Metallicity gradients in nearby star forming galaxies

I study the gas phase metallicity (O/H) radial profiles in a representative sample of 550 nearby star forming galaxies with resolved spectroscopic data from the SDSS-IV MaNGA survey. Using strong-line ratio diagnostics (R23 and O3N2) and referencing to the effective (half-light) radius (R_e), I find that the metallicity gradient steepens with stellar mass going from log(M_*/M_solar) = 9.0 to log(M_*/M_solar) = 10.5. At higher masses a flattening of the metallicity radial profile is observed in the central regions (R < 1R_e). These findings are in agreement with recent independent analysis of other large samples of nearby galaxies.