We perform dry merger simulations to investigate the role of dry mergers in the size growth of early-type galaxies in high density environments .
We replace the virialized dark matter haloes obtained by a large cosmological N -body simulation with N -body galaxy models consisting of two components , a stellar bulge and a dark matter halo , which have higher mass resolution than the cosmological simulation .
We then re-simulate nine cluster forming regions , whose masses range from 1 \times 10 ^ { 14 } \mathrm { M } _ { \odot } to 5 \times 10 ^ { 14 } \mathrm { M } _ { \odot } .
Masses and sizes of stellar bulges are also assumed to satisfy the stellar mass–size relation of high-z compact massive early-type galaxies .
We find that dry major mergers considerably contribute to the mass and size growth of central massive galaxies .
One or two dry major mergers double the average stellar mass and quadruple the average size between z = 2 and z = 0 .
These growths favorably agree with observations .
Moreover , the density distributions of our simulated central massive galaxies grow from the inside-out , which is consistent with recent observations .
The mass–size evolution is approximated as R \propto M _ { * } ^ { \alpha } , with \alpha \sim 2.24 .
Most of our simulated galaxies are efficiently grown by dry mergers , and their stellar mass–size relations match the ones observed in the local Universe .
Our results show that the central galaxies in the cluster haloes are potential descendants of high-z ( z \sim 2-3 ) compact massive early-type galaxies .
This conclusion is consistent with previous numerical studies which investigate the formation and evolution of compact massive early-type galaxies .