English
Related papers

Related papers: Variations in fundamental constants at the cosmic …

200 papers

We present an overview of recent developments in the detection of light bosonic dark matter, including axion, pseudoscalar axion-like and scalar dark matter, which form either a coherently oscillating classical field or topological defects…

Atomic Physics · Physics 2015-09-04 Y. V. Stadnik , V. V. Flambaum

We study the prospects for extracting detailed statistical properties of the neutral Hydrogen distribution during the era of reionization using the brightness temperature fluctuations from redshifted 21 cm line emission. Detection of this…

Astrophysics · Physics 2009-11-10 M. G. Santos , A. Cooray , L. Knox

We make use of Dirac LNH and results for a time varying fine structure constant in order to derive possible laws of variation for speed of light, the number of nucleons in the Universe, energy density and gravitational constant. By…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Marcelo S. Berman , Luis A. Trevisan

By employing Dirac LNH, and a further generalization by Berman (GLNH), we estimate how should vary the total number of nucleons, the energy density, Newton Gravitational constant, the cosmological constant, the magnetic permeability and…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Marcelo S. Berman , Luis A. Trevisan

Constrained measurements of fundamental physical constants using astronomical observational data represent a powerful method for investigating potential new physics. In particular, the dispersion measure (DM) of fast radio bursts (FRBs),…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-11 Shi-Yuan Wang , Jun-Qing Xia

It is predicted that sources emitting UV radiation in the Lyman band during the epoch of reionization (EoR) showed a series of discontinuities in their Ly-alpha flux radial profile as a consequence of the thickness of the Lyman line series…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 P. Vonlanthen , B. Semelin , S. Baek , Y. Revaz

Long wavelength spectral distortions in the Cosmic Microwave Background arising from the 21-cm transition in neutral Hydrogen are a key probe of Cosmic Dawn and the Epoch of Reionization. These features may reveal the nature of the first…

In recent years, a remarkably simple physical picture of the Lyman-alpha forest has emerged, which allows detailed predictions to be made and turns the forest into a powerful probe of cosmology. We point out ways in which such a picture can…

Astrophysics · Physics 2007-05-23 Lam Hui

In this work, a new generic parameterisation for $f(R)$ theories is presented. Our proposal for a new equation of state can reproduce an $f(R)$-like evolution that describes late and early time universe within 1-$\sigma$ C.L when we use a…

General Relativity and Quantum Cosmology · Physics 2020-11-20 N. M. Jiménez Cruz , Celia Escamilla-Rivera

The 21\,cm transition of neutral hydrogen is opening an observational window into the cosmic dawn of the universe---the epoch of first star formation. We use 28\,hr of data from the Owens Valley Radio Observatory Long Wavelength Array…

Spatial and temporal variations in the electron-to-proton mass ratio, mu, and in the fine-structure constant, alpha, are predicted in non-Standard models aimed to explain the nature of dark energy. Among them the so-called chameleon-like…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-20 S. A. Levshakov , I. I. Agafonova , P. Molaro , D. Reimers

The redshifts of all cosmologically distant sources are expected to experience a small, systematic drift as a function of time due to the evolution of the Universe's expansion rate. A measurement of this effect would represent a direct and…

A powerful test of fundamental physics consists on probing the variability of fundamental constants in Nature. Although they have been measured on Earth laboratories and in our Solar neighbourhood with extremely high precision, it is…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-27 Gabriel Rodrigues , Carlos Bengaly

We investigate the ability to constrain oscillatory features in the primordial power spectrum using current and future cosmic microwave background observations. In particular, we study the observability of an oscillation arising from…

Astrophysics · Physics 2011-05-12 Takemi Okamoto , Eugene A. Lim

Observations of the redshifted 21-cm line of atomic hydrogen have resulted in several upper limits on the 21-cm power spectrum and a tentative detection of the sky-averaged signal at $z\sim17$. Made with the EDGES Low-Band antenna, this…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-02 H. T. J. Bevins , A. Fialkov , E. de Lera Acedo , W. J. Handley , S. Singh , R. Subrahmanyan , R. Barkana

We study the role of fundamental constants in an updated recombination scenario. We focus on the time variation of the fine structure constant, and the electron mass in the early Universe, and put bounds on these quantities by using data…

Astrophysics · Physics 2008-10-31 Claudia G. Scóccola , Susana. J. Landau , Hector Vucetich

Current results from the Lyman alpha forest assume that the primordial power spectrum of density perturbations follows a simple power law form, with running. We present the first analysis of Lyman alpha data to study the effect of relaxing…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-16 Simeon Bird , Hiranya V. Peiris , Matteo Viel , Licia Verde

The astrophysics of cosmic dawn, when star formation commenced in the first collapsed objects, is predicted to be revealed as spectral and spatial signatures in the cosmic radio background at long wavelengths. The sky-averaged redshifted…

We present cosmological constraints on deviations of Newton's constant at large scales, analyzing latest cosmic microwave background (CMB) anisotropies and primordial abundances of light elements synthesized by big bang nucleosynthesis…

Astrophysics · Physics 2009-11-10 K. Umezu , K. Ichiki , M. Yahiro

The 21-cm signals from Cosmic Dawn and the Epoch of Reionization contain valuable information on cosmological structure formation dominated by dark matter. Measurements of the 21-cm power spectrum can thus probe certain dark matter…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-15 Shihang Liu , Yilin Liu , Bowen Peng , Mengzhou Xie , Zelong Liu , Bohua Li , Yi Mao