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Cosmic shear estimation is an essential scientific goal for large galaxy surveys. It refers to the coherent distortion of distant galaxy images due to weak gravitational lensing along the line of sight. It can be used as a tracer of the…

Machine Learning · Computer Science 2021-04-21 Claire Theobald , Bastien Arcelin , Frédéric Pennerath , Brieuc Conan-Guez , Miguel Couceiro , Amedeo Napoli

This work determines the degree to which a standard Lambda-CDM analysis based on type Ia supernovae can identify deviations from a cosmological constant in the form of a redshift-dependent dark energy equation of state w(z). We introduce…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-10 Ben Moews , Rafael S. de Souza , Emille E. O. Ishida , Alex I. Malz , Caroline Heneka , Ricardo Vilalta , Joe Zuntz

It has been argued recently by Copi etal (2009) that the lack of large angular correlations of the CMB temperature field provides strong evidence against the standard, statistically isotropic, inflationary LambdaCDM cosmology. We compare…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 George Efstathiou , Yin-Zhe Ma , Duncan Hanson

We present a new method for calculating CMB anisotropies in a non-flat Friedmann universe, relying on a very stable algorithm for the calculation of hyperspherical Bessel functions, that can be pushed to arbitrary precision levels. We also…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Julien Lesgourgues , Thomas Tram

Measuring the quasar distance through joint analysis of spectroastrometry (SA) and reverberation mapping (RM) observations is a new method for driving the development of cosmology. In this paper, we carry out detailed simulation and…

High Energy Astrophysical Phenomena · Physics 2022-03-14 Ying-Ke Huang , Yue-Dong Fang , Kai-Xing Lu , Zhi-Xiang Zhang , Ji-Lin Liu , Sha-sha Li , Bao-Rui Luo , Qin Lin , Zhuo-Xi Huo

A major goal of cosmology is to obtain sensitive, high resolution maps of the Cosmic Microwave Background (CMB) anisotropy. Such maps, as would be produced by the recently proposed Microwave Anisotropy Probe (MAP), will contain a wealth of…

Astrophysics · Physics 2009-10-28 Edward L. Wright , Gary Hinshaw , Charles L. Bennett

We use cosmography to present constraints on the kinematics of the Universe, without postulating any underlying theoretical model. To this end, we use a Monte Carlo Markov Chain analysis to perform comparisons to the supernova Ia Union 2…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Alejandro Aviles , Christine Gruber , Orlando Luongo , Hernando Quevedo

Aims: In view of the substantial uncertainties regarding the possible dynamics of the dark energy, we aim at constraining the expansion rate of the universe without reference to a specific Friedmann model and its parameters. Methods: We…

Astrophysics · Physics 2008-04-08 Claudia Mignone , Matthias Bartelmann

If the Universe is endowed with cosmic anisotropy, it will have a preferred direction of expansion. Reconstructing the expansion history by Gaussian Process (GP) can be used to probe the cosmic anisotropy model-independently. In this paper,…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-25 Zong-Fan Yang , Da-Wei Yao , Ke Wang

Various astronomical observations have been consistently making a strong case for the existence of a component of dark energy with negative pressure in the universe. It is now necessary to take the dark energy component(s) into account in…

Astrophysics · Physics 2014-10-13 Zong-Hong Zhu

Two types of distance measurement are important in cosmological observations, the angular diameter distance $d_A$ and the luminosity distance $d_L$. In the present work, we carried out an assessment of the theoretical relation between these…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-02 Purba Mukherjee , Ankan Mukherjee

In this study, by revisiting the quantum interpretation of the cosmological constant, we introduce its formal representation within standard General Relativity. Examining its behavior in a Friedmann-Robertson-Walker spacetime reveals a…

General Relativity and Quantum Cosmology · Physics 2026-02-26 H. R. Fazlollahi

A numerical method is developed to solve the time-dependent Dirac equation in cylindrical coordinates for 3-D axisymmetric systems. The time evolution is treated by a splitting scheme in coordinate space using alternate direction iteration,…

Computational Physics · Physics 2015-04-03 François Fillion-Gourdeau , Emmanuel Lorin , André D. Bandrauk

A class of cosmological solutions of higher dimensional Einstein field equations with the energy-momentum tensor of a homogeneous, isotropic fluid as the source are considered with an anisotropic metric that includes the direct sum of a…

General Relativity and Quantum Cosmology · Physics 2013-10-24 Ozgur Akarsu , Tekin Dereli

There are two basic ways to measure physical distances in cosmology: One based on standard candles and one based on standard rulers. Comparing current data for each method allows us to rule out axion-photon mixing and dust-extinction as the…

Astrophysics · Physics 2007-05-23 Martin Kunz , Bruce A. Bassett

Outside galaxy clusters the competition between the inwards gravitational attraction and the outwards expansion of the Universe leads to a special radius of velocity cancellation, which is called the turn-around radius. Measurements of the…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-02 Steen H. Hansen , Farbod Hassani , Lucas Lombriser , Martin Kunz

We present a novel and efficient implementation of coupled-cluster with singles and doubles (CCSD) analytic gradients that combines the Cholesky decomposition (CD) of electron-repulsion integrals with the exploitation of Abelian point-group…

Chemical Physics · Physics 2025-12-29 Luca Melega , Tommaso Nottoli , Jürgen Gauss , Filippo Lipparini

In this work we present 21cmFirstCLASS, a modified version of 21cmFAST, the most popular code in the literature for computing the anisotropies of the 21-cm signal. Our code uses the public cosmic microwave background (CMB) Boltzmann code…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-29 Jordan Flitter , Ely D. Kovetz

We introduce a Markov Chain Monte Carlo simulation and data analysis package that extends the CMBEASY software. We have taken special care in implementing an adaptive step algorithm for the Markov Chain Monte Carlo in order to improve…

Astrophysics · Physics 2007-05-23 Michael Doran , Christian M. Mueller

Assessing the consistency of parameter constraints derived from different cosmological probes is an important way to test the validity of the underlying cosmological model. In an earlier work [Nicola et al., 2017], we computed constraints…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-01 Andrina Nicola , Adam Amara , Alexandre Refregier
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