Expanding the boundaries of dark matter halo

Session

Halo Theory: Boundary dynamics

May 26, 2025, 9:00 AM

C204, Student Center (Shanghai Jiao Tong University)

Conveners

Halo Theory: Boundary dynamics

• Surhud More (IUCAA)

Halo Theory: Boundary dynamics

• Surhud More (IUCAA)

50. The depletion radius of dark matter halo

Jiaxin Han (Shanghai Jiao Tong University)

5/26/25, 9:00 AM

Halo Theory: Boundary dynamics

Talk

I will report our recent development of the depletion radius, which is a new but fundamental halo boundary stemming from the macroscopic physics of halo growth. I will show that the depletion radius is both an important physical probe of halo evolution and a concise geometric boundary for halo models of the large scale structure, capable of overcoming major limitations of the classical halo in...

33. The Dependence of Depletion Radius on Mass Accretion Rate

Jiale Zhou (Shanghai Jiao Tong University)

5/26/25, 9:30 AM

Halo Theory: Boundary dynamics

Talk

We determine the depletion radius from the stacked mass flow rate (MFR) profiles of dark matter haloes in a cosmological simulation and explore its dependence on halo properties. We find that the MFR profiles exhibit near self-similarity for haloes with different masses. The primary factor that determines the depletion radius is still the mass accretion rate, and the relation is similar to...

38. Splashback radius as a probe of cosmology and astrophysics

Tae-hyeon Shin (Carnegie Mellon University)

5/26/25, 9:50 AM

Probing cosmology

Talk

Splashback radius is a physically motivated boundary of halos, formed at the first apocenters of orbiting matter. Due to its strong correlation to the recent mass accretion history, especially that over the last one dynamical time, the splashback radius could be used to study the cosmic evolution, as well as astrophysics within halos. In this talk, I will briefly summarize the recent progress...

48. Splashback radius of nonspherical dark matter halos and the cosmological implications

Prof. Teppei Okumura (ASIAA)

5/26/25, 10:45 AM

Halo Theory: Boundary dynamics

Talk

We investigate the splashback features of nonspherical dark-matter halos in phase space, namely based on cosmic density and velocity fields. Besides the density correlation function binned by the halo orientation angle, which was used in the literature, we introduce the corresponding velocity statistic, alignment velocity correlation function, to consider halo's asphericity. Using...

37. The splashback radius and the radial velocity profile of galaxy clusters in IllustrisTNG

Michele Pizzardo (Saint Mary's University)

5/26/25, 11:15 AM

Boundaries in different tracers

Talk

Clusters of galaxies are massive bound systems. At a large radius of 5 Mpc or more, massive clusters of galaxies decouple from the Hubble flow. Within this turnaround radius, galaxies are still accreting onto the cluster in the outer portion, the infall region. In the dense central regions with radii < 2 Mpc, clusters are dynamically relaxed. We use the radial velocity profile of cluster...