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We investigate radial gradients in the recent star formation history (SFH)using 1917 galaxies with $0.01<z<0.14$ and integral-field spectroscopy from theongoing MaNGA survey. For each galaxy, we obtain two-dimensional maps andradial profiles for three spectroscopically-measured parameters that aresensitive to the recent SFH: D$_n$(4000) (the 4000\AA\ break), EW(H$\delta_A$)(equivalent width of the H$\delta$ absorption line), and EW(H$\alpha$)(equivalent width of the H$\alpha$ emission line). We find the majority of thespaxels in these galaxies are consistent with models with continuouslydeclining star formation rate, indicating that starbursts occur rarely in localgalaxies. We classify the galaxies into three classes: fully star-forming (SF),partly quenched (PQ) and totally quenched (TQ), according to the fraction ofquenched area within 1.5 times the effective radius, $f_Q(1.5R_e)$. We findthat galaxies less massive than $10^{10}$M$_{\odot}$ present at most weakradial gradients in all the diagnostic parameters. In contrast, galaxies withstellar mass above $10^{10}$M$_{\odot}$ present significant gradients in allthe three diagnostic parameters if classified as SF or PQ, but show weakgradients in D$_n$(4000) and EW(H$\delta_A$) and no gradients in EW(H$\alpha$)if in the TQ class. This implies the existence of a critical stellar mass, at$\sim10^{10}$M$_{\odot}$, above which the star formation in a galaxy getsshutdown from the inside out. Galaxies tend to evolve synchronously from innerto outer regions before their mass reaches the critical value. We have furtherdivided the sample at fixed mass by both bulge-to-total luminosity ratio andmorphological type, finding that our conclusions hold regardless of thesefactors: it appears that the presence of a central dense object is not adriving parameter, but rather a byproduct of the star formation cessationprocess.

SDSS-IV MaNGA: Star formation cessation in low-redshift galaxies I. Dependence on stellar mass and structural properties