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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…

宇宙学与河外天体物理 · 物理学 2011-01-17 Pranjal Trivedi , Kandaswamy Subramanian , T. R. Seshadri

We present a detailed calculation of our previous short paper [M. Shiraishi, D. Nitta, S. Yokoyama, K. Ichiki, and K. Takahashi, Phys. Rev. D 82, 121302 (2010).] in which we have investigated a constraint on the magnetic field strength…

宇宙学与河外天体物理 · 物理学 2015-03-18 Maresuke Shiraishi , Daisuke Nitta , Shuichiro Yokoyama , Kiyotomo Ichiki , Keitaro Takahashi

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…

宇宙学与河外天体物理 · 物理学 2009-09-03 T. R. Seshadri , Kandaswamy Subramanian

If the seed magnetic fields exist in the early Universe, tensor components of their anisotropic stresses are not compensated prior to neutrino decoupling and the tensor metric perturbations generated from them survive passively.…

宇宙学与河外天体物理 · 物理学 2011-06-10 Maresuke Shiraishi , Daisuke Nitta , Shuichiro Yokoyama , Kiyotomo Ichiki , Keitaro Takahashi

We evaluate the angular bispectrum of the CMB temperature anisotropy at large angular scale due to a stochastic background of primordial magnetic fields. The shape of non-Gaussianity depends on the spectral index of the magnetic field power…

宇宙学与河外天体物理 · 物理学 2009-10-02 Chiara Caprini , Fabio Finelli , Daniela Paoletti , Antonio Riotto

We calculate the cosmic microwave background bispectrum of vector modes induced from primordial magnetic fields. We take into account the full angular dependence of the bispectrum and discuss the amplitude and also the shape of the…

宇宙学与河外天体物理 · 物理学 2011-02-25 Maresuke Shiraishi , Daisuke Nitta , Shuichiro Yokoyama , Kiyotomo Ichiki , Keitaro Takahashi

Primordial magnetic fields will generate non-Gaussian signals in the cosmic microwave background (CMB) as magnetic stresses and the temperature anisotropy they induce depend quadratically on the magnetic field. We compute a new measure of…

宇宙学与河外天体物理 · 物理学 2012-06-15 Pranjal Trivedi , T. R. Seshadri , Kandaswamy Subramanian

Cosmic magnetic fields are observed to be coherent on large scales and could have a primordial origin. Non-Gaussian signals in the cosmic microwave background (CMB) are generated by primordial magnetic fields as the magnetic stresses and…

宇宙学与河外天体物理 · 物理学 2014-03-05 Pranjal Trivedi , Kandaswamy Subramanian , T. R. Seshadri

We study the effect of primordial magnetic fields (PMFs) on the anisotropies of the cosmic microwave background (CMB). We assume the spectrum of PMFs is described by log-normal distribution which has a characteristic scale, rather than…

宇宙学与河外天体物理 · 物理学 2011-12-30 Dai G. Yamazaki , Kiyotomo Ichiki , Keitaro Takahashi

Oscillating shapes of the primordial bispectrum are present in many inflationary models. The Planck experiment has recently published measurements of oscillating shapes, which were however limited to the efficient frequency range of the…

宇宙学与河外天体物理 · 物理学 2016-08-22 M. Münchmeyer , F. Bouchet , M. Jackson , B. Wandelt

In this work we investigate the effects of the primordial magnetic fields on cosmic microwave background anisotropies (CMB). Based on cosmological magnetohydrodynamic (MHD) simulations we calculate the CMB anisotropy spectra and…

天体物理学 · 物理学 2009-11-13 Hiroyuki Tashiro , Naoshi Sugiyama , Robi Banerjee

We investigate bounds on the strength of the primordial magnetic field (PMF) from the cosmic microwave background (CMB) bispectra of the intensity (temperature) modes induced from the auto- and cross-correlated bispectra of the scalar and…

宇宙学与河外天体物理 · 物理学 2012-04-02 Maresuke Shiraishi , Daisuke Nitta , Shuichiro Yokoyama , Kiyotomo Ichiki

If the primordial fluctuations are non-Gaussian, then this non-Gaussianity will be apparent in the cosmic microwave background (CMB) sky. With their sensitive all-sky observation, MAP and Planck satellites should be able to detect weak…

天体物理学 · 物理学 2009-07-09 Eiichiro Komatsu , David N. Spergel

We investigate the power spectrum of the distortion of Cosmic Microwave Background (CMB) due to the decay of the primordial magnetic fields. It is known that there are two-types of the CMB distortions, so-called \mu- and y-types and we find…

宇宙学与河外天体物理 · 物理学 2014-03-12 Koichi Miyamoto , Toyokazu Sekiguchi , Hiroyuki Tashiro , Shuichiro Yokoyama

We constrain a stochastic background of primordial magnetic field (PMF) by its contribution to the angular power spectrum of cosmic microwave background anisotropies. We parametrize such stochastic background by a power-law spectrum with…

宇宙学与河外天体物理 · 物理学 2015-05-18 Daniela Paoletti , Fabio Finelli

Recent observations of the cosmic microwave background (CMB) have extended the measured power spectrum to higher multipoles $l\gtrsim$1000, and there appears to be possible evidence for excess power on small angular scales. The primordial…

天体物理学 · 物理学 2009-02-19 D. Yamazaki , K. Ichiki , T. Kajino , G. J. Mathews

We study the impact of a stochastic background of primordial magnetic fields on the scalar contribution of CMB anisotropies and on the matter power spectrum. We give the correct initial conditions for cosmological perturbations and the…

天体物理学 · 物理学 2008-12-18 Fabio Finelli , Francesco Paci , Daniela Paoletti

We present an all-sky formalism for the Cosmic Microwave Background (CMB) bispectrum induced by the primordial non-Gaussianities not only in scalar but also in vector and tensor fluctuations. We find that the bispectrum can be formed in an…

宇宙学与河外天体物理 · 物理学 2015-03-17 Maresuke Shiraishi , Daisuke Nitta , Shuichiro Yokoyama , Kiyotomo Ichiki , Keitaro Takahashi

An inhomogeneous cosmological magnetic field creates vortical perturbations that survive Silk damping on much smaller scales than compressional modes. This ensures that there is no sharp cut-off in anisotropy on arc-minute scales. As we had…

天体物理学 · 物理学 2009-11-07 Kandaswamy Subramanian , John D. Barrow

The cosmological magnetic field is one of the important physical quantities which affect strongly the cosmic microwave background (CMB) power spectrum. Recent CMB observations have been extended to higher multipoles $l\gtrsim$1000, and they…

天体物理学 · 物理学 2009-11-10 D. G. Yamazaki , K. Ichiki , T. Kajino
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