Dr. Saili K. Keshri

The formation and evolution of galactic bulges remains a central problem in understanding the growth of disc galaxies, as bulges display a wide range of structural and stellar population properties that reflect multiple formation pathways. Bulges are typically separated into two main classes: classical bulges and disc-like (pseudo-)bulges. Nuclear discs, characterised by their disc-like morphology and exponential light profiles, have historically been called disc-like bulges. In this talk, I will explore how stellar bars and environmental processes shape the central regions of galaxies across different morphologies and environments. Using 4000 Å break strength (Dn(4000)) and the HdA absorption index, we find evidence for an age bimodality among pseudo-bulges in spiral barred galaxies, while barred lenticular galaxies predominantly host old, quenched bulges. Interestingly, most of these old-bulge systems reside in high-density environments, suggesting that bar-driven secular evolution initiates the quenching process, with environmental effects accelerating the transition from young to older, quenched bulges. I will discuss nuclear discs in the central regions of a sample of nearby interacting barred galaxies identified from MUSE data and find a positive correlation between nuclear disc size and bar length. This supports a scenario in which large-scale bars regulate the extent of central mass assembly, while tidal interactions influence the available gas supply and the efficiency of subsequent secular evolution. Together, these results highlight the coupled roles of internal bar-driven processes and external environmental effects in shaping the structural and stellar population properties of galactic bulges and nuclear discs.