Abstract Details

Name: Abhishek Paswan
Affiliation: IUCAA
Conference ID: ASI2020_561
Title : Spectro-photometric Studies of Star-forming Galaxies
Authors and Co-Authors : Abhishek Paswan, Amitesh Omar
Abstract Type : Oral
Abstract Category : Thesis
Abstract : Galaxy formation and evolution is one of the most important issues in modern astrophysics. Galaxies evolve through formation of stars and their consequential effects. The evolution is also affected by several factors such as interactions or merger with other galaxies, environmental effects and feedback processes from AGN. In order to obtain a complete picture and test the theories of galaxy formation and evolution, galaxies in various stages and conditions need to be explored observationally in greater details. In this thesis, we have chosen two different samples of star-forming galaxies across the Hubble types - late-type galaxies (LTGs; spirals, irregulars and dwarfs) and early- type galaxies (ETGs; ellipticals and lenticulars), representing various evolutionary stages of galaxies over cosmic time. These samples are unique in the sense that the selected LTGs are Wolf-Rayet (WR) galaxies known to harbour very young (< 10 Myr old) star-forming regions and the selected ETGs are extremely blue galaxies with very high star formation rates (SFRs; 0.5 – 20 M_sun /yr), unlike normal ETGs which are mainly seen as quiescent galaxies. We constrained SFRs in galaxies and investigated that tidal interactions and/or merger of galaxies or HI clouds are most likely mechanisms for triggering star formation across all the Hubble types of galaxies. Metallicity variations within the galaxies were used to infer chemical evolution due to recent star formation and tidal interactions. In ETGs, we could estimate magnetic fields and star formation rates using radio data. Our finding supports that AGN feedback plays an important role in regulating star formation in massive starburst galaxies. On the other hand, low mass dwarf galaxies are likely to sustain a low level of star formation over long periods of time with occasional starburst, most likely triggered by tidal encounters.