Astrophysics Webinar

In the Lambda cold dark matter paradigm of hierarchical structure formation, galaxies grow via mergers and by accreting of cold gas along cosmic filaments. On the other hand, non-axisymmetric structures such as spiral arms, bars shape-up the long-term evolution in disc galaxies. Understanding mass assembly, secular evolution, and excavating morpho-kinematic signatures imprinted by merger events holds the key to unravel the detailed evolutionary pathways of galaxies. The Milky Way (which harbours both spiral arms and a stellar bar), plays a pivotal role in decoding the evolutionary pathway of disc galaxies. Empowered with the European Space Agency's Gaia mission, the Milky Way offers a unique opportunity to carry out detailed photometric, spectroscopic, and dynamical studies on an individual star-by-star basis, in a way that is impossible for external galaxies. In this talk, I will discuss some of the kinetic structures in the phase-space distribution of stars in the Solar vicinity and beyond (as unveiled by Gaia), and how understanding their origin can potentially lead to a better understanding of the Milky Way’s evolution over cosmic time. I will further explore how the recent observations of high-redshift galaxies (z ~ 1.1-3), as unveiled by JWST, can be instrumental in gaining an overall understanding of evolution of disc galaxies in the last 8-10 billion years.