We present the analysis of Hubble Space Telescope ( HST ) J - and H -band imaging for 29 galaxies on the star-forming main-sequence at z \sim 2 , which have adaptive optics Very Large Telescope SINFONI integral field spectroscopy from our SINS/zC-SINF program .
The SINFONI H \alpha data resolve the ongoing star formation and the ionized gas kinematics on scales of 1 - 2 kpc ; the NIR 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 Sérsic profile with n \sim 1 , with only \sim 15 \% requiring a high n > 3 Sérsic 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 \sim 15 \% showing a substantial bulge-to-total ratio B / T \gtrsim 0.3 .
This is a lower limit to the frequency of z \sim 2 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 and 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 z \sim 2 massive galaxies with \gtrsim 10 ^ { 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 z \sim 2 galaxies being sustained at large galactocentric distances .