We present the near-infrared high resolution imaging of an extremely dense group of galaxies at the core of the protocluster at z = 3.09 in the SSA22 field by using the adaptive optics AO188 and the Infrared Camera and Spectrograph ( IRCS ) on Subaru Telescope .
Wide morphological variety of them suggests their on-going dramatic evolutions .
One of the two quiescent galaxies ( QGs ) , the most massive one in the group , is a compact elliptical with an effective radius r _ { e } = 1.37 \pm 0.75 kpc .
It supports the two-phase formation scenario of giant ellipticals today that a massive compact elliptical is formed at once and evolves in the size and stellar mass by series of mergers .
Since this object is a plausible progenitor of a brightest cluster galaxy ( BCG ) of one of the most massive clusters today , it requires strong size ( \ga 10 ) and stellar mass ( \sim four times by z = 0 ) growths .
Another QG hosts an AGN ( s ) and is fitted with a model composed from an nuclear component and Sérsic model .
It shows spatially extended [ O III ] \lambda 5007 emission line compared to the continuum emission , a plausible evidence of outflows .
Massive star forming galaxies ( SFGs ) in the group are two to three times larger than the field SFGs at similar redshift .
Although we obtained the K -band image deeper than the previous one , we found no candidate new members .
This implies a physical deficiency of low mass galaxies with stellar mass M _ { \star } \la 4 \times 10 ^ { 10 } ~ { } M _ { \odot } and/or poor detection completeness of them owing to their diffuse morphologies .