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We present updated constraints on the variation of the fine structure constant, $\alpha_{\rm EM}$, and effective electron rest mass, $m_{\rm e}$, during the cosmological recombination era. These two fundamental constants directly affect the…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-25 Luke Hart , Jens Chluba

We derive constraints on cosmological parameters using the power spectrum of galaxy clustering measured from the final two-degree field galaxy redshift survey (2dFGRS) and a compilation of measurements of the temperature power spectrum and…

We constrain flat cosmological models with a joint likelihood analysis of a new compilation of data from the cosmic microwave background (CMB) and from the 2dF Galaxy Redshift Survey (2dFGRS). Fitting the CMB alone yields a known degeneracy…

Observational constraints guide one forcefully to examine models in which the matter density is substantially less than critical density. Particularly noteworthy are those which are consistent with inflation. For these models, microwave…

Astrophysics · Physics 2007-05-23 J. P. Ostriker , Paul J. Steinhardt

The Standard Cosmological Model has experienced tremendous success at reproducing observational data by assuming a universe dominated by a cosmological constant and dark matter in a flat geometry. However, several studies, based on local…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-29 Jailson S. Alcaniz , Jacinto P. Neto , Farinaldo S. Queiroz , Deivid R. da Silva , Raimindo Silva

We present results for the spectral distortions of the Cosmic Microwave Background (CMB) arising due to bound-bound transitions during the epoch of cosmological hydrogen recombination at frequencies down to nu~100MHz. We extend our previous…

Astrophysics · Physics 2009-09-29 J. Chluba , J. A. Rubino-Martin , R. A. Sunyaev

We present a method for calculating large numbers of power spectra C_l and P(k) that accelerates CMBfast by a factor around 10^3 without appreciable loss of accuracy, then apply it to constrain 11 cosmological parameters from current Cosmic…

Astrophysics · Physics 2009-10-07 Max Tegmark , Matias Zaldarriaga , Andrew J. S. Hamilton

A key prediction of cosmological theories for the origin and evolution of structure in the Universe is the existence of a `Doppler peak' in the angular power spectrum of cosmic microwave background (CMB) fluctuations. We present new results…

Astrophysics · Physics 2020-11-25 S. Hancock , G. Rocha , A. N. Lasenby , C. M. Gutierrez

We solve the recombination equation by taking into account the induced recombinations and a physical cut off in the hydrogen spectrum. The effective recombination coefficient is parametrized as a function of temperature and free electron…

Astrophysics · Physics 2008-02-03 Peter Boschan , Peter Biltzinger

Measurements of the Cosmic Microwave Background Radiation (CMBR) provide a powerful tool for measuring the primary cosmological parameters. However, there is a large degree of parameter degeneracy in simultaneous measurements of the matter…

Astrophysics · Physics 2016-08-30 Steen Hannestad

We have performed the most comprehensive predictions of the temperature fluctuations \dtt in the primeval isocurvature baryon models to see whether or not the models are consistent with the recent data on the cosmic microwave background…

Astrophysics · Physics 2009-10-22 Takashi Chiba , Naoshi Sugiyama , Yasushi Suto

It is well known that estimating cosmological parameters from cosmic microwave background (CMB) data alone results in a significant degeneracy between the total neutrino mass and several other cosmological parameters, especially the Hubble…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-28 Will Sutherland

The recombination of hydrogen and helium at z~1000-7000 gives unavoidable distortions to the Cosmic Microwave Background (CMB) spectrum. We present a detailed calculation of the line intensities arising from the Ly-alpha (2p-1s) and…

Astrophysics · Physics 2009-11-13 Wan Yan Wong , Sara Seager , Douglas Scott

In recent years, upper limits on the cosmic microwave background (CMB) anisotropies combined with predictions made by theories of galaxy formation, have been extremely powerful in ruling out purely baryonic dark matter (BDM) universes.…

Astrophysics · Physics 2009-11-06 Louise M Griffiths , Alessandro Melchiorri , Joseph Silk

We address the possibility of bounding the spectral index $n$ of primordial density fluctuations, using both the cosmic microwave background (cmb) anisotropy and data on galaxies and clusters. Each piece of galaxy and cluster data is…

Astrophysics · Physics 2008-02-03 Andrew R Liddle , David H Lyth

The pattern of acoustic peaks in the sub-horizon power spectrum of primordial density anisotropies at recombination can be naturally understood in the framework of standard Friedmann-Robertson-Walker cosmology (without inflation) as a…

General Relativity and Quantum Cosmology · Physics 2007-05-23 David H. Oaknin

We introduce a simple yet powerful {\it analytic} method which obtains the structure of cosmic microwave background anisotropies to better than 5-10\% in temperature fluctuations on {\it all} scales. It is applicable to {\it any} model in…

Astrophysics · Physics 2009-07-17 Wayne Hu , Naoshi Sugiyama

Cosmic microwave background (CMB) anisotropies and density fluctuations are calculated for flat cold dark matter (CDM) models with a wide range of parameters, i.e., $\Omega_0, h$ and $\Omega_B$ for both standard recombination and various…

Astrophysics · Physics 2009-10-22 Naoshi Sugiyama

The value of the Hubble constant determined from CMB and BAO measurements is directly dependent on the sound horizon at the photon-baryon decoupling. There has been significant interest in the possibility of new physics at the epoch around…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-05 Levon Pogosian , Gong-Bo Zhao , Karsten Jedamzik

We devise a measure n(r) to quantify a robust feature in the coherent cosmic perturbations, namely the narrowness of the first peak in the power spectrum of the Cosmic Microwave Background (CMB) anisotropy. A maximum-likelihood analysis…

Astrophysics · Physics 2007-05-23 Jiun-Huei Proty Wu