Nature of H-alpha selected galaxies at z>2. II. Clumpy galaxies and
  compact star-forming galaxies
  We present the morphological properties of 109 H\alpha-selected galaxies at
z>2 in SXDF-UDS-CANDELS field. With high-resolution optical/near-infrared
images obtained by Hubble Space Telescope, we identify giant clumps within the
H\alpha emitters (HAEs). We find that at least 41% of our sample show clumpy
structures in the underlying disks. The color gradient of clumps is commonly
seen in the sense that the clumps near the galactic center tend to be redder
than those in the outer regions. The mid-infrared detection in galaxies with
red clumps and the spatial distribution of H\alpha emission suggest that dusty
star-formation activity is probably occurring in the nuclear red clumps. A gas
supply to a bulge component through the clump migration is one of the most
potent physical processes to produce such dusty star-forming clumps and form
massive bulges in local early-type galaxies. They would become large quiescent
galaxies at later times just by consumption or blowout of remaining gas. Also,
while most of the HAEs have extended disks, we observe two massive, compact
HAEs, whose stellar surface densities are significantly higher. They are likely
to be the direct progenitors of massive, compact quiescent galaxies at
z=1.5-2.0. Two evolutionary paths to massive quiescent galaxies are devised to
account for both the size growth of quiescent galaxies and their increased
number density from z~2 to z=0.
