Research

         PhD projects

Emission line galaxies at high redshifts:

My current PhD project highlights one of the most intriguing phases in the evolution of the universe—galaxies residing in the Epoch of Reionization era (z ∼ 7–9). My research primarily focuses on understanding the physical conditions and evolution of emission line galaxies at these high redshifts. Utilizing a combination of analytic galaxy formation models and advanced photoionization modelling with the MAPPINGS V v5.2.1 code, I explore key factors influencing emission line properties, such as metallicity, pressure, ionization parameter, and turbulence within the interstellar medium (ISM).

The primary ideas in my research include:

• Emission Line Diagnostics: Examining the [O III]/Hβ flux ratios and their dependencies on galaxy properties like metallicity, ionization parameters etc. This research aids in interpreting observations from advanced telescopes such as JWST, enhancing our understanding of early galaxies' physical conditions.

• Turbulence in High-Redshift Galaxies: Investigating how turbulence impacts ISM density and observable properties such as emission line ratios.

• AGN and Starburst Activity: Exploring the interplay between Active Galactic Nuclei (AGN) and star formation processes. I analyze how AGN contributions affect ionization parameters and emission line strengths throughout different evolutionary stages of starburst activity, providing insights into the role AGNs play in galaxy evolution.
  
  

Overall, my research bridges theoretical models with observational data, aiming to significantly enhance our comprehension of galaxy formation, evolution, and the physics of the early universe.

        M.Sc  Project

 Exploring the Topology of Hydrogen Distribution in the Early Universe

Abstract :

The topological distribution of neutral hydrogen (H i) during different stages of the Epoch of Reionization (EoR) can provide us a great wealth of information about the properties of the ionizing sources during this era. In this project, we have used an algorithm, SURFGEN2 on a suite of simulated H i 21-cm maps from the EoR to characterize the evolution of the shape and size of the largest ionized region in these maps. This specific method of characterizing any field is known as tracing the Largest Cluster Statistics (LCS). We perform a comparative study of the LCS of ionized regions for six different simulated reionization scenarios. Our study reveals that the shape of the LCS of ionized regions and hence their topology varies significantly in all six cases. Particularly the global neutral fraction at which percolation between all ionized regions occur is different for different reionization scenarios. Further, we find that LCS of ionized regions is a robust statistic that can differentiate between the fundamentally inside-out and outside-in reionization scenarios. The neutral fractions at which the percolation takes place for inside-out and outside-in reionization varies considerably from each other. The analysis done in this project is going to be particularly useful for analysing high resolution 21-cm tomographic maps of the EoR that the highly sensitive upcoming Square Kilometre Array promises to produce in future. These image analysis techniques can potentially be used to constrain the parameters of the EoR from such future 21-cm observations.