JADES: Rest-frame Optical/NIR Size Evolution of Massive Quiescent Galaxies from z=5 to z=0.5

We present the rest-frame optical/NIR size evolution of a sample of 157 massive quiescent galaxies with stellar mass M_* > 10¹⁰ M_sun over the redshift range of 0.5 < z < 5. With deep, high angular resolution NIRCam imaging observations from the GOODS-S portion of the JWST Advanced Deep Extragalactic Survey (JADES), we verify the quiescent nature of these galaxies via SED fitting, and, for the first time, we are able to directly measure the rest-frame optical/NIR size of quiescent galaxies and its evolution beyond z > 2.5. We find that the size evolution, both at the rest-frame 5000A and 1 micron, depends on stellar mass, with more massive quiescent galaxies having a steeper evolution. For lower-mass quiescent galaxies with M_* = 10^10-10.6 M_sun, the size evolution is broadly consistent with (1+z)^-1, suggesting that the sizes of these quiescent galaxies and their dark matter halos grow at a similar pace. For higher-mass quiescent galaxies with M_* > 10^10.6 M_sun, we find a steeper size evolution (than expected simply from dark matter halo growth) following (1+z)^-1.7. Additionally, we see evidence that the scatter in the ratio of size at rest-frame 1 micron divided by it at 5000A increases toward lower redshifts along with this steeper evolution. In addition, at z < 1.5, the higher-mass quiescent galaxies with a disky+spheroidal morphology tend to have a larger size ratio, i.e. they are more extended at 5000A than at 1 micron, relative to those classified as pure spheroids. Taken together, these findings are consistent with the picture that, compared to the lower-mass ones, higher-mass quiescent galaxies after they formed can more efficiently keep growing their sizes through merging with satellite galaxies and continuous gas accretion. Our study highlights the power of JWST’s Infrared imaging capability in constraining the evolution of stellar morphology of quiescent galaxies toward much higher redshifts that were not attainable before.