We analyze the recent released HST /WFC3 IR images in the GOODS-N region to study the formation and evolution of Quiescent galaxies ( QGs ) .
After examining the reliability with artificial galaxies , we obtain the morphological parameters with Sérsic profile of 299 QGs and 1,083 star-forming galaxies ( SFGs ) at z \sim 0.5 –3.0 , finding the evolution of r _ { \mathrm { e } } and n of massive ( M _ { * } \geq 10 ^ { 10.5 } M _ { \sun } ) QGs while weaker evolution of SFGs and less massive ( M _ { * } < 10 ^ { 10.5 } M _ { \sun } ) QGs .
The regression of the size evolution of massive QGs follows r _ { \mathrm { e } } \propto ( 1 + z ) ^ { - \alpha _ { r _ { \mathrm { e } } } } with \alpha _ { r _ { \mathrm { e } } } = 1.06 \pm 0.19 ( a factor of \sim 2.2 increase from z \sim 2.5 to \sim 0.5 ) , which is consistent with the general picture of the significant size growth .
For the further understanding of the evolution scenario , we study the evolution of Sérsic index , n , and find that of massive QGs to significantly evolve as n \propto ( 1 + z ) ^ { - \alpha _ { n } } with \alpha _ { n } = 0.74 \pm 0.23 ( n \sim 1 at z \sim 2.5 to n \sim 4 at z \sim 0.5 ) , while those of the other populations are unchanged ( n \sim 1 ) over the redshift range .
The results in the present study are consistent with both of observation and numerical simulations , where gas-poor minor merger is believed to be the main evolution scenario .
By taking account of the connection with less massive QGs and SFGs , we discuss the formation and evolution of the massive QGs over “ Cosmic High Noon ” , or the peak of star-formation in the universe .