SDSS-IV MaNGA: Inside-out vs. outside-in quenching in different local
  environments
  The large Integral Field Spectroscopy (IFS) surveys have allowed the
classification of ionizing sources of emission lines on sub-kpc scales. In this
work, we define two non-parametric parameters, quiescence (f$_{q}$) and its
concentration (c$_{q}$), to quantify the strength and the spatial distribution
of the quenched areas, respectively, traced by the LI(N)ER regions with low
EW(H$\alpha$). With these two measurements, we classify MaNGA galaxies into
inside-out and outside-in quenching types according to their locations on the
f$_{q}$ vs. c$_{q}$ plane and we measure the fraction of inside-out
(outside-in) quenching galaxies as a function of halo mass. We find that the
fraction of galaxies showing inside-out quenching increases with halo mass,
irrespective of stellar mass or galaxy type (satellites vs. centrals). In
addition, high stellar mass galaxies exhibit a greater fraction of inside-out
quenching compared to low stellar mass ones in all environments. In contrast,
the fraction of outside-in quenching does not depend on halo mass. Our results
suggest that morphological quenching may be responsible for the inside-out
quenching seen in all environments. On the other hand, the flat dependence of
the outside-in quenching on halo mass could be a mixed result of ram-pressure
stripping and galaxy mergers. Nevertheless, at a given environment and stellar
mass, the fraction of inside-out quenching is systematically greater than that
of outside-in quenching, suggesting that inside-out quenching is the dominant
quenching mode in all environments.
