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We focus on uncertainties in supernova measurements, in particular of individual magnitudes and redshifts, to review to what extent supernovae measurements of the expansion history of the universe are likely to allow us to constrain a…

Astrophysics · Physics 2011-05-12 Lawrence M. Krauss , Katherine Jones-Smith , Dragan Huterer

A high resolution 2 m$^2$ tracking detector, based on timing Resistive Plate Chamber (tRPC) cells, has been installed at the Faculty of Physics of the University of Santiago de Compostela (Spain) in order to improve our understanding of the…

Instrumentation and Methods for Astrophysics · Physics 2020-07-14 Irma Riádigos , Damián García-Castro , Diego González-Díaz , Vicente Pérez-Muñuzuri

I briefly review the cosmological constant problem and the issue of dark energy (or quintessence). Within the framework of quantum field theory, the vacuum expectation value of the energy momentum tensor formally diverges as $k^4$. A cutoff…

Astrophysics · Physics 2008-11-26 Varun Sahni

We present a detailed analysis of present and future Cosmic Microwave Background constraints of the value of the fine-structure constant, $\alpha$. We carry out a more detailed analysis of the WMAP first-year data, deriving state-of-the-art…

We study dynamics of $\Lambda(t)$ cosmological models which are a natural generalization of the standard cosmological model (the $\Lambda$CDM model). We consider a class of models: the ones with a prescribed form of…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-29 Marek Szydlowski , Aleksander Stachowski

Temperature maps of the Cosmic Microwave Background (CMB) radiation, as those obtained by the Wilkinson Microwave Anisotropy Probe (WMAP), provide one of the most precise data sets to test fundamental hypotheses of modern cosmology. One of…

Astrophysics · Physics 2009-11-13 Armando Bernui , Constantino Tsallis , Thyrso Villela

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 success of precision cosmology depends not only on accurate observations, but also on the theoretical model - which must be understood to at least the same level of precision. Subtle relativistic effects can lead to biased measurements…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Chris Clarkson , Obinna Umeh , Roy Maartens , Ruth Durrer

Redshift is a key quantity for inferring cosmological model parameters. In photometric redshift estimation, cosmologists use the coarse data collected from the vast majority of galaxies to predict the redshift of individual galaxies. To…

Applications · Statistics 2016-04-07 Rafael Izbicki , Ann B. Lee , Peter E. Freeman

In this paper, we explain how moments of the thermal Sunyaev-Zel'dovich (tSZ) effect can constrain both cosmological parameters and the astrophysics of the intracluster medium (ICM). As the tSZ signal is strongly non-Gaussian, higher…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 J. Colin Hill , Blake D. Sherwin

We use a compilation of cosmic microwave anisotropy data to constrain the epoch of reionization in the Universe, as a function of cosmological parameters. We consider spatially-flat cosmologies, varying the matter density $\Omega_0$ (the…

Astrophysics · Physics 2009-10-31 Louise M Griffiths , Domingos Barbosa , Andrew R Liddle

A hypothetical dark energy component may have an equation of state that is different from a cosmological constant and possibly even changing in time. The spacing of the cosmic microwave background peaks is sensitive to the ratio of the…

Astrophysics · Physics 2007-05-23 Michael Doran , Matthew Lilley , Jan Schwindt , Christof Wetterich

It has been hypothesized that the cosmic microwave background (CMB) provides a temperature floor for collapsing protostars that can regulate the process of star formation and result in a top-heavy initial mass function at high metallicity…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Jeremy Bailin , Greg Stinson , Hugh Couchman , William E. Harris , James Wadsley , Sijing Shen

Most cosmological constraints on modified gravity are obtained assuming that the cosmic evolution was standard $\Lambda$CDM in the past and that the present matter density and power spectrum normalization are the same as in a $\Lambda$CDM…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Laura Taddei , Luca Amendola

Cosmography is a phenomenological and relatively model-independent approach to cosmology, where physical quantities are expanded as a Taylor series in the cosmological redshift, or in related variables. Here we apply this methodology to…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-08 C. J. A. P. Martins , F. P. S. A. Ferreira , P. V. Marto

In the recent preprint arXiv:2604.07244v1, the authors introduce a novel combination of redshift, distance, and expansion rate observables for constraining cosmic backreaction. The current work presents a first application of the method,…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-14 S. M. Koksbang

We present an Effective Field Theory based reconstruction of quintessence models of dark energy directly from cosmological data. We show that current cosmological data possess enough constraining power to test several quintessence model…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-26 Minsu Park , Marco Raveri , Bhuvnesh Jain

A priori, cosmic-ray measurements offer a unique capability to determine the vertical profile of atmospheric temperatures directly from ground. However, despite the increased understanding of the impact of the atmosphere on cosmic-ray…

Atmospheric and Oceanic Physics · Physics 2021-12-10 Riádigos Irma , González-Díaz Diego , Pérez-Muñuzuri Vicente

We propose a new analysis of small scale CMB data by introducing the cosmological dependency of the foreground signals, focusing first on the thermal Sunyaev-Zel'dovich (tSZ) power spectrum, derived from the halo model. We analyse the…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-22 Marian Douspis , Laura Salvati , Adélie Gorce , Nabila Aghanim