相关论文: Gravitational collapse in an expanding background …
We study the gravitational collapse of an overdensity of nonrelativistic matter under the action of gravity and a chameleon scalar field. We show that the spherical collapse model is modified by the presence of a chameleon field. In…
Small non-spherical perturbations of a spherically symmetric but time-dependent background spacetime can be used to model situations of astrophysical interest, for example the production of gravitational waves in a supernova explosion. We…
Halo mergers and shock waves play a crucial role in the process of hierarchical clustering. Hydrodynamical simulations are the principal investigation tool in this field for theoreticians, and predict that a by-product of cluster formation…
This work is directed towards investigating the fate of three-dimensional long perturbation waves in a plane incompressible wake. The analysis is posed as an initial-value problem in space. More specifically, input is made at an initial…
When a bubble of air rises to the top of a highly viscous liquid, it forms a dome-shaped protuberance on the free surface. Unlike a soap bubble, it bursts so slowly as to collapse under its own weight simultaneously, and folds into a…
As an idealized model of the effects of energy release by supernovae during galaxy formation, we consider an explosion at the center of a halo which forms at the intersection of filaments in the plane of a cosmological pancake by…
We investigate the gravitational effect of large-scale radiation perturbations on small-scale structure formation. In addition to making the growth of matter perturbations scale dependent, the free-streaming of radiation also affects the…
We develop a novel approach in exploring the joint dependence of halo bias on multiple halo properties using Gaussian process regression. Using a $\Lambda$CDM $N$-body simulation, we carry out a comprehensive study of the joint bias…
We investigate the effects of halo ellipticity and alignment with larger-scale structure on the galaxy correlation function. We base our analysis on the galaxy formation models of Guo et al. (2011), run on the Millennium Simulations. We…
The morphological nature of structures that form under gravitational instability has been of central interest to cosmology for over two decades. A remarkable feature of large scale structures in the Universe is that they occupy a relatively…
The effect of halo substructures on galaxy rotation curves is investigated in this paper using a simple model of dark matter clustering. A dark matter halo density profile is developed based only on the scale free nature of clustering that…
We study turbulence in self-gravitating superfluids by performing direct numerical simulations of the 3D Gross-Pitaevskii-Poisson (GPP) equation, which is also a model for dark matter haloes around galaxies. In the absence of self-gravity,…
We examine the scale dependence of dark matter, halo and galaxy clustering on very large scales (0.01<k[h/Mpc]<0.15), due to non-linear effects from dynamics and halo bias. We pursue a two line offensive: high resolution numerical…
We intend to understand cosmological structure formation within the framework of superfluid models of dark matter with finite temperatures. Of particular interest is the evolution of small-scale structures where the pressure and superfluid…
The power spectrum response function of the large-scale structure of the Universe describes how the evolved power spectrum is modified by a small change in initial power through non-linear mode coupling of gravitational evolution. It was…
Waves and shocks traveling through the solar chromospheric plasma are influenced by its partial ionization and weak collisional coupling, and may become susceptible to multi-fluid effects, similar to interstellar shock waves. In this study,…
Jeans showed analytically that, in an infinite uniform-density isothermal gas, plane-wave perturbations collapse to dense sheets if their wavelength, $\lambda$, satisfies $\lambda > \lambda_{_{\rm JEANS}} = (\pi a^2 / G \rho_{_0})^{1/2}$…
The dynamics of small-scale structures in free-surface turbulence is crucial to large-scale phenomena in natural and industrial environments. Here we conduct experiments on the quasi-flat free surface of a zero-mean-flow turbulent water…
The nonlinear collapse for viscous generalized Chaplygin gas Model (VGCG) was analyzed in the framework of spherical top-hat collapse. As the VGCG and baryons are essential to form the large scale structure, we focused on their nonlinear…
The next-to-minimal supersymmetric standard model predicts the formation of domain walls due to the spontaneous breaking of the discrete $Z_3$-symmetry at the electroweak phase transition, and they collapse before the epoch of big bang…