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Extra radiation injection after neutrino decoupling in the early Universe contributes to the effective number of neutrino species that can be constrained by the cosmic microwave background (CMB). However, any effective neutrino number…

宇宙学与河外天体物理 · 物理学 2025-10-07 Shao-Ping Li , Jens Chluba

Current constraints on energy injection in the form of energetic particles before the epoch of recombination using CMB spectral distortions assume that all energy goes into $y$ and $\mu$-type distortions. We revisit these constraints with…

宇宙学与河外天体物理 · 物理学 2019-07-04 Sandeep Kumar Acharya , Rishi Khatri

The decay of massive neutrinos to final states containing only invisible particles is poorly constrained experimentally. In this letter we describe the constraints that can be put on neutrino mass and lifetime using CMBR measurements. We…

天体物理学 · 物理学 2009-10-30 Steen Hannestad

The presence of neutrinos from Boron decay in the flux observed on Earth is attested by the observation of their energy spectrum. Possible distortions of the spectrum investigated in current detectors are often interpreted in terms of…

高能物理 - 唯象学 · 物理学 2009-10-31 R. Escribano , J. -M. Frere , A. Gevaert , D. Monderen

We investigate the effect of potentially large distortions of the relic neutrino spectra on cosmological observables. To that end, we consider a phenomenological model of "gray" spectral distributions, described by a single parameter, which…

高能物理 - 唯象学 · 物理学 2025-06-27 Gabriela Barenboim , Julien Froustey , Cyril Pitrou , Hector Sanchis

We investigate the radiative decay of the cosmic neutrino background, and its impact on the spectrum of the cosmic microwave background (CMB) that is known to be a nearly perfect black body. We derive exact formulae for the decay of a…

The damping of primordial perturbations at small scales gives rise to distortions of the cosmic microwave background (CMB). Here, the dependence of the distortion on the different types of cosmological initial conditions is explored,…

宇宙学与河外天体物理 · 物理学 2014-04-18 Jens Chluba , Daniel Grin

We investigate in detail the possibility of constraining neutrino decays with data from the cosmic microwave background radiation (CMBR). Two generic decays are considered \nu_H -> \nu_L \phi and \nu_H -> \nu_L \nu_L_bar \nu_L. We have…

天体物理学 · 物理学 2009-10-31 Steen Hannestad

Departures of the Cosmic Microwave Background (CMB) frequency spectrum from a blackbody - commonly referred to as spectral distortions - encode information about the thermal history of the early Universe (redshift z < few x 10^6). While the…

宇宙学与河外天体物理 · 物理学 2015-06-16 Jens Chluba , Donghui Jeong

We calculate numerical solutions and analytic approximations for the intermediate-type spectral distortions. Detection of a \mu-type distortion (saturated comptonization) in the CMB will constrain the time of energy injection to be at a…

宇宙学与河外天体物理 · 物理学 2012-09-14 Rishi Khatri , Rashid A. Sunyaev

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

Spectral features in the CMB energy spectrum contain a wealth of information about the physical processes in the early Universe, z < 2 x 10^6. The CMB spectral distortions are complementary to all other probes of cosmology. In fact, most of…

宇宙学与河外天体物理 · 物理学 2013-06-12 Rashid A. Sunyaev , Rishi Khatri

Using simulation methods, distortion effects on energy spectra caused by errors in the energy determination have been investigated. For cosmic ray proton spectra, falling steeply with kinetic energy E as E-2.7, significant effects appear.…

天体物理学 · 物理学 2009-11-11 Per Carlson , Conny Wannemark

We study diffusion damping of acoustic waves in the photon-baryon fluid due to cosmic strings, and calculate the induced $\mu$- and $y$-type spectral distortions of the cosmic microwave background. For cosmic strings with tension within…

宇宙学与河外天体物理 · 物理学 2013-08-21 Hiroyuki Tashiro , Eray Sabancilar , Tanmay Vachaspati

Thomson scattering of CMBR temperature anisotropies will cause the spectrum of the CMBR to differ from blackbody even when one resolves all anisotropies. A formalism for computing the anisotropic and inhomogeneous spectral distortions of…

天体物理学 · 物理学 2007-05-23 Albert Stebbins

Global, symmetry-breaking phase transitions in the early universe can generate scaling seed networks which lead to metric perturbations. The acoustic waves in the photon-baryon plasma sourced by these metric perturbations, when Silk damped,…

宇宙学与河外天体物理 · 物理学 2014-11-05 Mustafa A. Amin , Daniel Grin

CMBR distortion concerned with recombination of the primordial plasma is calculated in frequency band from 1 GHz to 100 GHz in the frame of the standard cosmological model for different values of cosmological density parameters:…

天体物理学 · 物理学 2007-05-23 E. E. Kholupenko , A. V. Ivanchik , D. A. Varshalovich

Spectral distortions of the Cosmic Microwave Background (CMB) offer the possibility of probing processes which occurred during the evolution of our Universe going back up to Z$\simeq 10^7$. Unfortunately all the attempts so far carried out…

天体物理仪器与方法 · 物理学 2017-02-22 Giorgio Sironi

Spectral distortion of the cosmic microwave background provides a unique opportunity to probe primordial perturbations on very small scales by performing large-scale measurements. We discuss in a systematic and pedagogic way all the…

宇宙学与河外天体物理 · 物理学 2015-06-05 Enrico Pajer , Matias Zaldarriaga

It is shown that photon--photino inter-conversions (if exist) may result in a detectable CMBR spectrum distortion which amplitude depends on photino properties, such as its mass. An upper bound on the distortion parameter determined from…

天体物理学 · 物理学 2007-05-23 M. V. Medvedev
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