Speaker: Clemens Jakubec (Imperial College London)

Title: Looking for anomalies in CMB gravitational lensing

Abstract: The Cosmic Microwave Background (CMB) provides one of the most exciting avenues for modern cosmology to study the past, present and the eventual fate of our universe. As a consequence, in the last decades a great deal of attention has been given to the study of CMB anisotropies, minute fluctuation in the background radiation. One of the most striking features of the CMB is the so-called Cold Spot, an extended cold region in the southern hemisphere. Numerous studies have been devoted to exploring its properties and potential causes. Since maps of the CMB lensing, the way the CMB light is bent by matter in the universe, are now available it is only natural to ask if anomalies analogous to the Cold Spot exist in the lensing data.

In this talk I will quickly introduce the necessary basics of CMB physics and CMB lensing. I will then provide some insight into the Cold Spot, how it was discovered and why physicists think it is (or isn’t) important. I will then move on to the search for extremal spots in the lensing data. Finally, I shall conclude with the results of our study and what they can tell us about the universe.