Conveners
halo: assembly & clustering
- Jie Wang
halo: assembly & clustering
- Houjun Mo (U. Mass.)
I will talk about different boundaries of a dark matter halo focusing on our recently proposed depletion boundary. I will explain its physics and measurements, and illustrate how this new boundary could help us to gain new insights into halo evolution and to provide much improved description of the cosmic structure.
We develop a self-consistent and accurate halo model by partitioning matter according to the depletion radii of haloes. Unlike conventional models that define haloes with the virial radius while relying on a separate exclusion radius or ad-hoc fixes to account for halo exclusion, our model distributes mass across all scales self-consistently and accounts for both the virialized and...
We propose a novel method to quantify the assembly histories of dark matter halos with the redshift evolution of the mass-weighted spatial variance of their progenitor halos, i.e. the protohalo size history. We find that the protohalo size history for each individual halo at z~0 can be described by a double power-law function. The amplitude of the fitting function strongly correlates to the...
High-resolution N-body simulations have shown that the large-scale clustering of dark halos is predominantly but not purely dependent on their dark matter mass. At fixed halo mass, the bias factor of halo clustering depends on a variety of secondary properties of halos such as formation time, concentration, spin and shape, an effect known as “assembly bias” which should be related to the...
Massive neutrinos have a minimal impact on large-scale structure formation but suppress cosmic growth at small, nonlinear scales. We examine small-scale discrepancies between simulations with and without massive neutrinos from the Quijote simulation. Employing a one-to-one halo matching approach based on the initial peaks of haloes, where the initial positions of cold dark matter particles are...
Recent studies illustrate the correlation between the angular momenta of cosmic structures and their Lagrangian properties. However, only baryons are observable and it is unclear whether they reliably trace the cosmic angular momenta. We study the Lagrangian mass distribution, spin alignment, and conservation of dark matter (DM), gas, and stellar components of galaxy–halo systems using...
Cosmic filaments are one of the most important structures in the universe and have a significant influence on the formation and evolution of galaxies. Research involving both observation and simulation has demonstrated that the direction of a galaxy's spin is associated with the cosmic filament: low-mass galaxies tend to be aligned, while high-mass galaxies are usually perpendicular. However,...
Satellite galaxies tend to occupy the region in between pairs of massive galaxies, as seen in both the Local Group (between the Milky Way and M31) and distant galaxy pairs in SDSS. Possible origins include local gravity between paired halos and the large-scale filamentary environment. We investigate the anisotropic distribution of satellites around pairs of galaxy groups in SDSS/DR7 as well as...
