SURFACE BRIGHTNESS FLUCTUATION DISTANCES TO NGC-4494 AND NGC-4565 ANDTHE VIRGOCENTRIC INFALL

The distances to NGC 4565 and NGC 4494 have been measured using the su rface brightness fluctuation method in the V band. By adopting a fluct uation magnitude M(V)=+1.0, we have determined a distance modulus of 3 0.88(-0.26)(+0.31) (d= 15.0(-1.7)(+2.3) Mpc) for NGC 4494, and a dista nce of 30.08 +/- 0.07 (10.4(-0.3)(+0.4) Mpc) for NGC 4565. Both NGC 44 94 and the bulge of NGC 4565 possess very similar colors, so that it i s unlikely that differences in stellar population strongly affect thes e distance measurements. Previous studies of these two galaxies had su ggested that they are both members of the Coma I group. Our measuremen ts are incompatible with this hypothesis, but are in good agreement wi th Virgocentric infall models, which demonstrate that the difference i n distances for NGC 4494 and NGC 4565 is probably due to the ''triple- value ambiguity'' in the Virgocentric infall pattern.