There are several main points which the SBF survey has to make about peculiar velocities in the universe and large scale flows. First, we find the distance of the Virgo core to be about 15.8 Mpc, and the Hubble constant to be about 85 km/s/Mpc. At the present we prefer the tie to large scale afforded by TF and Dn-sigma to the purely SBF tie from fitting Virgo infall. As more distant galaxies are measured with SBF we will gain more confidence that we have indeed linked to the global Hubble flow with SBF. I must stress that these exact numbers are subject to change at the 10 percent level as we finalize our photometry and new Cepheid distances come in. By late this year we should have a very solid tie to the Cepheid scale, spanning 0.75 Mpc to 20 Mpc, and including clusters of major importance such as Fornax, Virgo, Leo, and the N1023 group. However, at present we are tied to Cepheids, and if the Cepheid scale changes, our scale will change.
One final point which I'd like to make is that it worries me that these mysterious flows, evidenced by the quadrupole here, or at larger scales as bulk flows appearing from TF or Dn-sigma distances, have two properties: (a) there is no good evidence for backside infall except in the Virgo supercluster, and (b) they lie in the galactic plane. I know that there are lots of galaxies hiding in the plane in the Hydra-Centaurus region, and that Perseus-Pisces happens to lie near the plane. But still I worry about funny, gray extinction, and I wince every time I hear people talk about "reddening correction" as opposed to the more accurate "extinction correction". I would recommend to everyone that galactic extinction be examined very closely every time a large scale flow is seen, and that we not take for granted that extinction can be uniformly determined from HI column density or reddening. It doesn't take much to make a huge bulk flow.
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