Name: Himansh Rathore
Affiliation: Indian Institute of Technology Bombay
Conference ID : ASI2022_543
Title : Star-forming S0 Galaxies in SDSS-MaNGA: Fading Spirals Or Rejuvenated S0s?
Authors : Himansh Rathore (IIT Bombay), Kavin Kumar (IISER Bhopal), Preetish K. Mishra (NCRA Pune, IUCAA Pune), Yogesh Wadadekar (NCRA Pune), Omkar Bait (NCRA Pune, Université de Genève)
Abstract Type: Poster
Abstract Category : Extragalactic Astronomy
Abstract : S0 galaxies are generally expected to be quenched in star-formation. Yet, there exists an exceptional class of actively star-forming S0s in the nearby universe. Studying such galaxies is of paramount importance to understand the complex processes governing galaxy evolution. They could be spirals which are fading into the red sequence and are experiencing a last burst of star-formation along with transformation to a S0 morphology. Likewise, they could be a quenched population of S0s that has been rejuvenated in star-formation. We studied a sample of nearby (z < 0.1) star-forming S0 (SF-S0) galaxies in the SDSS-MaNGA Integral Field Spectroscopic survey, with the goal of understanding their star-formation properties and evolutionary history on both global and resolved scales. For this, we also constructed control samples of star-forming spirals (SF-Sps) and quenched S0s (Q-S0s), whose properties are compared to the main sample of SF-S0s. We constructed radial profiles of star-formation rate (SFR) surface density and specific SFR and concluded that SF-S0s possess centrally dominated star-formation as opposed to disc dominated star-formation in SF-Sps. We compared global properties like the size-mass relation, bulge-to-total light ratio and local properties like central velocity dispersion of the three samples, and inferred that SF-S0s are structurally similar to Q-S0s and hence are not fading spirals. Thus, star-formation in our sample of SF-S0s has likely been rejuvenated. We inspected stellar and gas kinematic maps of SF-S0s and realized that more than 50% of them show disturbed kinematics indicative of recent interactions. Hence, we conclude that gas rich minor mergers are the most likely cause for rejuvenated star-formation in our sample of SF-S0s.