Abstract Details
| Name: Prerana Biswas Affiliation: Post Doctoral fellow Conference ID: ASI2025_430 Title : Unravelling the kinematics, dynamics and structure of galaxies using HI - 21cm observation Authors and Co-Authors : Dr. Nirupam Roy 1, Dr. Narendra Nath Patra 2, Dr. Veselina Kalinova 3, Md Rashid 4 Abstract Type : Oral Abstract Category : Thesis Abstract : Several HI-21cm interferometric observations of nearby galaxies in recent decades have comprised a large dataset. To assess the completeness, coverage of these sources and potential of archival data, we created a sample of 515 galaxies from GMRT (Giant Meterwave Radio Telescope) archive, focusing on good-quality HI spectral line data. We plan to analyse this data uniformly to explore different science cases through the GMRT ARChIve Atomic gas survey (GARCIA), starting with an analysis of a pilot sample of eleven galaxies. With the pilot sample, we first identified warm and cold phases in ISM through Multi-Gaussian decomposition method. Our method distinguishes different phases at a lower SNR of 5, unlike previous studies that were limited to SNR 10 or above, enabling better detection of cold gas in outskirts and warm gas in central regions. Further, we present 3D kinematical models of these galaxies by fitting Tilted-ring model to 3-dimensional data cubes and build a robust technique for galaxy mass modelling. For the first time, we combined 3D modelled rotation curve, stellar kinematics derived using Multi-Gaussian Expansion technique and Jeans Anisotropic Modelling, our own-developed method for gas contribution; for doing mass modelling via MCMC optimisation method. Additionally, we investigated kinematic and morphological lopsidedness of galaxies and checked consistency between morphological and kinematic halo perturbation parameters derived from 3D kinematic modelling, unlike previous studies. Moreover, our robust modelling techniques are further applied to a larger number of sources from CALIFA survey, allowing us to revisit Baryonic Tully-Fisher relation, where we observed an indication of a shallower slope. These studies, initially on pilot samples, will be extended to data-products from future batches of GARCIA. Beside that, in upcoming era of large interferometers like Square Kilometer Array (SKA), archival visibility data will facilitate revisiting raw data, applying improved calibration techniques, and exploring new algorithms. |