Research activities include EoR galaxies, UV luminosity function, clumps, star-formation, galaxy growth and galaxy formation.

I am working on different aspects of the AUDF-north field. We are preparing the FUV and NUV photometric source catalog of the AUDF-north field utilizing deep UVIT observations. The key aim is to explore rest-frame FUV properties of galaxies between redshift ~ 0 – 1.0. The superior quality of the AUDF data has helped us to efficiently detect fainter galaxies. Combining the measurements from our catalog and the HST archive, we are studying the rest-frame UV spectral slope of galaxies between z ~ 0.4 – 0.75. The aim is to understand the nature of dust extinction in galaxies at this epoch. I am also looking for Lyc leaking galaxies at intermediate redshift in the AUDF-north field to understand the process of cosmic re-ionization.

My work involving the AUDF data primarily focuses on understanding the low mass galaxy assembly and their evolution over cosmic time. Star-forming low-mass galaxies at intermediate redshifts serve as excellent analogs to understand the early growth of galaxies in the young Universe – the FUV observations indicating activity over the past ~100 Myrs. With deep observations aided by UVIT’s resolution we are trying to understand the nature of low density star-formation at intermediate redshifts. Based on AUDF data, we have recently obtained observational evidence of ongoing mass assembly in a sample of Blue Compact Dwarf (BCD) galaxies. We find that these galaxies host Extended Far-Ultraviolet emission and massive star-forming clumps of a few million solar masses beyond their optical boundaries. These massive clumps are estimated to migrate towards the inner regions via dynamical friction within a billion years timescale, thereby building up the central concentration that we see in today’s BCDs. Torques resulting from such massive stellar or gaseous clumps can funnel in the outer cold gas to fuel the inner parts of the galaxy.

I am currently using UVIT images to probe the hydrogen ionizing spectrum of high-redshift star-forming galaxies in the GOODS-South. The ionizing radiation from such galaxies is thought to be responsible for the process of reionization of neutral hydrogen in the universe, which took place when the universe was just a billion years old. In my efforts to constrain the amount of hydrogen ionizing radiation that escapes high-redshift galaxies, I carry out the spectral-energy distribution modeling of galaxies using archival and UVIT data, stacking analyses, and modeling of the interstellar medium within galaxies. In a collaborative effort with other members of the AUDF group, I am involved in the construction of the UVIT GOODS-South catalog and the development of codes for the background refinement of UVIT images.

My work primarily revolves around spatially extended and clumpy galaxies in the high-z universe. I am working towards how this kind of galaxy morphology forms and evolves as the universe ages to the present epoch and what they become? With the help of AUDF imaging data, we can constrain the various observational properties of galaxies at an extensive range in high-z. As most distant galaxies have low surface brightness, the improved sensitivity of AUDF data compared to previous UV telescopes also helps probe these faint objects. Also, due to better PSF of the AUDF images, it gives us more room for photometry with less flux contamination due to nearby objects. I am also working with other team members to construct a catalog of AUDF-South. My primary work will be focused on studying the evolution and assembly of irregular-shaped extended galaxies at high redshifts.

I am using AstroSat UV Deep Field Goods-south images to look at the clumps of disk galaxies in their early stages of formation. These clumps are high star-forming regions and form due to fragmentation of disk at places of local gravitational instability and with time, they migrate towards the galactic centre playing a role in the central bulge evolution. In my work, I’ll be probing the initial stellar population distribution of clumps in UV disks from UVIT and archival data. I am also involved in the construction of the UVIT Goods-south catalog, and the development of codes for the detection of very faint sources in a collaborative effort with other members of the AUDF group.

High redshift emission-line galaxies, emission line morphology of galaxies, ISM properties of LyC leakers, star-forming ellipticals, star formation quenching in galaxies.