Seminar Series

Subaru Weak lensing Survey of Dark Matter Subhalos in the Coma cluster


Professor Toshi Futamase


Department of Astrophysics and Atmospheric physics, Kyoto Sangyo University, Japan

Time & Place

Fri, 17 Feb 2017 11:00:00 NZDT in Rutherford 531, Level 5

All are welcome


The hierarchical structure formation scenario based on the cold dark matter (CDM) paradigm has been very successful in explaining various cosmological observations such as the large scale distribution of galaxies, and thus became the standard scenario for structure formation. However, there is almost no observational evidence to test it on the Megaparsec (Mpc) scale where mass assembly history becomes important.

We have performed weak lensing observation of COMA cluster at redshift z = 0.027 to test CDM predictions in Mpc scale. We detected convincingly 32 subhalos in a modelindependent manner, down to the order of 10^-3 of the virial mass of the Cluster. Weak lensing mass measurements of shearselected subhalos allow us to investigate subhalo properties and the correlation between subhalo masses and galaxy luminosities for the first time.

The constructed mass function is consistent with the prediction by N-body simulation based on CDM scenario.

In this talk I will give a brief introduction of weak lensing and then show our results and ongoing weak lensing survey of very nearby cluster z < 0.05 using Subaru/HSC.