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We present a coherent, re-usable python framework which further builds on the cosmological emulator code CosmoPower. In the current era of high-precision cosmology, we require high-accuracy calculations of cosmological observables with…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-14 H. T. Jense , I. Harrison , E. Calabrese , A. Spurio Mancini , B. Bolliet , J. Dunkley , J. C. Hill

The current standard model of cosmology, the LambdaCDM model, is based on the homogeneous FLRW solutions of the Einstein equations to which some perturbations are added to account for the CMB features and structure formation at large…

Cosmology and Nongalactic Astrophysics · Physics 2012-03-14 Marie-Noëlle Célérier

Advances in our understanding of the origin, evolution and structure of the universe have long been driven by cosmological perturbation theory, model building and effective field theory. In this review, we introduce numerical relativity as…

General Relativity and Quantum Cosmology · Physics 2022-03-08 Anna Ijjas

Starting from the inhomogeneous shear--free Nariai metric we show, by solving the Einstein--Klein--Gordon field equations, how a self--interacting scalar field plus a material fluid, a variable cosmological term and a heat flux can drive…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Luis P. Chimento , Alejandro S. Jakubi , Diego Pavon

An alternative to the postulate of dark energy required to explain the accelerated expansion of the universe is to adopt an inhomogeneous cosmological model to explain the supernovae data without dark energy. We adopt a void cosmology…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-02 J. W. Moffat

We present cosmo_learn, an open-source python-based software package designed to simulate cosmological data and perform data-driven inference using a range of modern statistical and machine learning techniques. Motivated by the growing…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-29 Reginald Christian Bernardo , Daniela Grandón , Jackson Levi Said , Víctor H. Cárdenas , Gene Carlo Belinario , Reinabelle Reyes

We explore strategies to extract cosmological constraints from a joint analysis of cosmic shear, galaxy-galaxy lensing, galaxy clustering, cluster number counts and cluster weak lensing. We utilize the CosmoLike software to simulate results…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-26 Elisabeth Krause , Tim Eifler

Cosmography is an ideal tool to investigate the cosmic expansion history of the Universe in a model-independent way. The equations of motion in modified theories of gravity are usually very complicated; cosmography may select practical…

General Relativity and Quantum Cosmology · Physics 2021-01-04 Sanjay Mandal , Deng Wang , P. K. Sahoo

We give a formulation of quantum cosmology with a pressureless dust and arbitrary additional matter fields. The system has the property that its Hamiltonian constraint is linear in the dust momentum. This feature provides a natural time…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Viqar Husain , Tomasz Pawlowski

Relativistic numerical cosmology is most often based either on the exact solutions of the Einstein equations, or perturbation theory, or weak-field limit, or the BSSN formalism. The Silent Universe provides an alternative approach to…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-08 Krzysztof Bolejko

It is the common consensus that the expansion of a universe always slows down if the gravity provided by the energy sources therein is attractive and accordingly one needs to invoke dark energy as a source of anti-gravity for understanding…

Astrophysics · Physics 2008-11-26 Chia-Hsun Chuang , Je-An Gu , W-Y. P. Hwang

We study the dynamical behaviour of gauge-invariant linear perturbations in spherically symmetric dust cosmologies including a cosmological constant. In contrast to spatially homogeneous FLRW models, the reduced degree of spatial symmetry…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-27 Sven Meyer , Matthias Bartelmann

We discuss the Buchert equations, which describe the average expansion of an inhomogeneous dust universe. In the limit of small perturbations, they reduce to the Friedmann-Robertson-Walker equations. However, when the universe is very…

Astrophysics · Physics 2008-11-26 Syksy Rasanen

In standard perturbation approaches and N-body simulations, inhomogeneities are described to evolve on a predefined background cosmology, commonly taken as the homogeneous-isotropic solutions of Einstein's field equations…

General Relativity and Quantum Cosmology · Physics 2012-05-11 Xavier Roy , Thomas Buchert

Isotropic inhomogeneous dust universes are analysed via observational coordinates based on the past light cones of the observer's galactic worldline. The field equations are reduced to a single first--order {\sc ode} in observational…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Roy Maartens , Neil Humphreys , David Matravers , Bill Stoeger

We study the evolution of cosmological perturbations, using a hybrid approximation scheme which upgrades the weak-field limit of Einstein's field equations to account for post-Newtonian scalar and vector metric perturbations and for…

Astrophysics · Physics 2007-05-23 Carmelita Carbone , Sabino Matarrese

Large scale structure of the Universe becomes a leading source of precision cosmological information. We present two particular tools that can be used in cosmological analyses of the redshift space galaxy clustering data: a new open-source…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-15 A. Chudaykin

We reexamine cosmological applications of the holographic energy density in the framework of sourced Friedmann equations. This framework is suitable because it can accommodate a macroscopic interaction between holographic and ordinary…

High Energy Physics - Theory · Physics 2010-04-05 Yun Soo Myung

We present new numerical tools to analyse cosmic void catalogues, implemented inside the CosmoBolognaLib, a large set of Open Source C++/Python numerical libraries. The CosmoBolognaLib provides a common numerical environment for…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-22 Tommaso Ronconi , Federico Marulli

We study the dynamics of small inhomogeneities in an expanding universe collapsing to form bound structures using full solutions of the Einstein-Vlasov (N-body) equations. We compare these to standard Newtonian N-body solutions using…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-28 William E. East , Radosław Wojtak , Frans Pretorius