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Related papers: Isocurvature forecast in the anthropic axion windo…

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We use cosmological observations in the post-Planck era to derive limits on thermally produced cosmological axions. In the early universe such axions contribute to the radiation density and later to the hot dark matter fraction. We find an…

Cosmology and Nongalactic Astrophysics · Physics 2015-02-02 Maria Archidiacono , Steen Hannestad , Alessandro Mirizzi , Georg Raffelt , Yvonne Y. Y. Wong

We explore the qualitative changes that would occur if the amplitude Q ~ 10^{-5} of cosmological density fluctuations were different. If is less than about 10^{-6}, the cosmological objects that form would have so low virial temperatures…

Astrophysics · Physics 2009-10-07 Max Tegmark , Martin Rees

There is an approximately 9% discrepancy, corresponding to 2.4sigma, between two independent constraints on the expansion rate of the universe: one indirectly arising from the cosmic microwave background and baryon acoustic oscillations,…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-17 Valerio Marra , Luca Amendola , Ignacy Sawicki , Wessel Valkenburg

We establish a relationship between the multipoles of the expansion rate fluctuation field $\eta,$ which capture in an accurate way deviations from isotropy in the redshift-distance relation, and the multipoles of the covariant cosmographic…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-06 Basheer Kalbouneh , Christian Marinoni , Roy Maartens

Our motion relative to the cosmic-microwave-background (CMB) rest frame deflects light rays giving rise to shifts as large as L -> L(1+beta), where beta=0.00123 is our velocity (in units of the speed of light) on measurements CMB…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-22 Donghui Jeong , Jens Chluba , Liang Dai , Marc Kamionkowski , Xin Wang

The origin of small deviations from statistical isotropy in the Cosmic Microwave Background (CMB) - the so-called CMB anomalies - remains an open question in modern cosmology. In this work, we test statistical isotropy in Planck Data…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-09 C. Gimeno-Amo , F. K. Hansen , E. Martínez-González , R. B. Barreiro , A. J. Banday

The fraction of matter that is in the form of baryons or dark matter could have spatial fluctuations in the form of baryon-dark matter isocurvature fluctuations. We use big bang nucleosynthesis calculations compared with observed light…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Gilbert P. Holder , Kenneth M. Nollett , Alexander van Engelen

A spherical cosmological model with a local void on scales of $\sim 200$ Mpc and with an inhomogeneous Hubble constant was proposed in recent two papers. This model explains consistently the observed properties of the cosmic bulk flow, the…

Astrophysics · Physics 2009-10-31 Kenji Tomita

We show that the upper bound of the classical QCD axion window can be significantly relaxed for low-scale inflation. If the Gibbons-Hawking temperature during inflation is lower than the QCD scale, the initial QCD axion misalignment angle…

High Energy Physics - Phenomenology · Physics 2018-08-02 Fuminobu Takahashi , Wen Yin , Alan H. Guth

The angular power spectrum of the cosmic microwave background temperature anisotropy observed by WMAP has an anomalous dip at l~20 and bump at l~40. One explanation for this structure is the presence of features in the primordial curvature…

Cosmology and Nongalactic Astrophysics · Physics 2009-05-19 Michael J. Mortonson , Cora Dvorkin , Hiranya V. Peiris , Wayne Hu

We investigate the cosmic variance of the skewness of the cosmic microwave background (CMB) anisotropies in an inflationary model which leads to the baryon isocurvature scenario for the cosmic structure formation. In this model, the baryon…

Astrophysics · Physics 2016-08-30 Kazuhiro Yamamoto , Misao Sasaki

Cosmological colliders can preserve information from interactions at very high energy scale, and imprint them on cosmological observables. Taking the squeezed limit of cosmological perturbation bispectrum, information of the intermediate…

High Energy Physics - Theory · Physics 2022-06-07 Shiyun Lu

We consider the evolution of the Affleck-Dine scalar during D-term and F-term inflation and solve the combined slow-roll equations of motion. We show that for a typical case, where both the Affleck-Dine scalar and inflaton initially have…

High Energy Physics - Phenomenology · Physics 2009-10-31 Kari Enqvist , John McDonald

We present a joint analysis of the CMB lensing power spectra measured from the Data Release 6 of the Atacama Cosmology Telescope and Planck PR4, cross-correlations between the ACT and Planck lensing reconstruction and galaxy clustering from…

The statistical uncertainty in measuring the primordial density perturbations on a given comoving scale is dictated by the number of independent regions of that scale that are accessible to an observer. This number varies with cosmic time…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Abraham Loeb

In light of the most recent cosmological observations, we provide new updated constraints on the slow-roll inflation in different extended scenarios beyond the $\Lambda\rm{CDM}$ cosmological model. Along with the usual six parameters, we…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-25 Matteo Forconi , William Giarè , Eleonora Di Valentino , Alessandro Melchiorri

We investigate cosmological constraints on primordial isocurvature and tensor perturbations, using recent observations of the cosmic microwave background and the large scale structure. We find that present observations are consistent with…

Astrophysics · Physics 2009-06-23 Masahiro Kawasaki , Toyokazu Sekiguchi

Independent tests aiming to constrain the value of the cosmological constant $\Lambda$ are usually difficult because of its extreme smallness $\left(\Lambda \simeq 1\times 10^{-52}~\textrm{m}^{-2},~\textrm{or}~2.89\times…

General Relativity and Quantum Cosmology · Physics 2018-03-28 Lorenzo Iorio

Inflation creates large-scale cosmological density perturbations that are characterized by an isotropic, homogeneous, and Gaussian random distribution about a locally flat background. Even in a flat universe, the spatial curvature measured…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Matthew Kleban , Marjorie Schillo

In universes with significant curvature or cosmological constant, cosmic microwave background (CMB) anisotropies are created very recently via the Rees-Sciama or integrated Sachs-Wolfe effects. This causes the CMB anisotropies to become…

Astrophysics · Physics 2009-10-30 S. P. Boughn , R. G. Crittenden , N. G. Turok