천문우주과학과

일시:  2022년 3월 10일 목요일 오후 4시 세미나실(자4514호)
         (https://cnu-ac-kr.zoom.us/j/2677604561) 

연사:  윤용민 박사님(고등과학원)

제목: Effects of Cluster/Galaxy Mergers on Galaxy Properties

 초록:  

  In this talk, two subjects are presented. One is about the observational evidence that bars in disk galaxies can form by cluster-cluster interaction and the bar formation is associated with star formation enhancement, which is found by analyzing the Sloan Digital Sky Survey (SDSS) data. Specifically, I show that barred disk galaxy fraction is about 1.5 times higher in interacting clusters than in clusters with no obvious signs of interaction (42% versus 27%). For disk galaxies with 10.0<logM_star<10.4, the bar formation is accompanied by enhancement of star formation, so that the fraction of star-forming galaxies is about 1.2 times higher in interacting clusters than in non-interacting clusters. The other subject is about the impact of galaxy mergers on properties of early-type galaxies (ETGs), such as age, internal structure, and stellar kinematics (e.g., specific angular momentum within the half-light radius λ_R). This study is based on MaNGA integral field unit spectroscopic data and deep coadded images of the Stripe 82 region of SDSS for the detection of tidal features that are direct evidence for recent mergers. The main results show that tidal features are more frequent in younger and more compact ETGs and ETGs with dust lanes, which suggests that those ETGs are involved in recent mergers. In addition, λ_R is lower in ETGs with tidal features than in those without tidal features, in the case of ETGs that do not have dust lanes, which indicates that galaxy mergers can generally lower the angular momentum of ETGs.