RSAA Colloquia / Seminars / Feast-of-Facts: Thursday, 25 January 2018, 14:00-15:00; Duffield Lecture Theatre

Michael Hudson

"The Origin of the Local Group's 600 km/s Motion with respect to the Cosmic Microwave Background"

In standard cosmological perturbation theory, peculiar velocities - or cosmic flows - arise from large-scale structure in the nearby Universe. Since the late 1970s there has been a long-standing effort to map quantitatively the structures in the nearby Universe and to reconcile these with the peculiar velocities of the Local Group and other nearby galaxies. We have now reached the stage where most - but not all - of this motion is understood. I will review recent progress in this area, focusing on our recent work on the 2M++ redshift compilation, which relies heavily on the 6dF and other surveys. I will also discuss how one can obtain constraints on the cosmological parameters from this approach. Finally, I will discuss the prospects from ongoing and future surveys.