Anirudh Ravishankar

Anirudh Ravishankar   (India)

ravishankar @

Simulating the effects of multiphase gas on the evolution of galaxies

With the advent of highly sensitive telescopes such as JWST and improvements to radio telescopes such as ALMA, it is now possible to observe the gas, dust and stellar content of galaxies across different epochs at sub-/kiloparsec resolution. In contrast, modern cosmological simulations use subgrid approximations to model small-scale physical processes and robustly produce large samples of galaxies and observables. However, these subgrid recipes inhibit a meaningful comparison with observations as their assumptions break down at the small (parsec-)scales where star formation occurs. Specifically, many cosmological simulations today, such as IllustrisTNG, lack the resolution needed to model the different phases of gas on the fly. This predicament has motivated the need to incorporate detailed physics in simulations to accurately model the multiphase gas on global and resolved scales.

To this end, I work on characterizing the nature of star-forming gas in galaxies using the IllustrisTNG simulations and contrast their outcome with those from other current cosmological galaxy programs such as Flamingo and Simba. I primarily use AREPO - a massively parallel MHD code that discretizes the equations of hydrodynamics using an adaptively refined mesh of Voronoi tessellations. Using such codes in the near future, I will go beyond the current state of the art of large-volume simulations by testing a new galaxy formation model that includes the multiphase ISM and more precise implementations of star formation and stellar feedback. At first, I aim to achieve this via zoom-in simulations of individual galaxies with various gas/stellar masses and metallicities. I will then create critical comparisons with recent and upcoming observations of galaxies that are more physically realistic than earlier simulations.

Through my PhD, I plan to build and calibrate hydrodynamical simulations capable of resolving the cold gas in the ISM and help understand the evolution of galaxies with cosmic time.

Supervisor:    Annalisa Pillepich (MPIA)