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Spatial averaging and time evolving are non-commutative operations in General Relativity, which questions the reliability of the FLRW model. The long standing issue of the importance of backreactions induced by cosmic inhomogeneities is…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-23 Sebastien Clesse , Arnaud Roisin , André Füzfa

Combining cosmological probes has consolidated the standard cosmological model with percent precision, but some tensions have recently emerged when certain parameters are estimated from the local or primordial Universe. The origin of this…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-16 Fabrizio Cogato , Michele Moresco , Lorenzo Amati , Andrea Cimatti

We study FRW cosmology for scalar tensor theory where two scalar functions nonminimally coupled to the geometry and matter Lagrangian. In a framework to study stability and attractor solutions of the model in the phase space, we…

General Relativity and Quantum Cosmology · Physics 2011-11-22 Hossein Farajollahi , Amin Salehi , Mohammad Nasiri

Accurate modeling of small-scale redshift-space clustering is crucial for full shape RSD analyses, where satellite galaxies contribute to 1-halo terms and Finger-of-God distortions. We investigate halo reconstruction based on the cylinder…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-14 Ryuichiro Hada , Teppei Okumura

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

Following the numerous evidence for large-scale cosmic isotropy violation with the advent of the `precision cosmology' era, we explore the possible advantages of extending the flat $\Lambda$CDM model to more general models in order to…

General Relativity and Quantum Cosmology · Physics 2026-02-05 Tanay Gupta , Anshul Verma , Sukanta Panda , Pavan K. Aluri

Recent distance ladder determinations of the Hubble constant $H_0$ disagree at about the $3.5\sigma$ level with the value determined from Planck measurements of the cosmic microwave background (CMB) assuming a $\Lambda$CDM cosmology. This…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-28 Pablo Lemos , Elizabeth Lee , George Efstathiou , Steven Gratton

We examine the properties of a recently proposed observationally viable alternative to homogeneous cosmology with smooth dark energy, the timescape cosmology. In the timescape model cosmic acceleration is realized as an apparent effect…

Cosmology and Nongalactic Astrophysics · Physics 2009-12-30 David L. Wiltshire

Do current observational data confirm the assumptions of the cosmological principle, or is there statistical evidence for deviations from spatial homogeneity on large scales? To address these questions, we developed a flexible framework…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-22 Matthias Redlich , Krzysztof Bolejko , Sven Meyer , Geraint F. Lewis , Matthias Bartelmann

We propose a new model-independent reconstruction method for the matter power spectrum based on its time dependence and a combination of observations from different redshifts. The method builds on a perturbative expansion in terms of the…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-12 Gen Ye , Jun-Qian Jiang , Alessandra Silvestri

There are two redshifts in cosmology: $z_{obs}$, the observed redshift computed via spectral lines, and the model redshift, $z$, defined by the effective FLRW scale factor. In general these do not coincide. We place observational…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-06 Bruce A. Bassett , Yabebal Fantaye , Renée Hložek , Cristiano Sabiu , Mat Smith

Accurate statistical inference in logistic regression models remains a critical challenge when the ratio between the number of parameters and sample size is not negligible. This is because approximations based on either classical asymptotic…

Methodology · Statistics 2022-08-19 Qian Zhao , Emmanuel J. Candes

Measurement of the universe expansion rate through the cosmic chronometers proves to be a novel approach to understanding cosmic history. Although it provides a direct determination of the Hubble parameters at different redshifts, it…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-12 Faeze Jalilvand , Ahmad Mehrabi

We use cosmological constraints from current data sets and a figure of merit (FoM) approach to probe any deviations from general relativity (GR) at cosmological scales. The FoM approach is used to study the constraining power of various…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-30 Jason Dossett , Jacob Moldenhauer , Mustapha Ishak

We infer the growth of large scale structure over the redshift range $0.4\lesssim z \lesssim 1$ from the cross-correlation of spectroscopically calibrated Luminous Red Galaxies (LRGs) selected from the Dark Energy Spectroscopic Instrument…

We examine the improvements in constraints on the linear growth factor G and its derivative f=d ln G / dln a that are available from the combination of a large-scale galaxy redshift survey with a weak gravitational lensing survey of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Gary M. Bernstein , Yan-Chuan Cai

We present a geometrical approach that provides a non-perturbative technique, allowing the standard FLRW observer to evaluate a measurable, scale-dependent distance functional between her idealized FLRW past light cone and the actual…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-09 Mauro Carfora , Francesca Familiari

We constrain the expansion history of the Universe and the cosmological matter density fraction in a model-independent way by exclusively making use of the relationship between background and perturbations under a minimal set of…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-16 Jaime Ruiz-Zapatero , Carlos García-García , David Alonso , Pedro G. Ferreira , Richard D. P. Grumitt

The observational evidence regarding the present cosmological aspects tells us about the presence of very little anisotropy in the universe on a large scale. Here, in this paper, we attempt to study locally rotationally symmetric (LRS)…

General Relativity and Quantum Cosmology · Physics 2022-11-02 N. S. Kavya , V. Venkatesha , Sanjay Mandal , P. K. Sahoo

Upcoming surveys such as \LSST{} and \Euclid{} will significantly improve the power of weak lensing as a cosmological probe. To maximise the information that can be extracted from these surveys, it is important to explore novel statistics…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-18 Christopher T. Davies , Marius Cautun , Benjamin Giblin , Baojiu Li , Joachim Harnois-Déraps , Yan-Chuan Cai