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Related papers: Machine Learning and Structure Formation in Modifi…

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Lagrangian algorithms to simulate the evolution of cold dark matter (CDM) are invaluable tools to generate large suites of mock halo catalogues. In this paper, we first show that the main limitation of current semi-analytical schemes to…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-04 Federico Tosone , Mark C. Neyrinck , Benjamin R. Granett , Luigi Guzzo , Nicola Vittorio

The observed accelerated expansion of the Universe may be explained by dark energy or the breakdown of general relativity (GR) on cosmological scales. When the latter case, a modified gravity scenario, is considered, it is often assumed…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-04 Jiro Matsumoto , Teppei Okumura , Misao Sasaki

We study Modified Gravity (MG) theories by modelling the redshifted matter power spectrum in a spherical Fourier-Bessel (sFB) basis. We use a fully non-linear description of the real-space matter power-spectrum and include the lowest-order…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-27 Dipak Munshi , Geraint Pratten , Patrick Valageas , Peter Coles , Philippe Brax

The morphological properties of large scale structure of the Universe can be fully described by four Minkowski functionals (MFs), which provide important complementary information to other statistical observables such as the widely used…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-24 Wenjuan Fang , Baojiu Li , Gong-Bo Zhao

Deviations from the standard $\Lambda$CDM model motivate an interpretation of early universe cosmology using the Scalar-Tensor-Vector-Gravity (STVG) theory. A constraint analysis carried out by Valentino, Melchiorri and Silk, revealed…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-27 J. W. Moffat

As cosmology rapidly approaches the data-dominated phase of stage IV large scale structure surveys, the modelling of nonlinear scales has become a serious challenge that faces the community, particularly when analysing models beyond $w$CDM.…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-14 Sankarshana Srinivasan , Shreya Prabhu , Kai Lehman , Ajiv Krishnan V. , Jochen Weller

Many theories of modified gravity, including the well studied Horndeski models, are characterized by a screening mechanism that ensures that standard gravity is recovered near astrophysical bodies. In a recently introduced class of…

General Relativity and Quantum Cosmology · Physics 2015-06-11 Ryo Saito , Daisuke Yamauchi , Shuntaro Mizuno , Jérôme Gleyzes , David Langlois

New corrections to General Relativity are considered in the context of modified $f(R)$ gravity, that satisfy cosmological and local gravity constraints. The proposed models behave asymptotically as $R-2\Lambda$ at large curvature and show…

General Relativity and Quantum Cosmology · Physics 2022-01-13 L. N. Granda

The reconstruction scheme is developed for modified $f(R)$ gravity with realistic matter (dark matter, baryons, radiation). Two versions of such theory are constructed: the first one describes the sequence of radiation and matter…

High Energy Physics - Theory · Physics 2008-11-26 Shin'ichi Nojiri , Sergei D. Odintsov

We use cosmological hydrodynamical simulations to study the effect of screened modified gravity models on the mass estimates of galaxy clusters. In particular, we focus on two novel aspects: (i) we study modified gravity models in which…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-21 Max Gronke , A. Hammami , David F. Mota , Hans A. Winther

We study structure formation in phenomenological models in which the Friedmann equation receives a correction of the form $H^{\alpha}/r_c^{2-\alpha}$, which realize an accelerated expansion without dark energy. In order to address structure…

Astrophysics · Physics 2009-11-11 Kazuya Koyama

The measurement of the size of gravitationally bounded structures is an important test of gravity theories. For a given radius different theories can in fact predict a different gravitational stability mass (GSM) necessary to ensure the…

General Relativity and Quantum Cosmology · Physics 2020-06-18 Camilo Santa , Antonio Enea Romano

A major aim of cosmological surveys is to test deviations from the standard $\Lambda$CDM model, but the full scientific value of these surveys will only be realised through efficient simulation methods that keep up with the increasing…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-06 Yash Gondhalekar , Sownak Bose , Baojiu Li , Carolina Cuesta-Lazaro

Machine learning models can be used to predict physical quantities like homogenized elasticity stiffness tensors, which must always be symmetric positive definite (SPD) based on conservation arguments. Two datasets of homogenized elasticity…

Machine Learning · Computer Science 2022-03-29 Charles F. Jekel , Kenneth E. Swartz , Daniel A. White , Daniel A. Tortorelli , Seth E. Watts

We study the linear and nonlinear structure formation in the dilaton and symmetron models of modified gravity using a generic parameterisation which describes a large class of scenarios using only a few parameters, such as the coupling…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Philippe Brax , Anne-Christine Davis , Baojiu Li , Hans A. Winther , Gong-Bo Zhao

We perform a validation of estimates of the growth rate of structure, described by the parameter combination $f\sigma_8$, in modified gravity cosmologies. We consider an analysis pipeline based on the redshift-space distortion modelling of…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-08 Alexandre Barreira , Ariel G. Sánchez , Fabian Schmidt

We study the effect of modifications to General Relativity on large scale weak lensing observables. In particular, we consider three modified gravity scenarios: f(R) gravity, the DGP model, and TeVeS theory. Weak lensing is sensitive to the…

Astrophysics · Physics 2008-11-26 Fabian Schmidt

We discuss the galaxy clustering based on thermodynamics and statistical mechanics in the expanding universe in a modified theory of gravity. The modified general relativity (MGR) is developed using the regular line element field to…

General Physics · Physics 2023-02-15 Abdul W. Khanday , Sudhaker Upadhyay , Prince A. Ganai

We present a random forest framework for predicting circumgalactic medium (CGM) physical conditions from quasar absorption line observables, trained on a sample of Voigt profile-fit synthetic absorbers from the Simba cosmological…

Astrophysics of Galaxies · Physics 2023-07-25 Sarah Appleby , Romeel Davé , Daniele Sorini , Christopher Lovell , Kevin Lo

We present in this article an analysis of some of the properties of the density field realized in numerical simulations for power-law initial power-spectra in the case of a critical density universe. We compare our numerical results in the…

Astrophysics · Physics 2009-10-31 P. Valageas , C. Lacey , R. Schaeffer