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Astronomy Colloquium (2019 Fall Semester)

* Date
Oct. 24
* Speaker
Dr. Jongwan Ko (KASI)
* Title
Finding the origin of intracluster light
* Abstract

Not all stars in the Universe are gravitationally bounded to galaxies. Since first discovered in 1951 (Zwicky 1951), observations have revealed that a significant fraction of stars fills the space between galaxies in local galaxy clusters, observed as diffuse intracluster light (ICL). Theoretical models provide mechanisms for the production of intracluster stars as tidally stripped material or debris generated through numerous galaxy interactions during the hierarchical growth of the galaxy cluster. These mechanisms predict that most intracluster stars in local galaxy clusters are long-accumulated material since z~1, corresponding to an age of the Universe of more than 6 billion years. However, there is no observational evidence to verify this prediction. In this talk, I will report observations of abundant ICL for massive galaxy clusters at z>1, and introduce a KASI project about developing a pathfinder telescope optimized to probe low surface brightness structures such as ICL.