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The main aim of this paper is to perform a model comparison for some reconstructions of the key properties that describe the dark energy of the Universe i.e. energy density and the equation of state (EoS). We carry out this process by using…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-28 Luis A. Escamilla , J. Alberto Vazquez

Within the Machian model of the universe the dark energy is identified with the Machian energy of collective gravitational interactions of all particles inside the horizon. It is shown that the fine structure constant can be expressed in…

General Relativity and Quantum Cosmology · Physics 2010-09-28 Merab Gogberashvili , Igor Kanatchikov

Since galaxy distribution reconstruction effectively reduces non-Gaussian terms in the power spectrum covariance matrix, it has attracted interest not only for Baryon Acoustic Oscillation (BAO) signals but also for various cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-16 Naonori Sugiyama

High energy astrophysics has made good use of combined high energy (X-ray, gamma-ray) and radio observations to uncover connections between outbursts, accretion, particle acceleration and kinetic feedback to the local ambient medium. In the…

Astrophysics · Physics 2008-10-07 Rob Fender

There is now strong evidence that the current energy density of the Universe is dominated by dark energy with an equation of state w<-1/3, which is causing accelerated expansion. The build-up of structure within such Universes is subject to…

Astrophysics · Physics 2008-11-26 Will J. Percival

We provide an overview of 21cm tomography of the Cosmic Dawn and Epoch of Reionization as possible with SKA-Low. We show why tomography is essential for studying CD/EoR and present the scales which can be imaged at different frequencies for…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-14 Garrelt Mellema , León Koopmans , Hemant Shukla , Kanan K. Datta , Andrei Mesinger , Suman Majumdar

New observational constraints on the cosmic matter density $\Omega_m$ and an effectively redshift-independent equation of state parameter $w_x$ of the dark energy are obtained while simultaneously testing the strong and null energy…

The recent low value of Planck (2016) integrated optical depth to Thomson scattering suggests that the reionization occurred fairly suddenly, disfavoring extended reionization scenarios. This will have a significant impact on the 21cm power…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-27 Sultan Hassan , Romeel Dave , Kristian Finlator , Mario G. Santos

The compact configuration of Phase II of the Murchison Widefield Array (MWA) consists of both a redundant subarray and pseudo-random baselines, offering unique opportunities to perform sky-model and redundant interferometric calibration.…

Over the next decade, cosmological measurements of the large-scale structure of the Universe will be sensitive to the combined effects of dynamical dark energy and massive neutrinos. The matter power spectrum is a key repository of this…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-21 Amol Upadhye , Rahul Biswas , Adrian Pope , Katrin Heitmann , Salman Habib , Hal Finkel , Nicholas Frontiere

We review the current status of cosmological parameters, dark energy and large-scale structure, from a theoretical and observational perspective. We first present the basic cosmological parameters and discuss how they are measured with…

Astrophysics · Physics 2007-05-23 S. E. Deustua , R. Caldwell , P. Garnavich , L. Hui , A. Refregier

Feedback processes from baryons are expected to strongly affect weak-lensing observables of current and future cosmological surveys. In this paper we present a new parametrisation of halo profiles based on gas, stellar, and dark matter…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-02 Aurel Schneider , Romain Teyssier , Joachim Stadel , Nora Elisa Chisari , Amandine M. C. Le Brun , Adam Amara , Alexandre Refregier

The expansion of the universe appears to be accelerating, and the mysterious anti-gravity agent of this acceleration has been called ``dark energy''. To measure the dynamics of dark energy, Baryon Acoustic Oscillations (BAO) can be used.…

Astrophysics · Physics 2008-11-26 Tzu-Ching Chang , Ue-Li Pen , Jeffrey B. Peterson , Patrick McDonald

The book elucidates the current state of the dark energy problem and presents the results of the authors, who work in this area. It describes the observational evidence for the existence of dark energy, the methods and results of…

Cosmology and Nongalactic Astrophysics · Physics 2015-02-17 B. Novosyadlyj , V. Pelykh , Yu. Shtanov , A. Zhuk

This lecture briefly reviews the major recent advances in radio astronomy made possible by ultra-deep surveys, reaching microJansky flux density levels. A giant step forward in many fields, including the study of the evolution of the cosmic…

Astrophysics of Galaxies · Physics 2018-03-20 Gianfranco De Zotti , Matteo Bonato , Zhen-Yi Cai

We use the latest multi-redshift ($z=6.5-8.7$) upper limits on the 21-cm signal from the Murchison Widefield Array (MWA) to explore astrophysical models which are inconsistent with the data. These upper limits are achieved using 298 h of…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-25 Bradley Greig , Cathryn M. Trott , Nichole Barry , Simon J. Mutch , Bart Pindor , Rachel L. Webster , J. Stuart B. Wyithe

Starting around 2013, data from the Large Synoptic Survey Telescope (LSST) will be analyzed for a wide range of phenomena. By separately tracing the development of mass structure and rate of expansion of the universe, these data will…

Astrophysics · Physics 2019-08-14 J. Anthony Tyson

The Square Kilometre Array (SKA) is a planned radio interferometer of unprecedented scale that will revolutionize low-frequency radio astronomy when completed. In particular, one of its core science drivers is the systematic mapping of the…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-11 Nichole Barry , Gianni Bernardi , Bradley Greig , Nicholas Kern , Florent Mertens

We investigated a possible interaction between cold dark matter and dark energy, corresponding to a well-known interacting dark energy model discussed in the literature within the context of resolving the Hubble tension. We put constraints…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-21 David Benisty , Supriya Pan , Denitsa Staicova , Eleonora Di Valentino , Rafael C. Nunes