Cosmology and Nongalactic Astrophysics · arXiv:1403.2608 v2 · submitted 11 Mar 2014
21cm fluctuations from primordial magnetic fields
The paper says
“We find that the fluctuations of the 21cm line from the energy dissipation appear only on very small scales and those from the density fluctuations always dominate on observationally relevant angular scales.”
from the abstract · picked out as the main claim by a classifier
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The paper
Abstract
Recent observations of magnetic fields in intergalactic void regions and in high redshift galaxies may indicate that large scale magnetic fields have a primordial origin. If primordial magnetic fields were present soon after the recombination epoch, they would have induced density fluctuations on the one hand and dissipated their energy into the primordial gas on the other, and thereby significantly alter the thermal history of the Universe. Here we consider both the effects and calculate the brightness temperature fluctuations of the 21cm line using simple Monte Carlo simulations. We find that the fluctuations of the 21cm line from the energy dissipation appear only on very small scales and those from the density fluctuations always dominate on observationally relevant angular scales.
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. No sentence in this record was written by a model.
abstract compiled · 2026-09-23 · no language-model review
How the main claim is stated: asserted 1.00
What the abstract itself states, as probabilities: claims first 0.04 · states limitation 0.42 · human participants 0.01 · controlled comparison 0.05 · randomized assignment 0.01 · states quantitative result 0.08 · compares with prior results 0.09 · mentions code or data availability 0.02
The abstract, sentence by sentence
This table labels the abstract only (arXiv listing abstract v2). The number is the probability the classifier gave the label.
| Sentence | Role | The authors' own work | States the main conclusion | Strength |
|---|---|---|---|---|
| Recent observations of magnetic fields in intergalactic void regions and in high redshift galaxies may indicate that large scale magnetic fields have a primordial origin. | background 1.00 | 0.04 | 0.02 | hedged possibility 1.00 |
| If primordial magnetic fields were present soon after the recombination epoch, they would have induced density fluctuations on the one hand and dissipated their energy into the primordial gas on the other, and thereby significantly alter the thermal history of the Universe. | background 1.00 | 0.06 | 0.05 | hedged possibility 0.77 |
| Here we consider both the effects and calculate the brightness temperature fluctuations of the 21cm line using simple Monte Carlo simulations. | method 0.58 | 0.95 | 0.04 | asserted 0.78 |
| We find that the fluctuations of the 21cm line from the energy dissipation appear only on very small scales and those from the density fluctuations always dominate on observationally relevant angular scales. | result 1.00 | 0.96 | 0.89 | asserted 1.00 |
What kind of paper the classifier reports this is: simulation study 1.00 · evidence from simulation or computation 1.00
What was examined, and what was not
Sources read
- arXiv listing abstract v2
Not examined
- full text
- figures and tables
- references and citing sentences
- relations to other papers
Levels run
- P abstract
Not run
- S sections
- T body sentences
- C citations
- R cross-paper relations
How the labels were made
Compiled by classifier-1.13-20260917 via OpenRouter, question bank abstract-p1-20260923, 2026-09-23: 1 request, 3,665 input tokens, $0.0002 reported.
Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. This record as JSON
Cited by 3 Pith papers
Reviewed papers on Pith that cite this one. The full citation record
- Non-Gaussian matter fluctuations from primordial magnetic fields and galaxy luminosity function astro-ph.CO · Nov 2026
- Impact of Primordial Magnetic Field-induced Small-scale Power on Non-linear Structure Formation and Cosmic Reionization astro-ph.CO · Nov 2026
- The Effects of Dark Matter-Baryon Scattering on Redshifted 21 cm Signals astro-ph.CO · Aug 2014
How the literature uses it
6 arXiv papers cite this in 6 sentences
Papers citing it · 2 sentences without a confident label
Cites it as background 4 papers
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Many authors have discussed the observational constraints on PMFs from the Thomson optical depth [ref] , 21 cm anisotropies [ref] , cosmic shear [ref] , and galaxy surveys [ref] .
Thermal Sunyaev-Zel'dovich effect in the intergalactic medium with primordial magnetic fields · Introduction · 0.96
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This exciting signal has the potential to expand our knowledge on the formation mechanism of the first galaxies [ref] , the thermal history of the intergalactic medium (IGM) [ref] , the epoch of reionization [ref] , physics beyond the standard model [ref] , and possibly shed some light on the nature of dark matter [ref] .
Does it matter? A more careful treatment of density fluctuations in 21-cm simulations · Introduction · 0.88
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There have been related paper s investigating the 21 cm signal due to energy injection during the dark ages including the dissipation of magnetic fields [ref] , energy injection from primordial black holes [ref] , and the decay or annihilation of dark matter [ref] .
The Effects of Dark Matter-Baryon Scattering on Redshifted 21 cm Signals · Introduction · 0.97
What it cites · 9 sentences without a confident label
Uses data or values from 2 papers
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For these coefficients and $C$, we refer to Refs. [ref] .
A New Calculation of the Recombination Epoch · Temperature and ionization evolution of IGM gas · 0.87
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For these coefficients and $C$, we refer to Refs. [ref] .
How exactly did the Universe become neutral? · Temperature and ionization evolution of IGM gas · 0.87
Cites as background 10 papers
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This process is the so-called ambipolar diffusion [ref] and can happen at the late-time Universe in the dark age under the presence of electrically neutral particles [ref] .
Primordial Magnetic Fields in the Post-recombination Era and Early Reionization · Theory of ambipolar diffusion in the dark age · 0.95
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In particular, Refs. [ref] have investigated these global effect on the 21cm signals.
Probing Primordial Magnetic Fields with the 21cm Fluctuations · Introduction · 0.87
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The global effects of the heating from primordial magnetic fields have already been studied in Refs. [ref] .
The early reionization with the primordial magnetic fields · Introduction · 0.95
Challenges and discussion
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