Past Events

Abstract

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.

About the Speaker

Prof. Howard Yee received his Bachelor's degree in Engineering Science from University of Toronto and his PhD in Astronomy from the California Institute of Technology. After holding postdoctoral positions at University of Arizona and Herzberg Institute of Astrophysics, he was a University Research Fellow at Universite de Montreal, before joining the Department of Astronomy and Astrophysics (DAA) at University of Toronto as a faculty member. He was the Chair of the Department between 2010 and 2015. Professor Yee has worked in a number of fields in optical/IR observational extragalactic astronomy, including the environments of quasars, redshift surveys of both cluster and field galaxies, and large imaging surveys for finding high-redshift galaxy clusters. He held the Canada Research Chair for Observational Cosmology from 2002 to 2015, and is a Fellow of the Royal Society of Canada.

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Physics colloquium series is organized to introduce cutting edge researches and new development in physics, designed to be suitable to graduate and undergraduate students, and also to scientists working on different fields. Each colloquium will generally start with an extensive introduction of the background of the field, followed by forefront research topics and results. The colloquium will serve as an education forum for students and laymen alike, and also serve as a platform for exchange and update their knowledge of various branches of physics among academic staff members.

Coffee and tea will be served 20 minutes prior to the colloquium.
Anyone interested is welcome to attend.