Bulk flows from velocity field surveys: a consistency check


E-mail: dsarkar@uci.edu (DS); feldman@ku.edu (HAF); rwatkins@willamette.edu (RW)


We present an analysis comparing the bulk-flow measurements for six recent peculiar velocity surveys, namely, ENEAR, SFI, RFGC, SBF and the Mark III singles and group catalogues. We study whether the directions of the bulk-flow estimates are consistent with each other and construct the full 3D bulk-flow vectors for each survey. We show that although the surveys differ in their geometry, galaxy morphologies, distance measures and measurement errors, their bulk flow vectors are expected to be highly correlated and in fact show impressive agreement in all cases. We found a combined weighted mean bulk motion of 330 ± 101 km s−1 towards l= 234°± 11° and b= 12°± 9° in a sphere with an effective depth of ∼4000 km s−1.