A kpc-scale resolved study of unobscured and obscured star-formation
  activity in normal galaxies at z = 1.5 and 2.2 from ALMA and HiZELS
  We present Atacama Large Millimeter/Submillimeter Array (ALMA) continuum
observations of a sample of nine star-forming galaxies at redshifts 1.47 and
2.23 selected from the High-$z$ Emission Line Survey (HiZELS). Four galaxies in
our sample are detected at high significance by ALMA at a resolution of 0.25''
at rest-frame 355 $\mu$m. Together with the previously observed H$\alpha$
emission, from adaptive optics-assisted integral-field-unit spectroscopy
(0.15'' resolution), and F606W and F140W imaging from the Hubble Space
Telescope (0.2'' resolution), we study the star-formation activity, stellar and
dust mass in these high-redshift galaxies at $\sim$kpc-scale resolution. We
find that ALMA detection rates are higher for more massive galaxies
($M_*>10^{10.5}$ M$_\odot$) and higher [N {\sc ii}]/H$\alpha$ ratios ($>0.25$,
a proxy for gas-phase metallicity). The dust extends out to a radius of 8 kpc,
with a smooth structure, even for those galaxies presenting clumpy H$\alpha$
morphologies. The half-light radii ($R_{\rm dust}$) derived for the detected
galaxies are of the order $\sim$4.5 kpc, more than twice the size of
submillimetre-selected galaxies at a similar redshift. Our global
star-formation rate estimates -- from far-IR and extinction-corrected H$\alpha$
luminosities -- are in good agreement. However, the different morphologies of
the different phases of the interstellar medium suggest complex extinction
properties of the high-redshift normal galaxies.
