We present the analysis of HST $J$- and $H$-band imaging for 29 galaxies on the star-forming main sequence at $zsim2$, which have Adaptive Optics VLT SINFONI integral field spectroscopy from our SINS/zC-SINF program. The SINFONI H$alpha$ data resolve the on-going star-formation and the ionized gas kinematics on scales of $1-2$ kpc; the near-IR images trace the galaxies rest-frame optical morphologies and distributions of stellar mass in old stellar populations at a similar resolution. The global light profiles of most galaxies show disk-like properties well described by a single Sersic profile with $nsim1$, with only $sim15%$ requiring a high $n>3$ Sersic index, all more massive than $10^{10}M_odot$. In bulge+disk fits, about $40%$ of galaxies have a measurable bulge component in the light profiles, with $sim15%$ showing a substantial bulge-to-total ratio $B/Tge0.3$. This is a lower limit to the frequency of $zsim2$ massive galaxies with a developed bulge component in stellar mass because it could be hidden by dust and/or outshined by a thick actively star-forming disk component. The galaxies rest-optical half-light radii range between $1-7$ kpc, with a median of 2.1 kpc, and lie slightly above the size-mass relation at these epochs reported in the literature. This is attributed to differences in sample selection and definitions of size and/or mass measurements. The $(u-g)_{rest}$ color gradient and scatter within individual $zsim2$ massive galaxies with $ge10^{11}M_odot$ are as high as in $z=0$ low-mass, late-type galaxies, and are consistent with the high star-formation rates of massive $zsim2$ galaxies being sustained at large galactocentric distances.
تحميل البحث