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If dark matter decays to electromagnetically-interacting particles, it can inject energy into the baryonic gas and thus affect the processes of recombination and reionization. This leaves an imprint on the cosmic microwave background (CMB):…

Astrophysics · Physics 2008-11-26 Le Zhang , Xuelei Chen , Marc Kamionkowski , Zongguo Si , Zheng Zheng

We present measurements of large-scale cosmic microwave background (CMB) E-mode polarization from the Cosmology Large Angular Scale Surveyor (CLASS) 90 GHz data. Using 115 det-yr of observations collected through 2024 with a variable-delay…

The cosmic microwave background (CMB) anisotropies have turned out to represent one of the most stringent 'bottle necks' for scenarios of large scale structure formation. As a possibility to relax this constraint, it has been proposed that…

Astrophysics · Physics 2009-10-22 Ruth Durrer

(abridged) We study the impact of the large-angle CMB polarization datasets publicly released by the WMAP and Planck satellites on the estimation of cosmological parameters of the $\Lambda$CDM model. To complement large-angle polarization,…

Inhomogeneous reionization gives rise to angular fluctuations in the Cosmic Microwave Background (CMB) optical depth tau(n) to the last scattering surface, correlating different spherical harmonic modes and imprinting characteristic…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-24 Meng Su , Amit P. S. Yadav , Matthew McQuinn , Jaiyul Yoo , Matias Zaldarriaga

Recent Cosmic Microwave Background (CMB) temperature and polarization anisotropy measurements from the Planck mission have significantly improved previous constraints on the neutrino masses as well as the bounds on extended models with…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-20 Eleonora Di Valentino , Elena Giusarma , Olga Mena , Alessandro Melchiorri , Joseph Silk

We consider the prospects of probing features in the primordial power spectrum with future Cosmic Microwave Background (CMB) polarization measurements. In the scope of the inflationary scenario, such features in the spectrum can be produced…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-05 Dhiraj Kumar Hazra , Daniela Paoletti , Mario Ballardini , Fabio Finelli , Arman Shafieloo , George F. Smoot , Alexei A. Starobinsky

We derive updated Cosmic Microwave Background (CMB) constraints on annihilating dark matter, and present forecasts for upcoming CMB surveys. We show that the addition of recent temperature, polarization, and lensing data from ground-based…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-12 Charlotte Myers , Dominic Agius , Daniele Gaggero , Angelo Ricciardone

The Planck experiment has measured the Cosmic Microwave Background (CMB) angular spectrum with unprecedented accuracy, and these results are likely to remain the state-of-the art for a decade or more. Since these measurements are going to…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-17 Julia Stadler , Céline Bœhm

Since the temperature fluctuations in cosmic microwave background (CMB) on large-angular scales probe length scales that were super-horizon sized at photon decoupling and hence insensitive to microphysical processes, the low-multipole CMB…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-30 Cheng Cheng , Qing-Guo Huang

We perform an analysis of the recent WMAP7 data considering physically motivated and viable reionization scenarios with the aim of assessing their effects on cosmological parameter determinations. The main novelties are: (i) the combination…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-29 Stefania Pandolfi , Andrea Ferrara , T. Roy Choudhury , Alessandro Melchiorri , Sourav Mitra

One of the main goals of modern cosmic microwave background (CMB) missions is to measure the tensor-to-scalar ratio $r$ accurately to constrain inflation models. Due to ignorance about the reionization history $X_{e}(z)$, this analysis is…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-03 King Lau , Jiayu Tang , M. -C. Chu

At wavelengths longer than 21 cm, photons from the long-wavelength tail of the cosmic microwave background (CMB) have a non-zero probability of being absorbed by distant neutral hydrogen. This provides an additional suppression of the…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-25 Gilbert Holder , Adrian Liu , Tzu-Ching Chang , David Zegeye

Recently, the James Webb Space Telescope (JWST) has found early galaxies producing photons from more efficient ionization than previously assumed. This may suggest a reionization process with a larger reionization optical depth, $\tau_{\rm…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-28 Itamar J. Allali , Praniti Singh , JiJi Fan , Lingfeng Li

We demonstrate that the cosmic microwave background (CMB) temperature-polarization cross-correlation provides accurate and robust constraints on cosmological parameters. We compare them with the results from temperature or polarization and…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-07 F. Couchot , S. Henrot-Versillé , O. Perdereau , S. Plaszczynski , B. Rouillé d'Orfeuil , M. Spinelli , M. Tristram

The standard cosmological model, with its six independent parameters, successfully describes our observable Universe. One of these parameters, the optical depth to reionization $\tau_\mathrm{reio}$, represents the scatterings that Cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-06 Paulo Montero-Camacho , Yin Li , Miles Cranmer

We study the anisotropy of the cosmic microwave background (CMB) in cold and mixed dark matter (CDM and MDM) models, with non scale-invariant primordial power spectra (i.e. $n \neq 1$) and a late, sudden reionization of the intergalactic…

We review aspects of Cosmic Microwave Background (CMB) spectral distortions which do not appear to have been fully explored in the literature. In particular, implications of recent evidences of heating of the intergalactic medium (IGM) by…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-13 G. De Zotti , M. Negrello , G. Castex , A. Lapi , M. Bonato

Recent studies report a mild discrepancy between baryon acoustic oscillation (BAO) and cosmic microwave background (CMB) measurements within the $\Lambda$CDM framework. This discrepancy could be explained if the optical depth $\tau$…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-15 Yuta Kageura , Masami Ouchi , Fumihiro Naokawa , Hiroya Umeda , Akinori Matsumoto , Yuichi Harikane , Minami Nakane , Tran Thi Thai

In an earlier paper (Cen 2003) we pointed out the strong likelihood for the universal reionization to occur twice, giving rise to a larger Thomson optical depth. Here we perform a more focused analysis of the Thomson optical depth in light…

Astrophysics · Physics 2009-11-07 Renyue Cen