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This paper describes a search for galaxy centers with clear indications ofunusual stellar populations with an initial mass function flatter than Salpeterat high stellar masses. Out of a sample of 668 face-on galaxies with stellarmasses in the range 10^10- 10^11 M_sol, I identify 15 galaxies with young tointermediate age central stellar populations with unusual stellar populationgradients in the inner regions of the galaxy. In these galaxies, the 4000Angstrom break is either flat or rising towards the center of the galaxy,indicating that the central regions host evolved stars, but the H$\alpha$equivalent width also rises steeply in the central regions. The ionizationparameter [OIII]/[OII] is typically low in these galactic centers, indicatingthat ionizing sources are stellar rather than AGN. Wolf Rayet featurescharacteristic of hot young stars are often found in the spectra and these alsoget progressively stronger at smaller galactocentric radii. These outliers arecompared to a control sample of galaxies of similar mass with young innerstellar populations, but where the gradients in Halpha equivalent width and4000 Angstrom break follow each other more closely. The outliers exhibitcentral Wolf Rayet red bump excesses much more frequently, they have highercentral stellar and ionized gas metallicities, and they are also morefrequently detected at 20 cm radio wavelengths. I highlight one outlier wherethe ionized gas is clearly being strongly perturbed and blown out either bymassive stars after they explode as supernovae, or by energy injection frommatter falling onto a black hole.

A study of the central stellar populations of galaxies in SDSS-IV MaNGA: identification of a sub-sample with unusually young and massive stars