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Following the discovery of the CMB, the hot big-bang model has become the standard cosmological model. In this theory, small primordial fluctuations are subsequently amplified by gravity to form the large-scale structure seen today.…

Astrophysics · Physics 2015-06-24 Licia Verde

Observed CMB anisotropies are lensed, and the lensed power spectra can be calculated accurately assuming the lensing deflections are Gaussian. However, the lensing deflections are actually slightly non-Gaussian due to both non-linear…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-12 Antony Lewis , Geraint Pratten

Galilean Genesis is generically plagued with a strong coupling problem, but this can be avoided depending on the hierarchy between a classical energy scale of genesis and a strong coupling scale. In this paper, we investigate whether or not…

General Relativity and Quantum Cosmology · Physics 2023-03-15 Shingo Akama , Shin'ichi Hirano

Primordial non-Gaussianity arising from inflationary models is a unique probe of non-trivial dynamics of the inflaton field and its interactions with other fields. Often when examining and constraining the scalar non-Gaussianity arising…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-17 Barnali Das , H. V. Ragavendra

The abundance of clusters and the clustering of galaxies are two of the important cosmological probes for current and future large scale surveys of galaxies, such as the Dark Energy Survey. In order to combine them one has to account for…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-17 Fabien Lacasa , Rogerio Rosenfeld

Primordial magnetic fields lead to non-Gaussian signals in the Cosmic Microwave Background (CMB) even at the lowest order, as magnetic stresses, and the temperature anisotropy they induce, depend quadratically on the magnetic field. In…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-03 T. R. Seshadri , Kandaswamy Subramanian

We discuss Cosmic Microwave Background constraints on the causal set theory of quantum gravity, which has made testable predictions about the nature of dark energy. We flesh out previously discussed heuristic constraints by showing how the…

Astrophysics · Physics 2008-11-26 Joe Zuntz

In this paper we propose a new statistic capable of detecting non-Gaussianity in the CMB. The statistic is defined in Fourier space, and therefore naturally separates angular scales. It consists of taking another Fourier transform, in…

Astrophysics · Physics 2010-04-08 Alex Lewin , Andreas Albrecht , Joao Magueijo

CMB and lensing reconstruction power spectra are powerful probes of cosmology. However they are correlated, since the CMB power spectra are lensed and the lensing reconstruction is constructed using CMB multipoles. We perform a full…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-20 Julien Peloton , Marcel Schmittfull , Antony Lewis , Julien Carron , Oliver Zahn

Any hint of non-gaussianity in the cosmological initial conditions will provide us with a unique window into the physics of early universe. We show that the impact of a small local primordial non-gaussianity (generated on super-horizon…

Astrophysics · Physics 2008-12-18 Niayesh Afshordi , Andrew J. Tolley

As the era of high precision cosmology approaches, the empirically determined power spectrum of the microwave background anisotropy $C_l$ will provide a crucial test for cosmological theories. We present an exact semi-analytic framework for…

Astrophysics · Physics 2015-06-24 Benjamin D. Wandelt , Eric Hivon , Krzysztof M. Gorski

Forthcoming radio continuum surveys will cover large volumes of the observable Universe and will reach to high redshifts, making them potentially powerful probes of dark energy, modified gravity and non-Gaussianity. Here we extend recent…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-12 Roy Maartens , Gong-Bo Zhao , David Bacon , Kazuya Koyama , Alvise Raccanelli

As galaxy surveys become more precise and push to smaller scales, the need for accurate covariances beyond the classical Gaussian formula becomes more acute. Here, I investigate the analytical implementation and impact of non-Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-12 Fabien Lacasa

The non-Gaussianity of inflationary perturbations, as encoded in the bispectrum (or 3-point correlator), has become an important additional way of distinguishing between inflation models, going beyond the linear Gaussian perturbation…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-23 Bartjan van Tent

It is known that some cosmological perturbations are conformal invariant. This facilitates the studies of perturbations within some gravitational theories alternative to general relativity, for example the scalar-tensor theory, because it…

General Relativity and Quantum Cosmology · Physics 2015-10-21 Mingzhe Li , Yicen Mou

The likelihood function is a crucial element of parameter estimation. In analyses of galaxy overdensities and weak lensing shear, one often approximates the likelihood of the power spectrum with a Gaussian distribution. The posterior…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 L. Sun , Q. Wang , H. Zhan

The stochastic gravitational-wave background originating from cosmic sources contains vital information about the early universe. In this work, we comprehensively study the cross-correlations between the energy-density anisotropies in…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-16 Zhi-Chao Zhao , Sai Wang , Jun-Peng Li , Kazunori Kohri

Several recent studies have shown how to properly calculate the observed clustering of galaxies in a relativistic context, and uncovered corrections to the Newtonian calculation that become significant on scales near the horizon. Here, we…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Donghui Jeong , Fabian Schmidt , Christopher M. Hirata

We describe how to compute estimates of the power spectrum C_l from Cosmic Microwave Background (CMB) maps that not only retain all the cosmological information, but also have uncorrelated error bars and well-behaved window functions. We…

Astrophysics · Physics 2007-05-23 Max Tegmark , Andrew Hamilton

We forecast constraints on primordial non-Gaussianity (PNG) and bias parameters from measurements of galaxy power spectrum and bispectrum in future radio continuum and optical surveys. In the galaxy bispectrum, we consider a comprehensive…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-04 Dionysios Karagiannis , Andrei Lazanu , Michele Liguori , Alvise Raccanelli , Nicola Bartolo , Licia Verde