SDSS-IV MaNGA: A Star Formation–Baryonic Mass Relation at Kiloparsec Scales

Abstract

Abstract Star formation rate density, ΣSFR, has shown a remarkable correlation with both components of the baryonic mass kiloparsec scales (i.e., the stellar mass density and molecular gas mass density, Σ* and Σmol, respectively) for galaxies in the nearby universe. In this study, we propose an empirical relation between ΣSFR and the baryonic mass surface density (Σb = Σmol,Av + Σ*, where Σmol,Av is the molecular gas derived from the optical extinction, A V ) at kiloparsec scales using the spatially resolved properties of the MaNGA survey, the largest sample of galaxies observed via integral field spectroscopy (∼8400 objects). We find that ΣSFR tightly correlates with Σb. Furthermore, we derive an empirical relation between ΣSFR and a second-degree polynomial of Σb, yielding a one-to-one relation between these two observables. Both Σb and its polynomial form show a stronger correlation and smaller scatter with respect to ΣSFR than the relations derived using the individual components of Σb. Our results suggest that these three parameters are indeed physically correlated, suggesting a scenario in which the two components of the baryonic mass regulate the star formation activity at kiloparsec scales.