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Searches for primordial gravitational waves have resulted in constraints in a large frequency range from a variety of sources. The standard Cosmic Microwave Background (CMB) technique is to parameterise the tensor power spectrum in terms of…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-14 Thomas J. Clarke , Edmund J. Copeland , Adam Moss

The cosmic microwave background (CMB), carrying the inhomogeneous information of the very early universe, is of great significance for understanding the origin and evolution of our universe. However, observational CMB maps contain serious…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-12 Guo-Jian Wang , Hong-Liang Shi , Ye-Peng Yan , Jun-Qing Xia , Yan-Yun Zhao , Si-Yu Li , Jun-Feng Li

Voyage 2050 White Paper highlighting the unique science opportunities using spectral distortions of the cosmic microwave background (CMB). CMB spectral distortions probe many processes throughout the history of the Universe. Precision…

Measuring the primordial matter power spectrum is our primary means of probing unknown physics in the very early universe. We allow the primordial power spectrum to be an arbitrary function, and parametrize it in terms of wavelet band…

Astrophysics · Physics 2009-11-07 Pia Mukherjee , Yun Wang

Multi-field models of inflation typically assume that interactions between particles can be treated perturbatively. Strongly-coupled models provide an intriguing alternative and may offer novel inflationary phenomenology. We study the…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-27 Oliver H. E. Philcox , Guilherme L. Pimentel , Chen Yang

We study the performance of three pairs of tilted $\Lambda$CDM cosmological models, two pairs allowing for non-flat spatial hypersurfaces with CMB temperature and polarization power spectrum data (P18) from Planck, P18 lensing (lensing),…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-29 Javier de Cruz Perez , Chan-Gyung Park , Bharat Ratra

While the simplest inflationary models predict a power-law form of the primordial power spectrum (PPS), various UV complete scenarios predict features on top of the standard power law that leave characteristic imprints in the late-time…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-26 Rodrigo Calderon , Théo Simon , Arman Shafieloo , Dhiraj Kumar Hazra

We investigate the observational signatures of three models of the early Universe in the $B$-mode polarization of the Cosmic Microwave Background (CMB) radiation. In addition to the standard single field inflationary model, we also consider…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-27 Yin-Zhe Ma , Wen Zhao , Michael L. Brown

Diffusion damping of the cosmic microwave background (CMB) power spectrum results from imperfect photon-baryon coupling in the pre-recombination plasma. At redshift $5 \times 10^4 < z < 2 \times 10^6$, the plasma acquires an effective…

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

In the near future, observations of the cosmic microwave background (CMB) anisotropies will provide accurate determinations of many fundamental cosmological parameters. In this paper, we analyse degeneracies among cosmological parameters to…

Astrophysics · Physics 2009-10-30 G. Efstathiou , J. R. Bond

The standard cosmological model, LCDM, provides an excellent fit to Cosmic Microwave Background (CMB) data. However, the model has well known problems. For example, the cosmological constant, is fine-tuned to 1 part in 10^100 and the cold…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 T. Shanks , R. W. F. Johnson , J. A. Schewtschenko , J. R. Whitbourn

We undertake a thorough search for signatures of sharp oscillatory features in the WMAP9 power spectrum and bispectrum as well as in the Planck power spectrum. For the first time, we carry out searches in both the power spectrum and…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-27 J. R. Fergusson , H. F. Gruetjen , E. P. S. Shellard , B. Wallisch

When extracting cosmological information from power spectrum measurements, we must consider the impact of super-sample density fluctuations whose wavelengths are larger than the survey scale. These modes contribute to the mean density…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-03 Yin Li , Wayne Hu , Masahiro Takada

Since the measurements of COBE/FIRAS in the mid-90's we know that the energy spectrum of the cosmic microwave background (CMB) is extremely close to that of a perfect blackbody at an average temperature T0~2.726K. However, a number of…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-11 Jens Chluba

We calculate the detectability of the polarization of the cosmic microwave background (CMB) as a function of the sky coverage, angular resolution, and instrumental sensitivity for a hypothetical experiment. We consider the gradient…

Astrophysics · Physics 2009-10-31 Andrew H. Jaffe , Marc Kamionkowski , Limin Wang

We present a Gaussianity test of the cosmic microwave background (CMB) polarization by analyzing the statistics of unpolarized points in the sky, classified into three distinct types: saddles, comets, and beaks. This classification of…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-01 K. O. Parfenov , D. I. Novikov , A. O. Mihalchenko

Several missions following Planck are currently under development, which will provide high-precision measurements of the Cosmic Microwave Background (CMB) anisotropies. Specifically, measurements of the E modes will become nearly limited by…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-01 Catherine Petretti , Matteo Braglia , Xingang Chen , Dhiraj Kumar Hazra , Sonia Paban

We reconstruct the power spectrum of primordial curvature perturbations by applying a well-validated non-parametric technique employing Tikhonov regularisation to the first data release from the Planck satellite. To improve the…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-31 Paul Hunt , Subir Sarkar

It has been recently shown that cosmological models with scale-dependent primordial non-Gaussianities (sPNG) could provide a possible path to solve current cosmic tensions. Moreover, it has been pointed out that some of these models might…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-08 Clément Stahl , Benoit Famaey , Rodrigo Ibata , Katarina Kraljic , Fabien Castillo