Data: 15.12.2022

Palestrante: Dr. Cullan Howlett (University of Queensland)

Link: https://youtu.be/62PLTWxewQY

Resumo: Direct measurements of galaxy peculiar velocities, i.e., their motions with respect to us beyond that expected from just the expansion of the Universe, are undergoing a resurgence. Five years ago, individual surveys were limited to a few thousand galaxies and to within the z~0.05 Universe. With the newest state-of-the-art, the number of galaxies, and the cosmological volume they cover, will increase by more than an order of magnitude. In this talk I will present the motivation and mechanisms for carrying out these measurements, focusing on both how they can be used to provide more precise tests of General Relativity on large scales than are possible with just galaxy redshifts, and how they can be used to create detailed cosmographic maps of hidden structures in the nearby Universe. As an example, I will discuss the construction and new cosmological results from my recently released Sloan Digital Sky Survey peculiar velocity catalogue. I will finish the talk by highlighting the exciting upcoming results we expect from the next generation of peculiar velocity surveys being carried out with the Dark Energy Spectroscopic Instrument (DESI) and 4-Metre Multi-Object Spectroscopic Telescope (4MOST).