Related papers: Measuring the fine structure constant on white dwa…
We study the change of the effective fine structure constant in the cosmological models of a scalar field with a non-vanishing coupling to the electromagnetic field. Combining cosmological data and terrestrial observations we place…
Temporal and spatial variation of fine-structure constant $\alpha\equiv e^2/\hbar c$ in cosmology has been reported in analysis of combination Keck and VLT data. This paper studies this variation based on consideration of basic spacetime…
Absorption line systems detected in quasar spectra can be used to compare the value of the fine-structure constant, {\alpha}, measured today on Earth with its value in distant galaxies. In recent years, some evidence has emerged of small…
Quasar spectra reveal a rich array of important astrophysical information about galaxies which intersect the quasar line of sight. They also enable tests of the variability of fundamental constants over cosmological time and…
An undersampled point spread function may interact with the microstructure of a solid-state detector such that the total flux detected can depend sensitively on where the PSF center falls within a pixel. Such intra-pixel sensitivity…
We explore a possible time variation of the fine structure constant ($\alpha \equiv e^2/\hbar c$) using the Sunyaev-Zel'dovich effect measurements of galaxy clusters along with their X-ray observations. Specifically, the ratio of the…
Strong gravitational lensing by galaxy clusters is a fundamental tool to study dark matter and constrain the geometry of the Universe. Recently, the Hubble Space Telescope Frontier Fields programme has allowed a significant improvement of…
QSO absorption spectra provide an extremely useful probe of possible cosmological variation in various physical constants. Comparison of H I 21cm absorption with corresponding molecular (rotational) absorption spectra allows us to constrain…
In the second paper of this series we extend our Bayesian reanalysis of the evidence for a cosmic variation of the fine structure constant to the semi-parametric modelling regime. By adopting a mixture of Dirichlet processes prior for the…
Light scalar fields very naturally appear in modern cosmological models, affecting such parameters of Standard Model as electromagnetic fine structure constant $\alpha$, dimensionless ratios of electron or quark mass to the QCD scale,…
The measurement of the Hubble constant from gravitational wave (GW) sources is one of the independent avenues to shed light on the Hubble tension, which is associated with about an $8\%$ mismatch in the value of the Hubble constant inferred…
We apply a recently demonstrated method for precision spectroscopy on strong transitions in trapped ions to measure both fine structure components of the 3s-3p transition in 24-Mg+ and 26-Mg+. We deduce absolute frequency reference data for…
Direction dependent calibration of widefield radio interferometers estimates the systematic errors along multiple directions in the sky. This is necessary because with most systematic errors that are caused by effects such as the ionosphere…
Point-wise localization of individual fluorophores is a critical step in super-resolution microscopy and single particle tracking. Although the methods are limited by the accuracy in localizing individual flourophores, this point-wise…
We point out an important source of error in measurements of extragalactic H-alpha emission and suggest ways to reduce it. The H-alpha line, used for estimating star formation rates, is commonly measured by imaging in a narrow band and a…
Continuous wavefront sensing on future space telescopes allows relaxation of stability requirements while still allowing on-orbit diffraction-limited optical performance. We consider the suitability of phase retrieval to continuously…
Review of recent works devoted to the temporal and spatial variation of the fundamental constants and dependence of the fundamental constants on the gravitational potential (violation of local position invariance) is presented. We discuss…
We present precise photometry and spectroscopy for 23 candidate spectrophotometric standard white dwarfs. The selected stars are distributed in the Northern hemisphere and around the celestial equators and are all fainter than r ~ 16.5 mag.…
This paper discusses the Cosmic Background (CB) dipoles observations in the framework of the Planck mission. Dipoles observations can be used in three ways: (i) It gives a measurement of the peculiar velocity of our Galaxy which is an…
Primordial evaluations of the deuterium abundance should provide one of the best tests of Big Bang nucleosynthesis models. Space as well as ground based observations seem however to result in different values. This asks for more…