Title: Probing the mass distribution of dark matter halos with weak lensing analyses

Speaker: Professor Fan Zuhui,Peking University

Location: Room 111, Physics Building

Time: 15:00-16:00p, March 13, 2013

Abstract:

The weak lensing effect has been recognized as an important means in probing the nature of dark matter and dark energy. However, the full realization of its power in cosmological studies relies on our thorough understanding of different systematic effects. In this presentation, I will discuss weak-lensing constraints on the density profile of dark matter halos and consequently the concentration-mass (c-M) relation. We construct mock weak lensing observations with the cluster lens catalog extracted from the Millennium Simulation. Different center identification schemes are explored. We also pay particular attention to the noise effects arising from source intrinsic ellipticities. We find that because of the strong degeneracy between the concentration parameter and the mass of a halo in terms of tangential shear signals, the weak lensing determined c-M relation depends sensitively on the noise level if the halos are grouped into different mass bins based on the weak lensing derived mass, the higher the noise, the steeper the derived c-M relation. Therefore in order to compare the results from weak lensing analyses with theoretical predictions and draw physical conclusions, the noise effects have to be taken into account properly.

Biography:

Zuhui Fan received her Ph.D. degree in physics in 1995 from University of Washington, USA. She then moved to Department of Astronomy and Astrophysics, Univ. of Chicago as a visiting scientist (1996 to 2002). She was a postdoc fellow at ASIAA and National Taiwan University from Sept. 1999 to Feb. 2000. Since June 2002, she has been a professor at Department of Astronomy, Peking University. Her research field is in cosmology and large-scale structures.