2021/06/11(Fri)     11:00 -12:00    Video Seminar


Studying dark matter distribution of galaxy cluster through gravitational lensing


Dr. Sut Ieng Tam

Institute of Astronomy and Astrophysics, Academia Sinica


Galaxy clusters are the largest and rarest structures in our Universe. Their properties depend on the growth of structure from the seeds provided by primordial density fluctuations. Clusters are therefore ideally suited to testing cosmological models. Approximately 80% of a cluster’s mass consists of dark matter. Although this component is invisible, the total mass along a line of sight can be mapped through measurement of the deflection of light from background objects by gravitational lensing. In this talk, I will first show several methods that astronomers constrain dark matter properties by observing galaxy clusters. Secondly, I will present a combined strong + weak lensing and X-ray analysis of a galaxy cluster, MS-0451. This comprehensive study allows us to map the distribution of dark matter throughout a ∼6 × 6 Mpc2 area and constrain some fundamental cluster properties, such as total dark matter halo mass, concentration and its dynamical state.