紅移值1或更遠的星系團內星系之演化


Colloquium: The Evolution of Galaxies in Clusters at z~1 and Beyond 
 
Galaxy clusters provide a large range of environments for the study of how the environment affects galaxy evolution. I will present some recent results on the evolution of galaxies in clusters at z~1 and beyond from two large cluster surveys. SpARCS is an imaging survey designed to search for galaxy clusters up to z~2 using the cluster red-sequence technique based on a combination of Spitzer Space Telescope’s IRAC 3.6um and ground-based z’-band images; GLASS is a multi-object spectroscopic survey of 10 of the richest SpARCS clusters at z~1 using the Gemini 8.2m telescopes. Analysis of GCLASS data show that galaxies in-falling into clusters at z~1 have their star formation suppressed in a relatively short time scale of less than 0.5 Gyr at an average location close to 0.5 r_200 (the cluster-centric radius within which the cluster is largely virialized). From imaging data obtain using the 24um MIPS camera on Spitzer, we also find that lower-mass in-falling galaxies show a possible last-gasp increase in their star formation before become quiescent. We will take a detailed look at the change in star formation in in-falling galaxies in 3 clusters at z~1.2, by examining their dust emission using far-IR/submm data from the Herschel Space Telescope. 
 
時間:2016.02.23(二) 16:00
地點:香港大學 莊月明物理樓 522室
講者:Prof. Howard K.C. YEE 余光超 教授 (Department of Astronomy and Astrophysics, University of Toronto) 
語言:英語

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