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We show how the excursion set moving barrier model for halo abundances may be generalized to the local non-Gaussian f_{nl} model. Our estimate assumes that the distribution of step sizes depends on f_{nl}, but that they are otherwise…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Tsz Yan Lam , Ravi K. Sheth

The excursion set model provides a convenient theoretical framework to derive dark matter halo abundances. This paper generalizes the model by introducing a more realistic merging and collapse process. A new parameter regulates the…

Astrophysics · Physics 2009-11-10 Grigori Amosov , Peter Schuecker

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…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-29 P. S. Corasaniti , I. Achitouv

Constrained realisations of Gaussian random fields are used in cosmology to design special initial conditions for numerical simulations. We review this approach and its application to density peaks providing several worked-out examples. We…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-06 Cristiano Porciani

We estimate the halo mass function (HMF) by applying the excursion set approach to the non-linear cosmic density field. Thereby, we account for the non-Gaussianity of today's density distribution and constrain the HMF independent of the…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-25 Laila Linke , Johannes Schwinn , Matthias Bartelmann

In attempts to explain dark energy, a number of models have been proposed in which the formation of large-scale structure depends on the local environment. These models are highly non-linear and difficult to analyse analytically. N-body…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-04 Baojiu Li , George Efstathiou

In excursion set theory the computation of the halo mass function is mapped into a first-passage time process in the presence of a barrier, which in the spherical collapse model is a constant and in the ellipsoidal collapse model is a fixed…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-18 Michele Maggiore , Antonio Riotto

We derive approximated, yet very accurate analytical expressions for the abundance and clustering properties of dark matter halos in the excursion set peak framework; the latter relies on the standard excursion set approach, but also…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 A. Lapi , L. Danese

We apply the model relating halo concentration to formation history proposed by Ludlow et al. to merger trees generated using an algorithm based on excursion set theory. We find that while the model correctly predicts the median relation…

Astrophysics of Galaxies · Physics 2019-03-20 Andrew J. Benson , Aaron Ludlow , Shaun Cole

Recent analytical work on the modelling of dark halo abundances and clustering has demonstrated the advantages of combining the excursion set approach with peaks theory. We extend these ideas and introduce a model of excursion set peaks…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-14 Emanuele Castorina , Aseem Paranjape , Oliver Hahn , Ravi K. Sheth

We use group size haloes identified with a ``friends of friends'' (FOF) algorithm in a concordance $\Lambda \rm{CDM}$ GADGET2 (dark matter only) simulation to investigate the dependence of halo properties on the environment at $z=0$. The…

Astrophysics · Physics 2008-11-26 Cinthia Ragone-Figueroa , Manolis Plionis

The excursion set approach is a framework for estimating how the number density of nonlinear structures in the cosmic web depends on the expansion history of the universe and the nature of gravity. A key part of the approach is the…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-31 Farnik Nikakhtar , Mohammadreza Ayromlou , Shant Baghram , Sohrab Rahvar , M. Reza Rahimi Tabar , Ravi K. Sheth

We discuss two slightly counter-intuitive findings about the environmental dependence of clustering in the Sloan Digital Sky Survey. First, we find that the relation between clustering strength and density is not monotonic: galaxies in the…

Astrophysics · Physics 2008-11-26 Ummi Abbas , Ravi K. Sheth

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…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-31 Jiaxin Han , Yin Li , Yipeng Jing , Takahiro Nishimichi , Wenting Wang , Chunyan Jiang

N-body simulations have demonstrated a correlation between the properties of haloes and their environment. In this paper, we assess whether the ellipsoidal collapse model can produce a similar dependence. First, we explore the statistical…

Astrophysics · Physics 2009-11-13 Vincent Desjacques

Relying on the excursion set theory, we compute the number density of local extrema and crossing statistics versus the threshold for the stock market indices. Comparing the number density of excursion sets calculated numerically with the…

Statistical Finance · Quantitative Finance 2022-07-08 M. Shadmangohar , S. M. S. Movahed

Recently, we provided a simple but accurate formula which closely approximates the first crossing distribution associated with random walks having correlated steps. The approximation is accurate for the wide range of barrier shapes of…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-09 Marcello Musso , Ravi K. Sheth

(Abridged) We study the outer density profiles of dark matter haloes predicted by a generalized secondary infall model and observed in a N-body cosmological simulation of a \Lambda CDM model. We find substantial systematic variations in…

Astrophysics · Physics 2009-10-31 V. Avila-Reese , C. Firmani , A. Klypin , A. V. Kravtsov

Excursion set theory is a powerful and widely used tool for describing the distribution of dark matter haloes, but it is normally applied with simplifying approximations. We use numerical sampling methods to study the mass functions…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-29 M. Sten Delos

The Press--Schechter, excursion set approach allows one to make predictions about the shape and evolution of the mass function of bound objects. It combines the assumption that objects collapse spherically with the assumption that the…

Astrophysics · Physics 2008-11-26 Ravi K. Sheth , H. J. Mo , Giuseppe Tormen