Dust attenuation, bulge formation and inside-out cessation of
  star-formation in Star-Forming Main Sequence galaxies at z~2
  We derive two-dimensional dust attenuation maps at $\sim1~\mathrm{kpc}$
resolution from the UV continuum for ten galaxies on the $z\sim2$ Star-Forming
Main Sequence (SFMS). Comparison with IR data shows that 9 out of 10 galaxies
do not require further obscuration in addition to the UV-based correction,
though our sample does not include the most heavily obscured, massive galaxies.
The individual rest-frame $V$-band dust attenuation (A$_{\rm V}$) radial
profiles scatter around an average profile that gently decreases from $\sim1.8$
mag in the center down to $\sim0.6$ mag at $\sim3-4$ half-mass radii. We use
these maps to correct UV- and H$\alpha$-based star-formation rates (SFRs),
which agree with each other. At masses $<10^{11}~M_{\rm sun}$, the
dust-corrected specific SFR (sSFR) profiles are on average radially constant at
a mass-doubling timescale of $\sim300~\mathrm{Myr}$, pointing at a synchronous
growth of bulge and disk components. At masses $>10^{11}~M_{\rm sun}$, the sSFR
profiles are typically centrally-suppressed by a factor of $\sim10$ relative to
the galaxy outskirts. With total central obscuration disfavored, this indicates
that at least a fraction of massive $z\sim2$ SFMS galaxies have started their
inside-out star-formation quenching that will move them to the quenched
sequence. In combination with other observations, galaxies above and below the
ridge of the SFMS relation have respectively centrally-enhanced and
centrally-suppressed sSFRs relative to their outskirts, supporting a picture
where bulges are built due to gas `compaction' that leads to a high central SFR
as galaxies move towards the upper envelope of SFMS.
