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There is growing interest in using 3-dimensional neutral hydrogen mapping with the redshifted 21 cm line as a cosmological probe, as it has been argued to have a greater long-term potential than the cosmic microwave background. However, its…

Astrophysics · Physics 2008-11-26 Yi Mao , Max Tegmark , Matthew McQuinn , Matias Zaldarriaga , Oliver Zahn

Current and upcoming cosmological observations allow us to probe structures on smaller and smaller scales, entering highly nonlinear regimes. In order to obtain theoretical predictions in these regimes, large cosmological simulations have…

Dark matter cannot be observed directly, but its weak gravitational lensing slightly distorts the apparent shapes of background galaxies, making weak lensing one of the most promising probes of cosmology. Several observational studies have…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-18 Dezső Ribli , Bálint Ármin Pataki , István Csabai

The Hubble diagram is one of the cornerstones of observational cosmology. It is usually analysed assuming that, on average, the underlying relation between magnitude and redshift matches the prediction of a…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-05 Pierre Fleury , Chris Clarkson , Roy Maartens

The large amount of cosmological data already available (and in the near future) makes necessary the development of efficient numerical codes. Many software products have been implemented to perform cosmological analyses considering one or…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-16 Sandro Dias Pinto Vitenti , Mariana Penna-Lima

The properties of universes are explored that are entirely in the interior of black holes in another universe, a `mother universe'. It is argued that these models offer a paradigm that may shed a new light on old cosmological problems. The…

General Relativity and Quantum Cosmology · Physics 2022-10-17 Herwig Dejonghe

One of the main goals of physical cosmology is to reconstruct the expansion history of the universe and finding the actual model of dark energy. In this article I review the difficulties of understanding dark energy and discuss about two…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-30 Arman Shafieloo

We present a unified approach to the problems of reconstruction of large-scale structure distribution in the universe and determination of the underlying power spectrum. These have often been treated as two separate problems and different…

Astrophysics · Physics 2009-10-30 Uros Seljak

In this work, we reconstruct the H(z) based on observational Hubble data with Artificial Neural Network, then estimate the cosmological parameters and the Hubble constant. The training data we used are covariance matrix and mock H(z), which…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-23 Jie-feng Chen , Tong-Jie Zhang , Peng He , Tingting Zhang , Jie Zhang

We examine the Pantheon supernovae distance data compilation in a model independent analysis to test the validity of cosmic history reconstructions beyond the concordance $\Lambda$CDM cosmology. Strong deviations are allowed by the data at…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-19 Benjamin L'Huillier , Arman Shafieloo , Eric V. Linder , Alex G. Kim

We present a joint likelihood analysis of the halo power spectrum and bispectrum in real space. We take advantage of a large set of numerical simulations and of an even larger set of halo mock catalogs to provide a robust estimate of the…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-23 Andrea Oddo , Federico Rizzo , Emiliano Sefusatti , Cristiano Porciani , Pierluigi Monaco

In this thesis, the implications of a new cosmological model are studied, which has features similar to that of decaying vacuum cosmologies. Decaying vacuum (or cosmological constant \Lambda) models are the results of attempts to resolve…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Moncy V. John

Currently, a method has been developed for the cosmological inflation model with a single scalar field to calculate cosmological parameters such as the power spectrum of scalar and tensor perturbations, their spectral indices, and the…

General Relativity and Quantum Cosmology · Physics 2025-01-06 Katerina Bolshakova , Sergey Chervon

The supernovae Hubble diagram traces the expansion history of the universe, including the influence of dark energy. Its use to probe the cosmological model can fruitfully be guided by heuristic study of the features of the model curves. By…

Astrophysics · Physics 2007-05-23 Eric V. Linder

How much cosmological information can we reliably extract from existing and upcoming large-scale structure observations? Many summary statistics fall short in describing the non-Gaussian nature of the late-time Universe in comparison to…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-15 Kai Lehman , Sven Krippendorf , Jochen Weller , Klaus Dolag

The data of type Ia supernovae observed by the High-z SN Search Team and Supernova Cosmology Project are analyzed in inhomogeneous cosmological models with a local void on scales of about 200 Mpc, to derive the best-fit values of model…

Astrophysics · Physics 2009-11-06 Kenji Tomita

We present a cosmographic study designed to test the simplest type of accelerating cosmology: a flat universe with matter and a cosmological constant ($\Lambda$). Hubble series expansions are fit to the SCP Union2.1 supernova data set to…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-17 Brett Bochner , Damon Pappas , Menglu Dong

We propose here a \emph{novel} method which singles out the \emph{a priori} unavoidable dependence on the underlying cosmological model when extracting parameter constraints, providing robust limits which only depend on the considered…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-30 S. Gariazzo , O. Mena

Exclusion zones in the cross-correlations between critical points (peak-void, peak-wall, filament-wall, filament-void) of the density field define quasi-standard rulers that can be used to constrain dark matter and dark energy cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-19 Junsup Shim , Christophe Pichon , Dmitri Pogosyan , Stephen Appleby , Corentin Cadiou , Juhan Kim , Katarina Kraljic , Changbom Park

The normal parameters are a non--linear transformation of the cosmological parameters whose likelihood function is very well--approximated by a normal distribution. This transformation serves as an extreme form of data compression allowing…

Astrophysics · Physics 2009-11-07 Mike Chu , Manoj Kaplinghat , Lloyd Knox