IUCAA Colloquium: May 17, 2024

Title: Unveiling the Enigma of Dark Energy through the DESI Galaxy Survey

Speaker: Prof. Shadab Alam (Tata Institute of Fundamental Research (TIFR), Mumbai)

Abstract: The nature of dark energy, the mysterious force driving the accelerated expansion of our universe, remains one of the most profound enigmas in modern cosmology. Despite decades of intense theoretical and observational efforts, the fundamental properties of this elusive component continue to elude our understanding. Unraveling the secrets of dark energy requires a collaborative, multifaceted approach, combining the expertise of scientists and engineers from diverse fields. One of the most promising avenues for probing the nature of dark energy lies in the study of galaxy redshift surveys, which map the large-scale structure of the cosmos with unprecedented precision. The Dark Energy Spectroscopic Instrument (DESI), a cutting-edge experiment currently underway, is at the forefront of this endeavor. In this colloquium, I will delve into the intricacies of the DESI experiment, showcasing its innovative approach to mapping millions of galaxies across vast cosmic distances. By analysing the imprints left by dark energy and neutrino masses on the distribution and motions of these galaxies, DESI aims to shed light on the fundamental constituents of our universe. I will present the latest results from the first year of DESI observations, highlighting the insights gained thus far. Additionally, I will discuss the theoretical developments and analytical frameworks employed to extract the signatures of dark energy and neutrino masses from this rich cosmological dataset. Beyond the realm of dark energy, DESI's unprecedented mapping capabilities hold the potential to uncover new mysteries and challenge our current understanding of the cosmos. This colloquium will explore the broader implications of DESI's findings, offering a tantalising glimpse into the future of cosmological research and the profound questions that lie ahead.