CANDELS: From Outside-in to Inside-in Quenching of Galaxies at Intermediate z

主讲人 (Speaker): 刘凤山

主讲人单位 (Speaker's Institute): 沈阳师范大学

邀请人 (Invited by): 林伟鹏

时间 (Time): 星期四, 2018/05/17 - 14:30 to 15:00

地点 (Location): 珠海校区海滨红楼17栋107会议室

摘要 (Abstract):

Studying the spatial distribution of specific star formation rate (sSFR) is helpful to understand how stellar mass is build up in galaxies as they evolve along the star-forming main sequence (SFMS), and how and where the star formation shuts down as galaxies move off the SFMS to become fully quiescent.

In this talk, I will give a review of our recent work on the galaxy quenching mode at intermediate redshift, based on a large sample of ~4400 galaxies at at 0.5<z<1 in all five CANDELS fields. We find that at low masses (M_{\ast} < 10^{10}M_{\odot}) SFGs both above and below the SFMS ridge generally have flat sSFR profiles, whereas the transition galaxies at the same masses generally have sSFRs that are more suppressed in their outskirts. In contrast, at high masses (M_{\ast} > 10^{10.5}M_{\odot}), SFGs above and below the SFMS ridge and transition galaxies generally have varying degrees of more centrally-suppressed sSFRs relative to their outskirts. These findings indicate that at z=0.5-1 the main galaxy quenching mode depends on its already formed stellar mass, exhibiting a transition from "the outside-in" to "the inside-out". Our findings support that internal processes dominate the quenching of massive galaxies, whereas external processes dominate the quenching of low-mass galaxies.

主讲人简介 (Speaker's CV):

刘凤山，男，1979年6月生，中共党员。2008年1月在中科院国家天文台获得天体物理学博士学位；2008年4月以“人才引进”方式加盟沈阳师范大学，2012年9月—2014年8月在美国加州大学圣克鲁兹分校从事博士后研究；2014年12月破格晋升为正教授。研究领域为多波段天文观测与数据处理、星系天文学，具体包括：光学红外天文观测、多波段天文数据处理、高红移星系、星系团及其成员星系、低面亮度星系等。目前研究兴趣为HST和JWST数据处理、高红移星系的多波段观测性质。近些年在高红移星系的结构与演化、星系团的搜寻与证认、星系团中最亮成员星系的形成等方面做出了多项重要研究成果，多次赴美、欧、日、韩天文研究机构进行交流访问并建立起广泛地国际合作关系。