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In this study, we employ dynamical systems methods to analyse the large-scale structure by considering two distinct interaction models (linear and non-linear) within the dark sector, associated with a specific dynamical dark energy model…

General Relativity and Quantum Cosmology · Physics 2026-02-02 Dumiso Mithi , Saikat Charkraborty , Shambel Sahlu , Amare Abebe

Stellar dynamical modeling is a powerful method to determine the mass of black holes in quiescent galaxies. However, in previous work the presence of a dark matter halo has been ignored in the modeling. Gebhardt & Thomas (2009) showed that…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Andreas Schulze , Karl Gebhardt

We study non-linear structure formation in an interacting model of the dark sector of the Universe in which the dark energy density decays linearly with the Hubble parameter, $\rho_{\Lambda} \propto H$, leading to a constant-rate creation…

Cosmology and Nongalactic Astrophysics · Physics 2015-02-09 N. Chandrachani Devi , H. A. Borges , S. Carneiro , J. S. Alcaniz

Recent observations suggest that the accelerated expansion of the Universe at late times is caused by a temporally changing dark energy component, rather than the constant one in the standard $\Lambda$CDM scenario. In this context…

General Relativity and Quantum Cosmology · Physics 2025-11-05 Artur Alho , Elsa Bernholm , Claes Uggla

We calculate the multiplicity function of matter condensations by directly considering the actual, deeply non-linear density field, which we compare to the popular Press-Schechter approximation. We show the mass function is a function of a…

Astrophysics · Physics 2007-05-23 Patrick Valageas , Richard Schaeffer

We present a simple model that accurately describes various statistical properties of peculiar velocities of dark matter halos. We pay particular attention to the following two effects; first, the evolution of the halo peculiar velocity…

Astrophysics · Physics 2009-11-07 Takashi Hamana , Issha Kayo , Naoki Yoshida , Yasushi Suto , Y. P. Jing

While the $\Lambda$CDM model succeeds on large scales, its validity on smaller scales remains uncertain. Recent works suggest that non-halo dark matter structures, such as filaments and walls, could significantly influence gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-21 Baptiste Jego , Giulia Despali , Tamara Richardson , Jens Stücker

We propose a two parameters extension of the flat $\Lambda$CDM model to capture the impact of matter inhomogeneities on our cosmological inference. Non virialized but non-linearly evolving overdense and underdense regions, whose abundance…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-11 Leonardo Giani , Rodrigo Von Marttens , Ryan Camilleri

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…

Astrophysics · Physics 2008-11-26 A. Del Popolo

We study structure formation in a set of cosmological simulations to uncover the scales in the initial density field that gave rise to the formation of present-day structures. Our simulations share a common primordial power spectrum (here…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-22 Till Sawala , Adrian Jenkins , Stuart McAlpine , Jens Jasche , Guilhem Lavaux , Peter H. Johansson , Carlos S. Frenk

We have studied the nonlinear structure formation of the environmentally dependent dilaton model using $N$-body simulations. We find that the mechanism of suppressing the scalar fifth force in high-density regions works very well. Within…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-04 Phil Brax , Carsten van de Bruck , Anne-C. Davis , Baojiu Li , Douglas J. Shaw

Modern cosmological inference increasingly relies on differentiable models to enable efficient, gradient-based parameter estimation and uncertainty quantification. Here, we present a novel approach for predicting the abundance of dark…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-08 Jim Buisman , Florian List , Oliver Hahn

We present astrophysical applications of the recently popular halo model to describe large scale structure clustering. We formulate the power spectrum, bispectrum and trispectrum of dark matter density field in terms of correlations within…

Astrophysics · Physics 2007-05-23 Asantha Cooray

We study the non-linear gravitational collapse of dark matter into halos through numerical N-body simulations of Lemaitre-Tolman-Bondi void models. We extend the halo mass function formalism to these models in a consistent way. This…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-02 David Alonso , Juan García-Bellido , Troels Haugboelle , Alexander Knebe

On the one hand, the large scale structure of matter is arguably scale invariant, and, on the other hand, halos and voids are recognized as prominent features of that structure. To unify both approaches, we propose to model the dark matter…

Astrophysics · Physics 2008-11-26 Jose Gaite

Based on the work of ratio gravity developed in 2018, which postulates the deformation of the cross ratio to associate with the physical model of gravity, we develop a mechanism to generate dynamical dark energy - a quintessence field…

General Relativity and Quantum Cosmology · Physics 2022-02-25 Jackie C. H. Liu

Dark matter (DM) self-interactions have important implications for the formation and evolution of structure, from dwarf galaxies to clusters of galaxies. We study the dynamics of self-interacting DM via a light mediator, focusing on the…

High Energy Physics - Phenomenology · Physics 2013-06-12 Sean Tulin , Hai-Bo Yu , Kathryn M. Zurek

The nature of dark matter (DM) is still under intense debate. Sub-galactic scales are particularly critical, as different, currently viable DM models make diverse predictions on the expected abundance and density profile of DM haloes on…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-21 Nick Loudas , Vasiliki Pavlidou , Carolina Casadio , Kostas Tassis

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…

Astrophysics · Physics 2008-11-26 Zarija Lukic , Katrin Heitmann , Salman Habib , Sergei Bashinsky , Paul M. Ricker

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
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