Title: Cosmic velocity field detected by the kinetic Sunyaev Zel’dovich effect

Speaker: Yi Zheng（郑逸）

Abstract: With the next generation of cosmic surveys (both LSS and CMB), the kinetic Sunyaev Zel’dovich (kSZ) effect will serve as an important cosmic probe, providing us the information of the cosmic structure growth history and the baryon distribution in the universe. Out of numerous estimators for the kSZ effect detection, I will focus on the widely adopted pairwise estimator in this talk. By developing a phenomenological model for the pairwise kSZ power spectrum, I will show how the f-tau_T degeneracy, which is a long-standing problem in the kSZ cosmology, can be spontaneously broken by the non-linear structure formation. As a result, the kSZ effect can be complementary in the gravity test on the cosmological scales, as I will show through analysis with modified gravity simulations. I will also present a preliminary measurement of the pairwise kSZ power spectrum from DESI and Planck data. The detection significance is around 4.5\sigma. Finally, I will focus on a special vorticity filed in the universe: the overall rotation of a cosmic filament. The existence and origin of this kind of rotation are under debate. Its kSZ effect detection can serve as an independent evidence. I will discuss how this kind of rotation can be detected by kSZ effects if it exists. The detection signal-to-noises of future surveys will be presented, and its cosmological application will be briefly discussed.

Reference:  2001.08608, 2209.04464, Xiao&Zheng in preparation, Li&Zheng in preparation

Speaker bio:

Yi Zheng, graduated from Shanghai astronomical observatory as a PhD, ever worked as a Postdoc in KASI and KIAS in Korea, is now an associated professor in the School of Physics and Astronomy, Sun Yat-Sen University. His main research field is  the peculiar velocity cosmology. He has been always working on alleviating different systematic errors in the modelling of the redshift space distortion effect and the kinetic Sunyaev Zel’dovich effect. He is also trying to measure these effects from real data recently.

Time:10:00-11:00AM, 9/Nov, Wednesday

Tencent Meeting link:  https://meeting.tencent.com/dm/z1HnOuAgiFPC

Meeting ID: 360-1536-1663

Password: 2022

Video Link: https://vshare.sjtu.edu.cn/play/ce5c41678e5c21cf00ed4b3a68040c84