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With the advent of large scale galaxy surveys, constraints on primordial non-Gaussianity (PNG) are expected to reach ${\cal O}(f_\text{NL}) \sim 1$. In order to fully exploit the potential of these future surveys, a deep theoretical…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-16 Matteo Biagetti , Vincent Desjacques

We derive an estimate of the rate of formation of dark matter halos per unit volume as a function of the halo mass and redshift of formation. Analytical estimates of the number density of dark matter halos are useful in modeling several…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-30 Sourav Mitra , Girish Kulkarni , J. S. Bagla , Jaswant K. Yadav

We revisit the derivation of the mass function and the bias of dark matter halos for non-Gaussian initial conditions. We use a steepest-descent approach to point out that exact results can be obtained for the high-mass tail of the halo mass…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 P. Valageas

We present a stochastic approach to the spatial clustering of dark matter haloes in Lagrangian space. Our formalism is based on a local formulation of the `excursion set' approach by Bond et al., which automatically accounts for the…

Astrophysics · Physics 2009-10-30 Cristiano Porciani , Sabino Matarrese , Francesco Lucchin , Paolo Catelan

We study structure formation in the presence of primordial non-Gaussianity of the local type with parameters f_NL and g_NL. We show that the distribution of dark-matter halos is naturally described by a multivariate bias scheme where the…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-14 Tommaso Giannantonio , Cristiano Porciani

The galactic scale challenges of dark matter such as "missing satellite" problem and "too big to fail" problem are the main caveats of standard model of cosmology. These challenges could be solved either by implementing the complicated…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-14 Hamed Kameli , Shant Baghram

If one accounts for correlations between scales, then nonlocal, k-dependent halo bias is part and parcel of the excursion set approach, and hence of halo model predictions for galaxy bias. We present an analysis that distinguishes between a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Marcello Musso , Aseem Paranjape , Ravi K. Sheth

The excursion set theory of halo formation is modified by adopting the fractional Brownian motion, to account for possible correlation between merging steps. We worked out analytically the conditional mass function, halo merging rate and…

Astrophysics · Physics 2009-11-13 Jun Pan , Yougang Wang , Xuelei Chen , Luis Teodoro

We present an algorithm for generating merger histories of dark matter haloes. The algorithm is based on the excursion set approach with moving barriers whose shape is motivated by the ellipsoidal collapse model of halo formation. In…

Astrophysics · Physics 2009-01-03 Jorge Moreno , Carlo Giocoli , Ravi K. Sheth

The L\'evy walk process for the lower interval of the time of flight distribution ($\alpha<1$) and with finite resting time between consecutive flights is discussed. The motion is restricted to a region bounded by two absorbing barriers and…

Statistical Mechanics · Physics 2023-07-19 A. Kamińska , T. Srokowski

In the Excursion Set approach, halo abundances and clustering are closely related. This relation is exploited in many modern methods which seek to constrain cosmological parameters on the basis of the observed spatial distribution of…

Cosmology and Nongalactic Astrophysics · Physics 2012-02-23 Aseem Paranjape , Ravi K. Sheth

We have revisited the extended excursion set theory in modified gravity models, taking the chameleon model as an example. Instead of specifying their Lagrangian size, here we define the environments by the Eulerian size, chosen to be of the…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-24 Baojiu Li , Tsz Yan Lam

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

Analytic models based on spherical and ellipsoidal gravitational collapse have been used to derive the mass functions of dark matter halos and their progenitors (the conditional mass function). The ellipsoidal model generally provides a…

Astrophysics · Physics 2010-12-16 Jun Zhang , Chung-Pei Ma , Onsi Fakhouri

The ConflUent System of Peak trajectories (CUSP) is a rigorous formalism in the framework of the peak theory that allows one to derive from first principles andno free parameters the typical halo properties from the statistics of peaks in…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-17 Eduard Salvador-Solé , Alberto Manrique

Aims. We aim to study the stochastic evolution of the smoothed overdensity $\delta$ at scale $S$ of the form $\delta(S) = \int_{0}^S K(S,u)\mathrm{d}W(u)$, where $K$ is a kernel and $\mathrm{d}W$ is the usual Wiener process. Methods. For a…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-23 Nicos Hiotelis , Antonino Del Popolo

The fractional Brownian motion with index $\alpha$ is introduced to construct the fractional excursion set model. A new mass function with single parameter $\alpha$ is derived within the formalism, of which the Press-Schechter mass function…

Astrophysics · Physics 2009-11-11 Jun Pan

We examine the mean first passage time for a particle driven by highly correlated Gaussian fluctuations to reach one or more predetermined boundaries. We discuss a numerical algorithm to generate power-law correlated fluctuations and apply…

Statistical Mechanics · Physics 2007-05-23 Aldo H. Romero , J. M. Sancho , Katja Lindenberg

We calculate crossing probabilities and one-sided last exit time densities for a class of moving barriers on an interval $[0,T]$ via Schwartz distributions. We derive crossing probabilities and first hitting time densities for another class…

Probability · Mathematics 2008-08-28 Nabil Kahale

A method is proposed to select the suitable sets of potential parameters for a one-dimensional mesoscopic Hamiltonian model, first introduced to describe the DNA melting transition and later extended to investigate thermodynamic and…

Soft Condensed Matter · Physics 2020-12-09 Marco Zoli