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Magnetized CMB observables: a dedicated numerical approach
Astrophysics · Submitted 20 Dec 2007
abstract compiled · 2026-09-23 · no language-model review
The authors' main claim The temperature and polarization observables are exploited to infer the peculiar signatures of a pre-equality magnetic field.
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The paper's own sentences, arranged. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.
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The abstract, sentence by sentence
Large-scale magnetic fields affect the scalar modes of the geometry whose ultimate effect is to determine the anisotropies of the Cosmic Microwave Background (CMB in what follows). For the first time, a consistent numerical approach to the magnetized CMB anisotropies is pursued with the aim of assessing the angular power spectra of temperature and polarization when the scalar modes of the geometry and a stochastic background of inhomogeneous magnetic fields are simultaneously present in the plasma. The effects related to the magnetized nature of the plasma are taken into account both at the level of the dynamical equations and at the level of the initial conditions of the Einstein-Boltzmann hierarchy. The temperature and polarization observables are exploited to infer the peculiar signatures of a pre-equality magnetic field. Using the extrapolated best fit to the three year WMAP data the increase and distortions of the first seven peaks in the TT autocorrelations are monitored for different values of the regularized magnetic field intensity and for the physical range of spectral indices. Similar analyses are also conducted for the first few anticorrelation (and corrrelation) peaks of the TE power spectra. Possible interesting degeneracies and stimulating perspectives are pointed out and explored.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | Large-scale magnetic fields affect the scalar modes of the geometry whose ultimate effect is to determine the anisotropies of the Cosmic Microwave Background (CMB in what follows). | background 1.00 | 0.07 | 0.05 | asserted 1.00 |
| s1 | For the first time, a consistent numerical approach to the magnetized CMB anisotropies is pursued with the aim of assessing the angular power spectra of temperature and polarization when the scalar modes of the geometry and a stochastic background of inhomogeneous magnetic fields are simultaneously present in the plasma. | contribution 1.00 | 0.93 | 0.11 | asserted 0.98 |
| s2 | The effects related to the magnetized nature of the plasma are taken into account both at the level of the dynamical equations and at the level of the initial conditions of the Einstein-Boltzmann hierarchy. | method 0.98 | 0.80 | 0.05 | asserted 0.99 |
| s3 | The temperature and polarization observables are exploited to infer the peculiar signatures of a pre-equality magnetic field. | contribution 0.60 | 0.72 | 0.21 | asserted 0.93 |
| s4 | Using the extrapolated best fit to the three year WMAP data the increase and distortions of the first seven peaks in the TT autocorrelations are monitored for different values of the regularized magnetic field intensity and for the physical range of spectral indices. | method 0.74 | 0.92 | 0.12 | asserted 0.99 |
| s5 | Similar analyses are also conducted for the first few anticorrelation (and corrrelation) peaks of the TE power spectra. | contribution 0.68 | 0.90 | 0.04 | asserted 0.98 |
| s6 | Possible interesting degeneracies and stimulating perspectives are pointed out and explored. | interpretation 0.89 | 0.81 | 0.11 | hedged possibility 0.81 |
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The paper
Original abstract
Large-scale magnetic fields affect the scalar modes of the geometry whose ultimate effect is to determine the anisotropies of the Cosmic Microwave Background (CMB in what follows). For the first time, a consistent numerical approach to the magnetized CMB anisotropies is pursued with the aim of assessing the angular power spectra of temperature and polarization when the scalar modes of the geometry and a stochastic background of inhomogeneous magnetic fields are simultaneously present in the plasma. The effects related to the magnetized nature of the plasma are taken into account both at the level of the dynamical equations and at the level of the initial conditions of the Einstein-Boltzmann hierarchy. The temperature and polarization observables are exploited to infer the peculiar signatures of a pre-equality magnetic field. Using the extrapolated best fit to the three year WMAP data the increase and distortions of the first seven peaks in the TT autocorrelations are monitored for different values of the regularized magnetic field intensity and for the physical range of spectral indices. Similar analyses are also conducted for the first few anticorrelation (and corrrelation) peaks of the TE power spectra. Possible interesting degeneracies and stimulating perspectives are pointed out and explored.
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References
How the literature uses it
18 arXiv papers cite this in 30 sentences
Papers citing it · 19 sentences without a confident label
Contests it 1 paper
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Ref. [ref] uses the correct initial conditions, but a power spectrum for the PMF energy -density with a spectral index which is twice the one for the power spectrum of the magnetic field.
The Impact of Stochastic Primordial Magnetic Fields on the Scalar Contribution to Cosmic Microwave Background Anisotropies · Conclusions · contest 0.72
Builds on it 1 paper
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The remaining two points necessarily demand a full numerical integration which will be performed with the code devised in [ref] and hereby extended to handle initial data which are, simultaneously, magnetized and non-adiabatic.
Generalized CMB initial conditions with pre-equality magnetic fields · Pre-equality CMB initial conditions · 0.95
Compares with it 1 paper
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We have checked that the result reported in [ref] and ours [ref] agree.
The Impact of Stochastic Primordial Magnetic Fields on the Scalar Contribution to Cosmic Microwave Background Anisotropies · Initial Conditions · 0.99
Cites it as background 8 papers
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Before plunging into the discussion it is appropriate to recall [ref] that large-scale magnetic fields affect directly the Einstein equations since they contribute to the energy density, to the pressure and to the anisotropic stress: [equation] where $B^2 = B_iB^i$.
Generalized CMB initial conditions with pre-equality magnetic fields · Initial data of the Einstein-Boltzmann hierarchy · 0.87
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The effects of a stochastic primordial magnetic field on the CMB are many: spectral distortions of the monopole [ref] , the generation of scalar, vector and tensor perturbations in the metric affecting both the temperature and the polarization spectra, see e.g. [ref] , the production of non-Gaussian signatures leading to a non-zero temperature bispectrum and trispectrum, see e.g. [ref] , Faraday rotation of CMB polarization, see e.g. [ref] .
Magnetic fields from inflation: The CMB temperature anisotropies · Introduction · 1.00
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They considered anisotropic expansion [ref] , spectral $y$ and $μ$ distortions [ref] , anisotropies due to Alfven and slow magnetic waves [ref] , a changing ionization history due to plasma heating [ref] , extra polarization due to PMFs [ref] , as well as non-Gaussianity in bi- and tri-spectrum [ref] .
Cosmic Recombination in the Presence of Primordial Magnetic Fields · Introduction · 0.99
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