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Current cosmological observations point to a serious discrepancy between the observed Hubble parameter obtained using direct and cosmic microwave background radiation (CMBR) measurements. Besides this, the so called Hubble--Lema\^itre…

宇宙学与河外天体物理 · 物理学 2022-01-20 Prabhakar Tiwari , Rahul Kothari , Pankaj Jain

We consider cosmic microwave background (CMB) anisotropy in models with quintessence taking into account of isocurvature fluctuation in the quintessence. It is shown that, if the primordial fluctuation of the quintessence has a correlation…

高能物理 - 唯象学 · 物理学 2007-05-23 Takeo Moroi , Tomo Takahashi

We introduce a new family of primordial cosmological perturbations that are not described by traditional power spectra. At the linear level, these perturbations live in the kernel of the spatial Laplacian operator, and thus we call them…

宇宙学与河外天体物理 · 物理学 2018-08-08 Niayesh Afshordi , Matthew C. Johnson

The role of cosmic microwave background (CMB) polarisation data in constraining the presence of primordial isocurvature modes is examined. While the MAP satellite mission will be unable to simultaneously constrain isocurvature modes and…

天体物理学 · 物理学 2009-10-31 M Bucher , K Moodley , N Turok

Cosmic inflation, a period of accelerated expansion in the early universe, can give rise to large amplitude ultra-large scale inhomogeneities on distance scales comparable to or larger than the observable universe. The cosmic microwave…

宇宙学与河外天体物理 · 物理学 2017-08-09 Jonathan Braden , Matthew C. Johnson , Hiranya V. Peiris , Anthony Aguirre

We show that intrinsic (not lensing-induced) correlations between galaxy shapes offer a new probe of primordial non-Gaussianity and inflationary physics which is complementary to galaxy number counts. Specifically, intrinsic alignment…

宇宙学与河外天体物理 · 物理学 2016-03-25 Fabian Schmidt , Nora Elisa Chisari , Cora Dvorkin

It is generally accepted that the observed CMBR dipole arises from the motion of the local group relative to the CMBR frame. An alternative interpretation is that the dipole results from an ultra-large scale ($\lambda > 100 c/H_0)$…

天体物理学 · 物理学 2009-10-28 David Langlois , Tsvi Piran

Discrepancy between the measurements of Hubble constant $H_{0}$ from the cosmic microwave background (CMB) and the local distance ladder is the most serious challenge to the standard $\Lambda$CDM model. Recent researches point out that it…

宇宙学与河外天体物理 · 物理学 2024-10-10 J. P. Hu , X. D. Jia , J. Hu , F. Y. Wang

The curl-modes of Cosmic Microwave Background (CMB) polarization probe horizon-scale primordial gravitational waves related to inflation. A significant source of confusion is expected from a lensing conversion of polarization related to…

天体物理学 · 物理学 2009-11-10 Asantha Cooray

We explicate the origin of the temperature quadrupole in the adiabatic dark energy model and explore the mechanism by which scale invariant isocurvature dark energy perturbations can lead to its sharp suppression. The model requires…

天体物理学 · 物理学 2011-05-12 Christopher Gordon , Wayne Hu

We present the first joint analysis of catalogs of radio galaxies and quasars to determine if their sky distribution is consistent with the standard $\Lambda$CDM model of cosmology. This model is based on the cosmological principle, which…

宇宙学与河外天体物理 · 物理学 2022-09-29 Nathan Secrest , Sebastian von Hausegger , Mohamed Rameez , Roya Mohayaee , Subir Sarkar

One of the major predictions of inflation is the existence of a stochastic background of cosmological gravitational waves (GW). These gravitational waves can induce significant temperature anisotropies in the Cosmic Microwave Background…

天体物理学 · 物理学 2009-11-07 Alessandro Melchiorri , Carolina Odman

The motion of the solar system barycenter with respect to the cosmic microwave background (CMB) induces a very large apparent dipole component into the CMB brightness map at the 3 mK level. In this Letter we discuss another kinematic effect…

天体物理学 · 物理学 2009-11-11 Scott Burles , Saul Rappaport

Anomalies in the cosmic microwave background (CMB) refer to features that have been observed, mostly at large angular scales, and which show some tension with the statistical predictions of the standard $\Lambda$CDM model. In this work, we…

广义相对论与量子宇宙学 · 物理学 2021-05-28 Ivan Agullo , Dimitrios Kranas , V. Sreenath

The large-angular-scale falloff in the autocorrelation function for the cosmic microwave background (CMB) temperature has long intrigued cosmologists and fueled speculation about suppressed superhorizon power. Here we highlight an…

宇宙学与河外天体物理 · 物理学 2023-11-13 Jahmour J. Givans , Marc Kamionkowski

The CMB angular temperature fluctuations observed by COBE and WMAP enable us to place a lower limit on the spectral distortions of the CMB at any angular scale. These distortions are connected with the simple fact, that the superposition of…

天体物理学 · 物理学 2009-11-10 J. Chluba , R. A. Sunyaev

Scattering of the temperature anisotropy quadrupole by free electrons in galaxy clusters leads to a secondary polarization signal in the cosmic microwave background (CMB) fluctuations. At low redshifts, the temperature quadrupole contains a…

天体物理学 · 物理学 2015-06-24 Daniel Baumann , Asantha Cooray

We explore the hemispherical asymmetry predicted in cosmic microwave background polarization when there is an asymmetry in temperature anisotropies due to primordial perturbations. We consider the cases of asymmetries due to adiabatic and…

宇宙学与河外天体物理 · 物理学 2015-05-20 M. H. Namjoo , A. A. Abolhasani , H. Assadullahi , S. Baghram , H. Firouzjahi , D. Wands

We present an in depth discussion of the production of gravitational waves from an inflationary phase that could have occurred in the early universe, giving derivations for the resulting spectrum and energy density. We also consider the…

高能物理 - 唯象学 · 物理学 2016-09-01 Martin White

The presence of a dipolar statistical anisotropy in the spectrum of cosmic microwave background (CMB) fluctuations was reported by the Wilkinson Microwave Anisotropy Probe (WMAP), and has recently been confirmed in the Planck 2013 analysis…

宇宙学与河外天体物理 · 物理学 2014-04-29 Sugumi Kanno , Misao Sasaki , Takahiro Tanaka