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Recent galaxy redshift surveys have brought in a large amount of accurate cosmological data out to redshift 0.3, and future surveys are expected to achieve a high degree of completeness out to a redshift exceeding 1. Consequently, a…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Teresa Hui-Ching Lu , Charles Hellaby

We present a new algorithm that can reconstruct the full distributions of metric components within the class of spherically symmetric dust universes that may include a cosmological constant. The algorithm is capable of confronting this…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-07 Hertzog L. Bester , Julien Larena , Nigel T. Bishop

The current accelerated expansion of the Universe remains ones of the most intriguing topics in modern cosmology, driving the search for innovative statistical techniques. Recent advancements in machine learning have significantly enhanced…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-03 José de Jesús Velázquez , Luis A. Escamilla , Purba Mukherjee , J. Alberto Vázquez

We give an outline of an algorithm designed to reconstruct the background cosmological metric within the class of spherically symmetric dust universes that may include a cosmological constant. Luminosity and age data are used to derive…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-29 Hertzog L. Bester , Julien Larena , Nigel T. Bishop

We present methods to rigorously extract parameter combinations that are constrained by data from posterior distributions. The standard approach uses linear methods that apply to Gaussian distributions. We show the limitations of the linear…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-06 Tara Dacunha , Marco Raveri , Minsu Park , Cyrille Doux , Bhuvnesh Jain

We propose a non-parametric method of smoothing supernova data over redshift using a Gaussian kernel in order to reconstruct important cosmological quantities including H(z) and w(z) in a model independent manner. This method is shown to be…

Astrophysics · Physics 2009-11-24 Arman Shafieloo , Ujjaini Alam , Varun Sahni , Alexei A. Starobinsky

The prospect of nonparametric reconstructions of cosmological parameters from observational data sets has been a popular topic in the literature for a number of years. This has mainly taken the form of a technique based on Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-24 Konstantinos Dialektopoulos , Jackson Levi Said , Jurgen Mifsud , Joseph Sultana , Kristian Zarb Adami

We discuss how the ideal formalism of Computational Mechanics can be adapted to apply to a non-infinite series of corrupted and correlated data, that is typical of most observed natural time series. Specifically, a simple filter that…

Statistical Mechanics · Physics 2007-05-23 Richard W. Clarke , Mervyn P. Freeman , Nicholas W. Watkins

We present the time drift of the cosmological redshift in a general spherically symmetric spacetime. We demonstrate that its observation would allow us to test the Copernican principle and so determine if our universe is radially…

Astrophysics · Physics 2009-06-23 Jean-Philippe Uzan , Chris Clarkson , George F. R. Ellis

The analysis of modern cosmological data is becoming an increasingly important task as the amount of data multiplies. An important goal is to extract geometric information, i.e. the metric of the cosmos, from observational data. The…

General Relativity and Quantum Cosmology · Physics 2009-02-20 Charles Hellaby , Alnadhief H. A. Alfedeel

We derive a method to reconstruct Gaussian signals from linear measurements with Gaussian noise. This new algorithm is intended for applications in astrophysics and other sciences. The starting point of our considerations is the principle…

Instrumentation and Methods for Astrophysics · Physics 2011-10-18 Niels Oppermann , Georg Robbers , Torsten A. Ensslin

We investigate uncertainties in the estimation of the Hubble constant ($H_0$) arising from Gaussian Process (GP) reconstruction, demonstrating that the choice of kernel introduces systematic variations comparable to those arising from…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-07 Ruchika , Purba Mukherjee , Arianna Favale

We present an algorithm for the construction of conformal coordinates in the interior of a spherically symmetric, collapsing matter cloud in general relativity. This algorithm is based on the numerical integration of the radial null…

General Relativity and Quantum Cosmology · Physics 2014-06-17 Néstor Ortiz , Olivier Sarbach

This survey is devoted to recent developments in the statistical analysis of spherical data, with a view to applications in Cosmology. We will start from a brief discussion of Cosmological questions and motivations, arguing that most…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-28 Javier Carrón Duque , Domenico Marinucci

We use astrophysical data to shed light on fundamental physics by constraining parametrized theoretical cosmological and gravitational models. Gravitational parameters are those constants that parametrize possible departures from Einstein's…

Astrophysics · Physics 2008-08-18 Yi Mao

The assumption of a flat Universe that follows the cosmological principle, i.e., that the universe is statistically homogeneous and isotropic at large scales, comprises one of the core foundations of the standard cosmological model --…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-24 Mariana L. S. Dias , Antônio F. B. da Cunha , Carlos A. P. Bengaly , Rodrigo S. Gonçalves , Jonathan Morais

Gaussian processes provide a method for extracting cosmological information from observations without assuming a cosmological model. We carry out cosmography -- mapping the time evolution of the cosmic expansion -- in a model-independent…

Cosmology and Nongalactic Astrophysics · Physics 2012-07-11 Arman Shafieloo , Alex G. Kim , Eric V. Linder

The discrepancy between the observed value of the cosmological constant (CC) and its expected value from quantum field theoretical considerations motivates the search for a theory in which the CC is decoupled from the vacuum energy. In this…

General Relativity and Quantum Cosmology · Physics 2025-01-14 Justin C. Feng , Pisin Chen

Future gravitational wave (GW) standard siren catalogues will probe the late-time expansion history of the Universe across redshift ranges largely inaccessible to traditional electromagnetic observations. To determine how effectively this…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-27 Gourab Nandi , Anish Ghoshal , David F. Mota

In quantum gravity, we envision renormalization as the key tool for bridging the gap between microscopic models and observable scales. For spin foam quantum gravity, which is defined on a discretisation akin to lattice gauge theories, the…

General Relativity and Quantum Cosmology · Physics 2020-07-06 Sebastian Steinhaus
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