SDSS-IV MaNGA: The Spatial Distribution of Star Formation and its
  Dependence on Mass, Structure and Environment
  We study the spatially resolved star formation of 1494 galaxies in the
SDSSIV-MaNGA Survey. SFRs are calculated using a two-step process, using
$H_\alpha$ in star forming regions and $D_n4000$ in regions identified as
AGN/LI(N)ER or lineless. The roles of secular and environmental quenching
processes are investigated by studying the dependence of the radial profiles of
specific star formation rate on stellar mass, galaxy structure and environment.
We report on the existence of `Centrally Suppressed' galaxies, which have
suppressed SSFR in their cores compared to their disks. The profiles of
centrally suppressed and unsuppressed galaxies are distibuted in a bimodal way.
Galaxies with high stellar mass and core velocity dispersion are found to be
much more likely to be centrally suppressed than low mass galaxies, and we show
that this is related to morphology and the presence of AGN/LI(N)ER like
emission. Centrally suppressed galaxies also display lower star formation at
all radii compared to unsuppressed galaxies. The profiles of central and
satellite galaxies are also compared, and we find that satellite galaxies
experience lower specific star formation rates at all radii than central
galaxies. This uniform suppression could be a signal of the stripping of hot
halo gas in the process known as strangulation. We find that satellites are not
more likely to be suppressed in their cores than centrals, indicating that the
core suppression is an entirely internal process. We find no correlation
between the local environment density and the profiles of star formation rate
surface density.
