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By confronting the two independent Boltzmann codes CLASS and CAMB, we establish that for concordance cosmology and for a given recombination history, lensed CMB and matter power spectra can be computed by current codes with an accuracy of…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 Julien Lesgourgues

The periodic solution of the Friedmann equation in conformal time, implies that only cosmological perturbations exhibiting corresponding symmetries are physically permissible, leading to a discrete spectrum of allowed wave vectors.…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-15 Wei-Ning Deng , Will Handley

In this work we analyze the full linear behaviour of the constrained interacting dark energy (CIDER) model, which is a conformally coupled quintessence model tailored to mimic a $\Lambda$CDM expansion. We compute the matter and temperature…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-18 Bruno J. Barros , Diogo Castelão , Vitor da Fonseca , Tiago Barreiro , Nelson J. Nunes , Ismael Tereno

The atomic recombination process leads to a softening of the matter equation of state as reflected by a reduced generalized adiabatic index, with accompanying heat release. We study the effects of this recombination softening and reheating…

Astrophysics · Physics 2009-08-20 Po Kin Leung , Chi-Wang Chan , Ming-Chung Chu

In this paper, we provide the first computations for the distortion transfer functions of the cosmic microwave background (CMB) in the perturbed Universe, following up on paper I and II in this series. We illustrate the physical effects…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-07 Thomas Kite , Andrea Ravenni , Jens Chluba

As atoms formed for the first time during primordial recombination, they emitted bound-bound and free-bound radiation leading to spectral distortions to the cosmic microwave background. These distortions might become observable in the…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-21 Yacine Ali-Haïmoud

We investigate the problem of reconstructing signals from a subsampled convolution of their modulated versions and a known filter. The problem is studied as applies to specific imaging systems relying on spatial phase modulation by randomly…

Information Theory · Computer Science 2016-03-23 Sohail Bahmani , Justin Romberg

We develop a new method to reconstruct the power spectrum of primordial curvature perturbations, $P(k)$, by using both the temperature and polarization spectra of the cosmic microwave background (CMB). We test this method using several mock…

Astrophysics · Physics 2009-10-09 Noriyuki Kogo , Misao Sasaki , Jun'ichi Yokoyama

We describe an attempt to reconstruct the initial conditions for the formation of cosmological large-scale structure. The power spectrum of the primordial fluctuations is affected by bias, nonlinear evolution and redshift-space distortions,…

Astrophysics · Physics 2015-06-24 J. A. Peacock , S. J. Dodds

Using the most recent data from the WMAP, ACT and SPT experiments, we update the constraints on models with oscillatory features in the primordial power spectrum of scalar perturbations. This kind of features can appear in models of…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Micol Benetti , Stefania Pandolfi , Massimiliano Lattanzi , Matteo Martinelli , Alessandro Melchiorri

Pursuing the original idea proposed in our previous paper (Paper I), we improve the method to determine the shape of the initial curvature perturbation spectrum $P(k)$ from the CMB data. The thickness of the last scattering surface (LSS)…

Astrophysics · Physics 2009-10-09 Makoto Matsumiya , Misao Sasaki , Jun'ichi Yokoyama

We investigate a phenomenological extension of the standard $\Lambda$CDM framework, the $\Omega_1\Omega_2$-$\Lambda$CDM model, in which the total energy density of the universe is expanded in powers of $1+z$. This parameterization recovers…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-20 Suresh Kumar

We use the WMAP 7 data to place constraints on oscillations supplementing an almost scale-invariant primordial power spectrum. Such oscillations are predicted by a variety of models, some of which amount to assuming there is some…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 P. Daniel Meerburg , Ralph Wijers , Jan Pieter van der Schaar

We obtain the reduced CMB data $\{l_A, R, z_*\}$ from WMAP9, WMAP9+BICEP2, Planck+WP and Planck+WP+BICEP2 for the $\Lambda$CDM and $w$CDM models with or without spatial curvature. We then use these reduced CMB data in combination with…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-06 Rong-Gen Cai , Zong-Kuan Guo , Bo Tang

With the recently published Cosmic Microwave Background data from Planck we address the optimized binning of the primordial power spectrum. As an important modification to the usual binning of the primordial spectrum, along with the…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-06 Dhiraj Kumar Hazra , Arman Shafieloo , George F. Smoot

The primordial power spectrum describes the initial perturbations in the Universe which eventually grew into the large-scale structure we observe today, and thereby provides an indirect probe of inflation or other structure-formation…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-11 Paniez Paykari , Andrew H. Jaffe

We investigate a set of cosmological models for which the primordial power spectrum has a large-scale power deficit. The standard power-law spectrum is subject to long-wavelength modifications described by some new parameters, resulting in…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-13 Sandro D. P. Vitenti , Patrick Peter , Antony Valentini

We analyse the constraints that can be placed on a cosmological constant or quintessence-like component by combining observations of Type Ia supernovae with measurements of anisotropies in the cosmic microwave background. We use the recent…

Astrophysics · Physics 2009-10-31 G. Efstathiou

We investigate the question of how tightly we can constrain the cosmological parameters by using the ``cosmic inversion'' method in which we directly reconstruct the power spectrum of primordial curvature perturbations, $P(k)$, from the…

Astrophysics · Physics 2009-10-09 Noriyuki Kogo , Misao Sasaki , Jun'ichi Yokoyama

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