相关论文: Spherical collapse and halo mass function in f(R) …
The excursion set approach allows one to estimate the abundance and spatial distribution of virialized dark matter haloes efficiently and accurately. The predictions of this approach depend on how the nonlinear processes of collapse and…
We present a new theory for the hierarchical clustering of dark matter (DM) halos based on stochastic differential equations, that constitutes a change of perspective with respect to existing frameworks (e.g., the excursion set approach);…
We present an analytic formula for the supercluster mass function which is constructed by modifying the extended Zel'dovich model for the halo mass function. The formula has two characteristic parameters whose best-fit values are determined…
The evolution of the virial overdensity $\Delta_{\rm vir}$ for $\Lambda$CDM and seven dynamical dark-energy models is investigated in the extended spherical collapse model (SCM). Here the virialization process is naturally achieved by…
We study the formation of dark matter halos in the concordance LCDM model over a wide range of redshifts, from z=20 to the present. Our primary focus is the halo mass function, a key probe of cosmology. By performing a large suite of…
We generalize the spherical collapse model for the formation of bound objects to apply in a Universe with arbitrary positive cosmological constant. We calculate the critical condition for collapse of an overdense region and give exact…
We study the spherically symmetric gravitational collapse of massless scalar matter field in asymptotic flat spacetime in $f(R)$ gravity. In the Einstein frame of $f(R)$ gravity, an additional scalar field arises due to the conformal…
We study the spherical collapse model (SCM) in the framework of spatially flat power law $f(T) \propto (-T)^{b}$ gravity model. We find that the linear and non-linear growth of spherical overdensities of this particular $f(T)$ model are…
We present "sheet+release" simulations that reliably follow the evolution of dark matter structure at and below the dark matter free-streaming scale, where instabilities in traditional N-body simulations create a large population of…
An important indicator of modified gravity is the effect of the local environment on halo properties. This paper examines the influence of the local tidal structure on the halo mass function, the halo orientation, spin and the…
Non-spherical dynamical approximations and models for the gravitational collapse are used to extend the well-known Press \& Schechter (PS) approach, in order to determine analytical expressions for the mass function of cosmic structures.…
Sheth-Tormen mass function has been widely used to quantify the abundance of dark matter halos. It is a significant improvement over the Press-Schechter mass function as it uses ellipsoidal collapse in place of spherical collapse. Both of…
Simulations of cold dark matter make robust predictions about the slope and normalization of the dark matter halo and subhalo mass functions on small scales. Recent observational advances utilizing strong gravitational lensing have…
The friends-of-friends algorithm (hereafter, FOF) is a percolation algorithm which is routinely used to identify dark matter halos from N-body simulations. We use results from percolation theory to show that the boundary of FOF halos does…
I calculate the mass function evolution in a $\Lambda$CDM model by means of the excursion set model and an improved version of the barrier shape obtained in Del Popolo & Gambera (1998), which implicitly takes account of the total angular…
The hybrid Ricci scalar $R_{\mu\nu}\eta^{\mu\nu}$ formed from a Robertson-Walker derived Ricci tensor and a distinct flat space metric becomes a dark, pseudo-isothermal density under asymptotic constraint. While extension of this constraint…
In this paper we investigate how the halo mass function evolves with redshift, based on a suite of very large (with N_p = 3072^3 - 6000^3 particles) cosmological N-body simulations. Our halo catalogue data spans a redshift range of z =…
We describe how to extend the excursion set peaks framework so that its predictions of dark halo abundances and clustering can be compared directly with simulations. These extensions include: a halo mass definition which uses the TopHat…
The initial state of the spherical gravitational collapse in general relativity has been studied with different methods, especially by using {\it a priori} given equations of state that describe the matter as a perfect fluid. We propose an…
We use the Excursion Set formalism to compute the properties of the halo mass distribution for a stochastic barrier model which encapsulates the main features of the ellipsoidal collapse of dark matter halos. Non-markovian corrections due…