  We present a self consistent nonparametric model of the local cosmic velocity
field based on the density distribution in the PSCz redshift survey of IRAS
galaxies. The error analysis, carried out on mock PSCz catalogues constructed
from N-body simulations, reveals uncertainties of ~70 km/sec. The denser
sampling provided by the PSCz survey compared to previous IRAS galaxy surveys
allows us to reconstruct the velocity field out to larger distances. The most
striking feature of the model velocity field is a coherent large-scale
streaming motion along a baseline connecting Perseus-Pisces, the Local
Supercluster, the Great Attractor, and the Shapley Concentration. We find no
evidence for back-infall onto the Great Attractor. Instead, material behind and
around the Great Attractor in inferred to be streaming towards the Shapley
Concentration The PSCz model velocities compare well with those predicted from
the 1.2Jy redshift survey of IRAS galaxies and with those predicted from the
distribution of Abell/ACO clusters, out to 140 Mpc/h. Comparison of the
real-space density fields (or, alternatively, the peculiar velocity fields)
inferred from the PSC$z$ and cluster catalogues gives a relative (linear) bias
parameter between clusters and IRAS galaxies of 4.4 +/- 0.6. Finally, we
compare the cumulative bulk flows predicted from the PSCz gravity field with
those measured from the Mark III and SFI catalogues of peculiar velocities. A
conservative estimate of beta=Omega**0.6/b, where b is the bias parameter for
IRAS galaxies, gives beta =0.6 + 0.22 -0.15, in agreement with other recent
determinations.
