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Fluctuations in the CMB have now been detected over a wide range of angular scales, and a consistent picture seems to be emerging. The data cannot currently constrain a large number of cosmological parameters, but it is clear that there is…

Astrophysics · Physics 2009-09-25 Douglas Scott , Martin White

We investigate constraints on the time variation of the fine structure constant between the recombination epoch and the present epoch, \Delta\alpha/\alpha \equiv (\alpha_{rec} - \alpha_{now})/\alpha_{now}, from cosmic microwave background…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Masahiro Nakashima , Kazuhide Ichikawa , Ryo Nagata , Jun'ichi Yokoyama

Despite the success of the standard $\Lambda$CDM model of cosmology, recent data improvements have made tensions emerge between low- and high-redshift observables, most importantly in determinations of the Hubble constant $H_0$ and the…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-18 Michael Rashkovetskyi , Julian B. Muñoz , Daniel J. Eisenstein , Cora Dvorkin

We derive the full set of second-order equations governing the evolution of cosmological perturbations, including the effects of the first-order electron number density perturbations, \delta_e. We provide a detailed analysis of the…

Astrophysics · Physics 2009-09-28 Leonardo Senatore , Svetlin Tassev , Matias Zaldarriaga

In the light of the recent Boomerang and Maxima observations of the CMB which show an anomalously low second acoustic peak, we reexamine the prediction by Adams et al (1997) that this would be the consequence of a 'step' in the primordial…

Astrophysics · Physics 2019-08-17 J. Barriga , E. Gaztanaga , M. G. Santos , S. Sarkar

The locations and amplitudes of three acoustic peaks and two dips in the last releases of the Boomerang, MAXIMA and DASI measurements of the cosmic microwave background (CMB) anisotropy power spectra as well as their statistical confidence…

Astrophysics · Physics 2009-11-07 R. Durrer , B. Novosyadlyj , S. Apunevych

The cosmic microwave background (CMB) temperature, $T$, surely the most precisely measured cosmological parameter, has been inferred from {\it local} measurements of the blackbody spectrum to an exquisite precision of 1 part in $\sim 4700$.…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-04 Meir Shimon , Yoel Rephaeli

Small-scale inhomogeneities in the baryon density around recombination have been proposed as a solution to the tension between local and global determinations of the Hubble constant. These baryon clumping models make distinct predictions…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-29 Leander Thiele , Yilun Guan , J. Colin Hill , Arthur Kosowsky , David N. Spergel

We discuss the cosmological degeneracy between the Hubble parameter H(z), the age of the universe and cosmological parameters describing simple variations from the minimal LCDM model. We show that independent determinations of the Hubble…

Astrophysics · Physics 2014-11-18 Daniel G. Figueroa , Licia Verde , Raul Jimenez

The HeII->HeI recombination of primordial helium plasma (z = 1500 - 3000) is considered in terms of the standard cosmological model. This process affects the formation of cosmic microwave background anisotropy and spectral distortions. We…

Astrophysics · Physics 2011-08-31 E. E. Kholupenko , A. V. Ivanchik , D. A. Varshalovich

We show that by combining measurements of the temperature and polarization anisotropies of the Cosmic Microwave Background (CMB), future experiments will tightly constrain the expansion rate of the universe during recombination. A change in…

Astrophysics · Physics 2009-11-07 Oliver Zahn , Matias Zaldarriaga

The cosmic microwave background anisotropy is sensitive to the slope and amplitude of primordial energy density and gravitational wave fluctuations, the baryon density, the Hubble constant, the cosmological constant, the ionization history,…

We present cosmological constraints from a joint analysis of the pre- and post-reconstruction galaxy power spectrum multipoles from the final data release of the Baryon Oscillation Spectroscopic Survey (BOSS). Geometric constraints are…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-03 Oliver H. E. Philcox , Mikhail M. Ivanov , Marko Simonović , Matias Zaldarriaga

Anisotropies of the cosmic microwave background are thought to be due to perturbations of the primordial medium, which, post recombination, lead to the formation of galaxy clusters and galaxies. Aims: We analyse the perturbation wave modes…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-16 A. H. Nelson

We forecast the ability of future CMB and galaxy lensing surveys to constrain variations of the fine structure constant. We found that lensing data, as those expected from satellite experiments as Euclid could improve the constraint from…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Matteo Martinelli , Eloisa Menegoni , Alessandro Melchiorri

In this paper we use all available baryon acoustic oscillation, Hubble parameter, and quasar angular size data to constrain six dark energy cosmological models, both spatially flat and non-flat. Depending on the model and data combination…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-10 Joseph Ryan , Yun Chen , Bharat Ratra

We present results from the analysis of cosmic microwave background (CMB), large scale structure (galaxy redshift survey) and X-ray galaxy cluster (baryon fraction and X-ray luminosity function) data, assuming a geometrically flat…

Astrophysics · Physics 2009-11-10 S. W. Allen , R. W. Schmidt , S. L. Bridle

A new method is proposed to measure the Hubble constant H0 through the mean transmitted flux observed from high redshift quasars. A semi-analytical model for the cosmological-independent volume density distribution function is adopted which…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 V. C. Busti , R. N. Guimarães , J. A. S. Lima

We constrain cosmological parameters in flat cosmologies with tracking dark energy (or Quintessence) using the existing data on Cosmic Microwave Background (CMB) anisotropies. We perform a maximum likelihood analysis using combined data…

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