scholarly journals A precise mass function in the excursion set approach

2017 ◽  
Vol 26 (1) ◽  
Author(s):  
Antonino Del Popolo
Keyword(s):  
Angular Momentum ◽  
Cosmological Constant ◽  
Mass Range ◽  
Mass Function ◽  
Dynamical Friction ◽  
Spherical Collapse ◽  
Collapse Model ◽  
Virial Mass ◽  
Excursion Set ◽  
Good Agreement

AbstractIn the present paper, using previous results from Del Popolo papers, we show how the mass function evolution can be obtained in the framework of a spherical collapse model, which has been modified to take account of dynamical friction, the cosmological constant, and angular momentum which proto-structures acquire through tidal interaction with neighbouring ones. We found an improved barrier which is in excellent agreement with simulations. The quoted barrier is used to calculated the mass function. In the case of the ΛCDM paradigm, our mass function is in good agreement (within some %) with the mass function of Klypin’s Bolshoi simulation for the virial mass range 5 × 10

IMPROVEMENTS TO THE SPHERICAL COLLAPSE MODEL

2006 ◽  
Vol 15 (07) ◽  
pp. 1067-1088 ◽  
Author(s):  
ANTONINO DEL POPOLO
Keyword(s):  
Cosmological Constant ◽  
Galaxy Formation ◽  
Spherical Model ◽  
Mass Function ◽  
Joint Effect ◽  
Dynamical Friction ◽  
Spherical Collapse ◽  
Theoretical Mass ◽  
Collapse Model ◽  
Tidal Torques

We study the joint effect of dynamical friction, tidal torques and cosmological constant on clusters of galaxy formation. We show that within high-density environments, such as rich clusters of galaxies, both dynamical friction and tidal torques slow down the collapse of low-ν peaks producing an observable variation in the time of collapse of the perturbation and, as a consequence, a reduction in the mass bound to the collapsed perturbation. Moreover, the delay of the collapse produces a tendency for less dense regions to accrete less mass, with respect to a classical spherical model, inducing a biasing of over-dense regions toward higher mass. We show how the threshold of collapse is modified if dynamical friction, tidal torques and a non-zero cosmological constant are taken into account and we use the Extended Press–Schecter (EPS) approach to calculate the effects on the mass function. Then, we compare the numerical mass function given in D. Reed, Mon. Not. R. Astron. Soc.346, 565 (2003) with the theoretical mass function obtained in the present paper. We show that the barrier obtained in the present paper gives rise to a better description of the mass function evolution with respect to other previous models, R. K. Sheth and G. Tormen, Mon. Not. R. Astron. Soc.308, 119 (1999) and R. K. Sheth and G. Tormen, Mon. Not. R. Astron. Soc.329, 61 (2002).

Improvements in the Spherical Collapse Model and Dark Energy Cosmologies

2014 ◽  
Vol 23 (3-4) ◽  
Author(s):  
A. Del Popolo
Keyword(s):  
Shear Stress ◽  
Angular Momentum ◽  
Dark Energy ◽  
Spherical Symmetry ◽  
Linear Density ◽  
Spherical Collapse ◽  
Collapse Model ◽  
Density Threshold ◽  
Stress Influence

AbstractIn the present paper, we study how the effects of deviations from spherical symmetry of a system, produced by angular momentum, and shear stress, influence typical parameters of the spherical collapse model, like the linear density threshold for collapse of the non-relativistic component (

AN IMPROVED MODEL FOR THE MULTIPLICITY FUNCTION

2005 ◽  
Vol 14 (10) ◽  
pp. 1779-1791
Author(s):  
ANTONINO DEL POPOLO
Keyword(s):  
Angular Momentum ◽  
Cosmological Constant ◽  
Total Angular Momentum ◽  
Theoretical Background ◽  
Multiplicity Function ◽  
Excursion Set ◽  
Improved Model ◽  
Function Models

I compare the numerical multiplicity function given in Ref. 35 with the theoretical multiplicity function obtained by means of the excursion set model and an improved version of the barrier shape obtained in Ref. 7, which implicitly takes account of total angular momentum acquired by the proto-structure during evolution and of a non-zero cosmological constant. I show that the multiplicity function obtained in the present paper is in better agreement with the simulations of Yahagi, Nagashima and Yoshii35 than other previous models16,29–31 and that unlike some previous multiplicity function models16,35 it was obtained from a sound theoretical background.

scholarly journals Angular momentum in cluster Spherical Collapse Model

2011 ◽  
Vol 417 (4) ◽  
pp. 2554-2561 ◽  
Author(s):  
Guido Cupani ◽  
Marino Mezzetti ◽  
Fabio Mardirossian
Keyword(s):  
Angular Momentum ◽  
Spherical Collapse ◽  
Collapse Model

scholarly journals EXTENDED SPHERICAL COLLAPSE AND THE ACCELERATING UNIVERSE

2013 ◽  
Vol 22 (08) ◽  
pp. 1350038 ◽  
Author(s):  
A. DEL POPOLO ◽  
F. PACE ◽  
J. A. S. LIMA
Keyword(s):  
Shear Stress ◽  
Angular Momentum ◽  
Linear Density ◽  
Accelerating Universe ◽  
De Sitter ◽  
Local Rotation ◽  
Spherical Collapse ◽  
Collapse Model ◽  
Density Threshold

The influence of the shear stress and angular momentum on the nonlinear spherical collapse model is discussed in the framework of the Einstein–de Sitter and ΛCDM models. By assuming that the vacuum component is not clustering within the homogeneous nonspherical overdensities, we show how the local rotation and shear affect the linear density threshold for collapse of the nonrelativistic component (δc) and its virial overdensity (ΔV). It is also found that the net effect of shear and rotation in galactic scale is responsible for higher values of the linear overdensity parameter as compared with the standard spherical collapse model (no shear and rotation).

scholarly journals LARGE SCALE STRUCTURE BY GLOBAL MONOPOLES AND COLD DARK MATTER

1992 ◽  
Vol 07 (10) ◽  
pp. 903-910 ◽  
Author(s):  
LEANDROS PERIVOLAROPOULOS
Keyword(s):  
Dark Matter ◽  
Cosmological Model ◽  
Gravitational Wave ◽  
Large Scale ◽  
Cold Dark Matter ◽  
Mass Range ◽  
Large Scale Structure ◽  
Mass Function ◽  
Global Monopoles ◽  
Good Agreement

A cosmological model in which the primordial perturbations are provided by global monopoles and in which the dark matter is cold has several interesting features. The model is normalized by choosing its single parameter within the bounds obtained from gravitational wave constraints and by demanding coherent velocity flows of about 600 km/sec on scales of 50h-1 Mpc . Using this normalization, the model predicts the existence of dominant structures with mass 2×1016M⊙ on a scale 35h-1 Mpc , i.e., larger than the horizon at t ep . The magnitude of the predicted mass function in the galactic mass range is in good agreement with the observed Schechter function.

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