ALMA obs. of UDS and GOODS-S massive galaxies

We present 0.2 resolution Atacama Large Millimeter/submillimeter Array (ALMA) observations at 870um in a stellar mass-selected sample of 85 massive (M*>10^11^M_{sun}_) star-forming galaxies (SFGs) at z=1.9-2.6 in the CANDELS/3D-Hubble Space Telescope fields of UDS and GOODS-S. We measure the effective radius of the rest-frame far-infrared (FIR) emission for 62 massive SFGs. They are distributed over wide ranges of FIR size from R_e,FIR_=0.4kpc to R_e,FIR_=6kpc.

The effective radius of the FIR emission is smaller by a factor of 2.3_-1.0_^+1.9^ than the effective radius of the optical emission and is smaller by a factor of 1.9_-1.0_^+1.9^ than the half-mass radius. Taking into account potential extended components, the FIR size would change only by ~10%. By combining the spatial distributions of the FIR and optical emission, we investigate how galaxies change the effective radius of the optical emission and the stellar mass within a radius of 1kpc, M_1kpc_.