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Building upon [2308.02636], we investigate the constraining power of persistent homology on cosmological parameters and primordial non-Gaussianity in a likelihood-free inference pipeline utilizing machine learning. We evaluate the ability…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-22 Juan Calles , Jacky H. T. Yip , Gabriella Contardo , Jorge Noreña , Adam Rouhiainen , Gary Shiu

In numerical relativity simulations with non-trivial matter configurations, one must solve the Hamiltonian and momentum constraints of the ADM formulation for the metric variables in the initial data. We introduce a new scheme based on the…

General Relativity and Quantum Cosmology · Physics 2023-03-15 Josu C. Aurrekoetxea , Katy Clough , Eugene A. Lim

The effects of particle discreteness in N-body simulations of Lambda Cold Dark Matter (LambdaCDM) are still an intensively debated issue. In this paper we explore such effects, taking into account the scatter caused by the randomness of the…

Astrophysics · Physics 2009-11-13 Alessandro B. Romeo , Oscar Agertz , Ben Moore , Joachim Stadel

We investigate cosmological constraints on K-mouflage models of modified gravity. We consider two scenarios: one where the background evolution is free to deviate from $\Lambda$CDM (K-mouflage) and another one which reproduces a…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-29 Giampaolo Benevento , Marco Raveri , Andrei Lazanu , Nicola Bartolo , Michele Liguori , Philippe Brax , Patrick Valageas

The halo assembly bias, a phenomenon referring to dependencies of the large-scale bias of a dark matter halo other than its mass, is a fundamental property of the standard cosmological model. First discovered in 2005 from the Millennium Run…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-19 Yen-Ting Lin , Hironao Miyatake , Hong Guo , Yi-Kuan Chiang , Kai-Feng Chen , Ting-Wen Lan , Yu-Yen Chang

The phenomenon of the very local ($\le3$ Mpc) Hubble flow is studied on the basis of the data of recent precision observations. A set of computer simulations is performed to trace the trajectories of the flow galaxies back in time to the…

We study how well perturbative forward modeling can constrain cosmological parameters compared to conventional analyses. We exploit the fact that in perturbation theory the field-level posterior can be computed analytically in the limit of…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-31 Giovanni Cabass , Marko Simonović , Matias Zaldarriaga

We present a new technique for constraining the topology of the universe. The method exploits the existence of correlations in the phases of the spherical harmonic coefficients of the CMB temperature pattern associated with matched pairs of…

Astrophysics · Physics 2009-11-10 Patrick Dineen , Graca Rocha , Peter Coles

Methods of dynamical systems have been used to study homogeneous and isotropic cosmological models with a varying speed of light (VSL). We propose two methods of reduction of dynamics to the form of planar Hamiltonian dynamical systems for…

General Relativity and Quantum Cosmology · Physics 2008-07-22 Marek Szydlowski , Adam Krawiec

In the paper, we present an accelerating cosmological model in $f(R,\mathcal{L}_{m})$ gravity with the parameter constrained through the cosmological data sets. At the beginning, we have employed a functional form of $f(R,\mathcal{L}_{m})…

General Relativity and Quantum Cosmology · Physics 2025-01-10 Y. Kalpana Devi , S. A. Narawade , B. Mishra

In this paper, a cosmological model of the Universe is presented in $f(Q,T)$ gravity and the parameters are constrained by cosmological data sets. Initially, a generalised form of $f(Q,T)$ model is used as $f(Q,T)=-\lambda_{1}…

General Relativity and Quantum Cosmology · Physics 2024-03-21 A. S. Agrawal , B. Mishra , S. K. Tripathy

Hydrodynamical simulations are the most accurate way to model structure formation in the universe, but they often involve a large number of astrophysical parameters modeling subgrid physics, in addition to cosmological parameters. This…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-05 Benjamin Horowitz , Zarija Lukic

Gravitational lensing has become one of the most powerful tools available for investigating the 'dark side' of the universe. Cosmological strong gravitational lensing, in particular, probes the properties of the dense cores of dark matter…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-30 Nan Li , Michael D. Gladders , Esteban M. Rangel , Michael K. Florian , Lindsey E. Bleem , Katrin Heitmann , Salman Habib , Patricia Fasel

The detailed nature of dark energy remains a mystery, leaving the possibility that its effects might be explained by changes to the laws of gravity on large scales. The peculiar velocities of galaxies directly trace the strength of gravity…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-29 Stuart Lyall , Chris Blake , Ryan J. Turner

We develop a machine learning approach to reconstructing the cosmological initial conditions from late-time dark matter halo number density fields in redshift space, with the goal of improving sensitivity to cosmological parameters, and in…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-15 Jelte Bottema , Thomas Flöss , P. Daniel Meerburg

We propose a new approach for multiverse analysis based on computational complexity, which leads to a new family of "computational" measure factors. By defining a cosmology as a space-time containing a vacuum with specified properties (for…

High Energy Physics - Theory · Physics 2018-04-18 Frederik Denef , Michael R. Douglas , Brian Greene , Claire Zukowski

A valuable amount of information is available in peculiar velocities of galaxies. Peculiar velocity surveys have recently allowed the discovery of potential problems with LCDM. Nonetheless, their direct observation through distance…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 G. Lavaux

We compare the structural properties and dark matter content of star-forming galaxies taken from the CAMELS cosmological simulations to the observed trends derived from the SPARC sample in the stellar mass range $[10^{9},…

We present cosmological parameter constraints from the SFI++ galaxy peculiar velocity survey, the largest galaxy peculiar velocity sample to date. The analysis is performed by using the gridding method developed in Abate et al. (2008). We…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Alexandra Abate , Pirin Erdogdu

Numerical simulation plays an important role in the study of structure formation of the universe. However, the mass resolution in current simulations is still poor. Due to technical difficulties, it is necessary to use both greatly reduced…

Astrophysics · Physics 2009-11-10 Weike Xiao , Zhengfan Sun , Heng Hao