Star formation (SF) is a hierarchical process in space & time. Supersonic turbulence in the GMCs causes them to fragment into scale-free, hierarchical density structures. These structures collapse during the SF process & the new-born stellar matter inherits the hierarchical structuring of the GMCs. GMC observations in the Milky Way point towards a universality in the hierarchical structuring of molecular gas but stellar distributions in external galaxies deviate from such universality & instead show a dependence on large-scale galaxy properties. So, we first explore the stellar matter hierarchy in 4 nearby spiral galaxies using 1.5” resolution FUV+NUV data from the UltraViolet Imaging Telescope. By employing two-point statistics, we find that young star forming clumps (SFCs) in galaxies are arranged in a hierarchical distribution but this hierarchy is only observable till a maximum scale of kpc order & does not extend to the entire galaxy size (arXiv:2412.00872v2). Hierarchical SF can be sustained up to these scales by turbulence originating from sources like feedback, various instabilities & shocks. As the SFCs migrate away from their parent GMCs due to galactic dynamics, the SFC hierarchy dissipates over 10-50 Myr. We find that the hierarchical nature of SF is not universal & it depends on the nature of spiral arms, stellar mass, environment & shear. Next, to explore how feedback from young, massive stars affects hierarchical SF & whether the hierarchy of molecular gas & SFCs is retained by the ionized gas, we study the HII region distribution in nearby galaxies. This reveals that HII regions show only mild signs of being part of a hierarchy which implies that feedback has a strong, detrimental impact on the hierarchical organization of gas around SFing regions. Through these projects which I will elucidate in my talk, we are investigating the role of turbulence, feedback & environment on the SF process & trying to better understand the baryon cycle in galaxies.
