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The 21cm Signature of a Cosmic String Loop
Cosmology and Nongalactic Astrophysics · Submitted 27 Jan 2012
abstract compiled · 2026-09-23 · no language-model review
The authors' main claim These signals should be detectable in upcoming high redshift 21cm surveys.
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The abstract, sentence by sentence
Cosmic string loops lead to nonlinear baryon overdensities at early times, even before the time which in the standard LCDM model corresponds to the time of reionization. These overdense structures lead to signals in 21cm redshift surveys at large redshifts. In this paper, we calculate the amplitude and shape of the string loop-induced 21cm brightness temperature. We find that a string loop leads to a roughly elliptical region in redshift space with extra 21cm emission. The excess brightness temperature for strings with a tension close to the current upper bound can be as high as 1 degree K for string loops generated at early cosmological times (times comparable to the time of equal matter and radiation) and observed at a redshift of z + 1 = 30. The angular extent of these predicted "bright spots" is of the order 0.1 degree for a value of the string tension equal to the current upper bound. These signals should be detectable in upcoming high redshift 21cm surveys.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | Cosmic string loops lead to nonlinear baryon overdensities at early times, even before the time which in the standard LCDM model corresponds to the time of reionization. | background 0.77 | 0.15 | 0.06 | asserted 1.00 |
| s1 | These overdense structures lead to signals in 21cm redshift surveys at large redshifts. | background 0.69 | 0.14 | 0.07 | asserted 1.00 |
| s2 | In this paper, we calculate the amplitude and shape of the string loop-induced 21cm brightness temperature. | contribution 0.99 | 0.94 | 0.06 | asserted 0.91 |
| s3 | We find that a string loop leads to a roughly elliptical region in redshift space with extra 21cm emission. | result 1.00 | 0.96 | 0.39 | asserted 1.00 |
| s4 | The excess brightness temperature for strings with a tension close to the current upper bound can be as high as 1 degree K for string loops generated at early cosmological times (times comparable to the time of equal matter and radiation) and observed at a redshift of z + 1 = 30. | result 1.00 | 0.92 | 0.40 | asserted 0.54 |
| s5 | The angular extent of these predicted "bright spots" is of the order 0.1 degree for a value of the string tension equal to the current upper bound. | result 1.00 | 0.86 | 0.08 | asserted 0.99 |
| s6 | These signals should be detectable in upcoming high redshift 21cm surveys. | interpretation 0.96 | 0.28 | 0.32 | hedged possibility 0.65 |
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The paper
Original abstract
Cosmic string loops lead to nonlinear baryon overdensities at early times, even before the time which in the standard LCDM model corresponds to the time of reionization. These overdense structures lead to signals in 21cm redshift surveys at large redshifts. In this paper, we calculate the amplitude and shape of the string loop-induced 21cm brightness temperature. We find that a string loop leads to a roughly elliptical region in redshift space with extra 21cm emission. The excess brightness temperature for strings with a tension close to the current upper bound can be as high as 1 degree K for string loops generated at early cosmological times (times comparable to the time of equal matter and radiation) and observed at a redshift of z + 1 = 30. The angular extent of these predicted "bright spots" is of the order 0.1 degree for a value of the string tension equal to the current upper bound. These signals should be detectable in upcoming high redshift 21cm surveys.
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References
How the literature uses it
14 arXiv papers cite this in 19 sentences
Papers citing it · 10 sentences without a confident label
Uses its method or tool 1 paper
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As a result, the intrinsic line profile broadened by the Hubble flow is [ref] [equation] We take into account only the largest effect between them.
21 cm Angular Spectrum of Cosmic String Loops · 21 cm signature from the accreted filament · 0.89
Compares with it 1 paper
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It is worth pointing out that our values are smaller than the ones in Ref. [ref] in which a loop produces the brightness temperature as high as 1 K for $G μ∼10^-7$.
21 cm Angular Spectrum of Cosmic String Loops · 21 cm signature from the accreted filament · 0.98
Cites it as background 5 papers
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Several papers have investigated redshifted 21 cm signatures from string wakes produced by long strings [ref] and filaments created by string loops [ref] .
High redshift signatures in the 21 cm forest due to cosmic string wakes · Introduction · 0.97
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The 21 cm signature due to a static loop have been studied in Ref. [ref] .
21 cm Angular Spectrum of Cosmic String Loops · Introduction · 0.83
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These include the anisotropy of the CMB temperature [ref] and B-mode plarization [ref] , gravitational waves [ref] , gravitational lensing [ref] , wakes in the 21cm maps [ref] , early structure formation [ref] , early reionization due to early structure formation [ref] , and formation of dark matter clumps [ref] .
Constraints on Superconducting Cosmic Strings from Early Reionization · Introduction · 0.94
What it cites · 25 sentences without a confident label
Compares with 1 paper
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Note that the dependence on $G μ$ cancels out between the column height and the line profile, as it did in the case of cosmic string wakes [ref] .
The 21 cm Signature of Cosmic String Wakes · Brightness Temperature · 0.99
Cites as background 3 papers
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As can be argued analytically (see [ref] for reviews), the scaling solution of the infinite strings is maintained by the process of interactions between segments of infinite strings producing loops.
Topological Defects and Structure Formation · Preliminaries · 0.87
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As can be argued analytically (see [ref] for reviews), the scaling solution of the infinite strings is maintained by the process of interactions between segments of infinite strings producing loops.
Cosmic strings · Preliminaries · 0.87
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If the gas temperature $T_K$ is higher than that of the microwave photons at the redshift $z$ when our past light cone intersects the cloud, the signal will be in emission, if $T_K < T_γ$ it will be in absorption [For a detailed review article on the cosmology with the 21cm line see [ref] .].
Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe · Preliminaries · 1.00
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