The Wavelength Dependence of High-Redshift Galaxy Structure in the
  Rest-Frame Ultraviolet
  We present the rest-frame UV wavelength dependence of the Petrosian-like
half-light radius ($r_{50}$), and the concentration parameter for a sample of
198 star-forming galaxies at 0.5 < z < 1.5. We find a ~5% decrease in $r_{50}$
from 1500 \AA\ to 3000 \AA, with half-light radii at 3000 \AA\ ranging from 0.6
kpc to 6 kpc. We also find a decrease in concentration of ~0.07 (1.9 <
$C_{3000}$ < 3.9). The lack of a strong relationship between $r_{50}$ and
wavelength is consistent with a model in which clumpy star formation is
distributed over length scales comparable to the galaxy's rest-frame optical
light. While the wavelength dependence of $r_{50}$ is independent of size at
all redshifts, concentration decreases more sharply in the far-UV (~1500 \AA)
for large galaxies at z ~ 1. This decrease in concentration is caused by a
flattening of the inner ~20% of the light profile in disk-like galaxies,
indicating that the central regions have different UV colors than the rest of
the galaxy. We interpret this as a bulge component with older stellar
populations and/or more dust. The size-dependent decrease in concentration is
less dramatic at z ~ 2, suggesting that bulges are less dusty, younger, and/or
less massive than the rest of the galaxy at higher redshifts.
