derive distances with a statistical uncertainty of similar to 8%, and systematic error of similar to 6%. The procedure developed to analyze data ensures that the indetermination due to possible unmasked residual shells is well below similar to 12%. The results suggest that optical SBFs can be measured at d >= 100 Mpc with HSTACS imaging. SBF- based distances coupled with recession velocities corrected for peculiar motion, allow us obtain H-0= 76 +/- 6 ( statistical) +/- 5 ( systematic) km s(-1) Mpc(-1).