The Velocity Field of the Local Universe from Measurements of Type Ia Supernovae

We present a measurement of the velocity flow of the local universe relativeto the CMB rest frame, based on the Jha, Riess & Kirshner (2007) sample of 133low redshift type Ia supernovae. At a depth of 4500 km/s we find a dipoleamplitude of 279+-68 km/s in the direction (l,b) = (285+-18,-10+-15),consistent with earlier measurements and with the assumption that the localvelocity field is dominated by the Great Attractor region. At a larger depth of5900 km/s we find a shift in the dipole direction towards the Shapleyconcentration. We also present the first measurement of the quadrupole term inthe local velocity flow at these depths. Finally, we have performed detailedstudies based on N-body simulations of the expected precision with which thelowest multipoles in the velocity field can be measured out to redshifts oforder 0.1. Our mock catalogues are in good agreement with current observations,and demonstrate that our results are robust with respect to assumptions aboutthe influence of local environment on the type Ia supernova rate.