Event calendar file
State of the Universe
Challenges and Opportunities at non-linear scales of Large Scale Structure
by Dr. Shadab Alam (Royal Observatory, Edinburgh, UK)
Wednesday, February 16, 2022
from
to
(Asia/Kolkata)
at Zoom link: https://zoom.us/j/94153492290?pwd=enlGMC9MaUlkMjRnN1V4NGE0QjFHUT09 Meeting ID: 941 5349 2290 Passcode: 645003
at Zoom link: https://zoom.us/j/94153492290?pwd=enlGMC9MaUlkMjRnN1V4NGE0QjFHUT09 Meeting ID: 941 5349 2290 Passcode: 645003
| Description |
The initial metric perturbations in the universe were small O(10-5) allowing linearised equations to give a very good description of the evolution of the Universe. The standard model predicts the evolution of the clustering statistics (e.g. P(k)) of the matter distribution. Under the simplified assumption, all the complex physics of galaxy formation is encompassed in a few parameters called the galaxy biases. We know that these assumptions fail as we approach scales equivalent to the size of a galaxy. While such solutions were appropriate for the past experiments, (e.g: SDSS), they fall short for the measurement precision of ongoing experiments (e.g: DESI, EUCLID, LSST) which are better by more than an order of magnitude. Therefore, one of the challenges is to understand the limits of the current models to a precision better than ongoing experiments to avoid biases in interpreting the underlying physics of the universe. This is challenging because of two reasons: first, the growth of density perturbations and its coupling to the velocity field becomes highly non-linear, and second, high precision true predictions require understanding the physics of galaxy formation. At the same time, there is a golden opportunity to improve upon the models by identifying the dominant failure modes. I will describe our efforts to validate and improve the theoretical models especially focusing on the redshift space two-point clustering statistics and its implications on our ability to derive physics from ongoing experiments. |
| Material: |
