Collaboration Workshop on Cosmology and Galaxy Formation

Transport mechanisms in the intracluster medium

Jun 23, 2023, 10:00 AM

20m

Hengli Hotel

Talk Gas Gas

Speaker

一纬 张 (云南大学中国西南天文研究所)

Description

Recently, the high metallicity in the outskirts of galaxy clusters has been puzzling and asks for a deeper investigation of the transport mechanisms in the intracluster medium (ICM). We studied the transport mechanisms in the ICM using tracer particle re-simulation of the Omega500 cosmological hydrosimulation, and focused on the particle transport during major mergers. We used pair dispersion statistics to study the effect of particle transport at various epochs of the cluster assembly history. In a system filled with Kolmogorov turbulence, the squared displacement of particles is described by the ‘super-diffusion’ Richardson scaling $$ ~ $t^{3/2}$, in contrast to $$ ~ $t$ for the standard diffusion process. We found that pair dispersion follows the Richardson scaling during the major merger stage, but is slower before or after it. This means that the transport process in the ICM does not follow a universal law, but depends on the evolution period of galaxy clusters. We looked for possible coherent transport during the major merger, and found it to be subdominant compared to turbulence. Turbulence strength is the underlying reason of the varying pair dispersion behavior: while strong turbulence is excited at the major merger, it quickly decays afterwards.

Presentation materials

suzhou0623zhangyiwei.pdf