The Consistency of Cosmic Flows on 100 Mpc/h Scales

Abstract

We have compared the bulk flow of recent large-scale peculiar velocity surveys (SMAC, SC, Lauer and Postman, Willick, EFAR and Tonry's SNIa sample) to each other, allowing for the errors due to sparse sampling. We conclude that, contrary to the current perception, there is no significant conflict between these surveys. The combined peculiar velocity dataset samples a volume $\sim 100 \h^{-1}$ mpc in radius and has a bulk flow of $350 \pm 80 $ km/s. Allowing for the sparse sampling, we find that this result is not in conflict with the $Λ$CDM models. Structure(s) responsible for the large-scale motion have not yet been identified, but some likely suspects are presently under surveillance.