Using state-of-the-art adaptive mesh refinement cosmological hydrodynamic simulations with a spatial resolution of 0.15 h-1kpc on a cosmological volume (20 h-1Mpc), we investigate the sizes of galaxies at z=3 in the standard cold dark matter model where re

Fig.1.—Thelargeimagedisplaystheprojectedstellarmassdensityofaregionofcomovingsize(1.0h 1Mpc)2withadepthofcomoving2.4h 1Mpcatz=3,cutoutfromoneofoursimulationvolumes.Theinsetszoominonthefourmostmassivegalaxiesinvolumeregionintermsofvirialmassandshowtheirprojectedluminositydensitydistributions.Foreachgalaxy,theimagesshow,fromlefttoright,intrinsic(beforedustattenuationisapplied),apparent(afterdustattenuation),andsmoothed(afterdustattenuationandPSF ltering)luminositydensities,respectively,allintheobservedg′-band.Thebarsindicatelengthsinproperkpc.