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The increase of discrepancy in the standard procedure to choose the arbitrary functional form of the Lagrangian $f(Q)$ motivates us to solve this issue in modified theories of gravity. In this regard, we investigate the Gaussian process…

General Relativity and Quantum Cosmology · Physics 2024-09-06 Gaurav N. Gadbail , Sanjay Mandal , P. K. Sahoo

We develop a new tool to generate statistically precise dark matter maps from the cosmic magnification of galaxies with distance estimates. We show how to overcome the intrinsic clustering problem using the slope of the luminosity function,…

Astrophysics · Physics 2008-11-26 Pengjie Zhang , Ue-Li Pen

Cosmological backreaction suggests a link between structure formation and the expansion history of the Universe. In order to quantitatively examine this connection, we dynamically investigate a volume partition of the Universe into over--…

Cosmology and Nongalactic Astrophysics · Physics 2010-08-18 Alexander Wiegand , Thomas Buchert

Gaussian processes (GPs) have been extensively utilized as nonparametric models for component separation in 21 cm data analyses. This exploits the distinct spectral behavior of the cosmological and foreground signals, which are modeled…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-13 Kangning Diao , Richard D. P. Grumitt , Yi Mao

The recently constructed Hubble diagram using a combined sample of SNLS and SDSS-II Type Ia SNe, and an application of the Alcock-Paczynski (AP) test using model-independent Baryon Acoustic Oscillation data, have suggested that the…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-25 Fulvio Melia , Thomas M. McClintock

We construct a three-dimensional, fully relativistic numerical model of a universe filled with an inhomogeneous pressureless fluid, starting from initial data that represent a perturbation of the Einstein-de Sitter model. We then measure…

General Relativity and Quantum Cosmology · Physics 2016-10-11 Eloisa Bentivegna , Marco Bruni

Direct observations of the Hubble rate, from cosmic chronometers and the radial baryon acoustic oscillation scale, can out-perform supernovae observations in understanding the expansion history, because supernovae observations need to be…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-26 Marina Seikel , Sahba Yahya , Roy Maartens , Chris Clarkson

The cosmological constant $\Lambda$ and cold dark matter (CDM) model ($\Lambda\text{CDM}$) is one of the pillars of modern cosmology and is widely used as the de facto theoretical model by current and forthcoming surveys. As the nature of…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-08 Rubén Arjona , Alessandro Melchiorri , Savvas Nesseris

We apply a mass reconstruction technique to simulated large-scale structure gravitational distortion maps, from 2.5' to 10 degree scales, for different cosmological scenarii. The projected mass is reconstructed using a non-parametric least…

Astrophysics · Physics 2007-05-23 L. Van Waerbeke , F. Bernardeau , Y. Mellier

We nonparametrically reconstruct the late-time expansion history in light of the latest Baryon Acoustic Oscillation (BAO) measurements from DESI combined with various Type Ia Supernovae (SNeIa) catalogs, using interpolation through…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-12 Jun-Qian Jiang , Davide Pedrotti , Simony Santos da Costa , Sunny Vagnozzi

We present charm (cosmic history agnostic reconstruction method), a novel inference algorithm that reconstructs the cosmic expansion history as encoded in the Hubble parameter $H(z)$ from SNe Ia data. The novelty of the approach lies in the…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-08 Natàlia Porqueres , Torsten A. Enßlin , Maksim Greiner , Vanessa Böhm , Sebastian Dorn , Pilar Ruiz-Lapuente , Alberto Manrique

Combining measurements on the expansion history of the Universe and on the growth rate of cosmic structures is key to discriminate between alternative cosmological frameworks and to test gravity. Recently, Linder (2017) proposed a new…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-16 Michele Moresco , Federico Marulli

In light of the statistical performance of cosmological observations, in this work we present an improvement on the Gaussian reconstruction of the Hubble parameter data $H(z)$ from Cosmic Chronometers, Supernovae Type Ia and Clustering…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-28 Mauricio Reyes , Celia Escamilla-Rivera

The accelerated cosmic expansion could be due to dark energy within general relativity (GR), or modified gravity. It is of interest to differentiate between them, by using both the expansion history and the growth history. In the…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-07 Zhao-Yu Yin , Hao Wei

We address the generation of initial conditions (ICs) for GRAMSES, a code for nonlinear general relativistic (GR) $N$-body cosmological simulations recently introduced in Ref. [1]. GRAMSES adopts a constant mean curvature slicing with a…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-06 Cristian Barrera-Hinojosa , Baojiu Li

The $H_0$-tension problem poses a confrontation of dark energy driving late-time cosmological expansion measured by the Hubble parameter $H(z)$ over an extended range of redshifts $z$. Distinct values $H_0\simeq 73$ km\,s$^{-1}$Mpc$^{-1}$…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-15 Maurice H. P. M. van Putten

A Bayesian statistical analysis using redshift space distortions data is performed to test a model of Symmetric Teleparallel Gravity where gravity is non-metrical. The cosmological background mimics a $\Lambda$CDM evolution but differences…

General Relativity and Quantum Cosmology · Physics 2020-06-15 Bruno J. Barros , Tiago Barreiro , Tomi Koivisto , Nelson J. Nunes

In this work we use cosmography to alleviate the degeneracy among cosmological models, proposing a way to parameterize matter and dark energy in terms of cosmokinematics quantities. The recipe of using cosmography allows to expand…

General Relativity and Quantum Cosmology · Physics 2015-12-23 Orlando Luongo , Giovanni Battista Pisani , Antonio Troisi

We present new determinations of the cosmic expansion history from red-envelope galaxies. We have obtained for this purpose high-quality spectra with the Keck-LRIS spectrograph of red-envelope galaxies in 24 galaxy clusters in the redshift…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Daniel Stern , Raul Jimenez , Licia Verde , Marc Kamionkowski , S. Adam Stanford

Despite the significant accomplishments of general relativity, numerous unresolved issues persist in our understanding of the cosmos. One of the most perplexing challenges is the ongoing accelerated expansion of the Universe, which…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-22 M. Koussour , N. Myrzakulov , Alnadhief H. A. Alfedeel , Amare Abebe
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