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The Genetic Algorithm is a heuristic that can be used to produce model independent solutions to an optimization problem, thus making it ideal for use in cosmology and more specifically in the analysis of type Ia supernovae data. In this…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-18 Savvas Nesseris

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

The standard concordance model of the Universe is based on the cosmological constant as the driver of accelerating expansion. This concordance model is being subjected to a growing range of inter-locking observations. In addition to using…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Sahba Yahya , Marina Seikel , Chris Clarkson , Roy Maartens , Mathew Smith

In this analysis we apply a model-independent framework to test the flat $\Lambda$CDM cosmology using simulated SNIa data from the upcoming Legacy Survey of Space and Time (LSST) and combined with simulated Dark Energy Spectroscopic…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-19 Benjamin L'Huillier , Ayan Mitra , Arman Shafieloo , Ryan E. Keeley , Hanwool Koo

A plethora of observational data obtained over the last couple of decades has allowed cosmology to enter into a precision era and has led to the foundation of the standard cosmological constant and cold dark matter paradigm, known as the…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-31 Rubén Arjona , Savvas Nesseris

Current and upcoming surveys will measure the cosmological parameters with an extremely high accuracy. The primary goal of these observations is to eliminate some of the currently viable cosmological models created to explain the late time…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Savvas Nesseris , Domenico Sapone

We investigate the null tests of spatial flatness and the flat $\Lambda$CDM model using the Baryon Acoustic Oscillation (BAO) data measured by the Dark Energy Spectroscopic Instrument (DESI), the cosmic chronometers (CCH) $H(z)$ data, and…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-08 Shengqing Gao , Qing Gao , Yungui Gong , Xuchen Lu

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

A natural extension of the standard cosmological model are models that include curvature as a free parameter. In this work we study in detail the observational constraints on the non-flat $\Lambda CDM$ model using the two main geometric…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-15 Velasquez-Toribio , A. M , Magnago , A. dos R

We test both the FLRW geometry and $\Lambda$CDM cosmology in a model independent way by reconstructing the Hubble function $H(z)$, the comoving distance $D(z)$ and the growth of structure $f\sigma_8(z)$ using the most recent data available.…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-18 Valerio Marra , Domenico Sapone

For years, the cosmological constant $\Lambda$ and cold dark matter (CDM) model ($\Lambda\text{CDM}$) has stood as a cornerstone in modern cosmology and serves as the predominant theoretical framework for current and forthcoming surveys.…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-24 Rubén Arjona , Savvas Nesseris , Isaac Tutusaus , Daniel Sobral Blanco , Camille Bonvin

Since there is no known symmetry in Nature that prevents a non-minimal coupling between the dark energy (DE) and cold dark matter (CDM) components, such a possibility constitutes an alternative to standard cosmology, with its theoretical…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-21 Rodrigo von Marttens , Valerio Marra , Luciano Casarini , J. E. Gonzalez , Jailson Alcaniz

We introduce a model-independent approach to the null test of the cosmic curvature which is geometrically related to the Hubble parameter $H(z)$ and luminosity distance $d_L(z)$. Combining the independent observations of $H(z)$ and…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-23 Rong-Gen Cai , Zong-Kuan Guo , Tao Yang

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

The DESI DR2 BAO data, in combination with CMB and different SNIa datasets, exclude the flat $\Lambda$CDM model at more than 2.5$\sigma$ when analyzed through the $w_0w_a$CDM parametrization for evolving dark energy. This simple…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-11 Bikash R. Dinda , Roy Maartens , Shun Saito , Chris Clarkson

The case for a flat Cold Dark Matter model with a positive cosmological constant $\Lambda$ has been recently strongly advocated by some theoreticians. In this paper we give the observers point of view to the light of the most recent…

Astrophysics · Physics 2007-05-23 B. Fort , Y. Mellier

The critical issue in cosmology today lies in determining if the cosmological constant is the underlying ingredient of dark energy. Our profound lack of understanding of the physics of dark energy places severe constrains on our ability to…

Astrophysics · Physics 2008-12-18 Caroline Zunckel , Chris Clarkson

The cosmic curvature $\Omega_{K,0}$, which determines the spatial geometry of the universe, is an important parameter in modern cosmology. Any deviation from $\Omega_{K,0}=0$ would have a profound impact on primordial inflation paradigm and…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-14 Peng-Ju Wu , Jing-Zhao Qi , Xin Zhang

In the present work, we apply consistency relation tests to several cosmological models, including the flat and non-flat $\Lambda$CDM models, as well as the flat XCDM model. The analysis uses a non-parametric Gaussian Processes method to…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-20 J. F. Jesus , A. A. Escobal , R. Valentim , S. H. Pereira

We study constraints that anticipated DEEP survey galaxy counts versus redshift data will place on cosmological model parameters in models with and without a constant or time-variable cosmological constant $\Lambda$. This data will result…

Astrophysics · Physics 2011-07-19 Silviu Podariu , Bharat Ratra
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