21 cm Angular Spectrum of Cosmic String Loops

Hiroyuki Tashiro

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21 cm Angular Spectrum of Cosmic String Loops

Hiroyuki Tashiro

Cosmology and Nongalactic Astrophysics · Submitted 21 May 2013

abstract compiled · 2026-09-23 · no language-model review

The authors' main claim We find that the angular power spectrum for $G\mu>10^{-8}$ at $z=30$ or $G\mu>10^{-10}$ at $z=20$ can dominate the spectrum of the primordial density fluctuations.

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Compiled by classifier-1.13-20260917 via OpenRouter, question bank abstract-p1-20260923, 2026-09-23: 1 request, 5,509 input tokens, $0.0002 reported.

What the abstract itself states, as probabilities: claims first 0.03 · states limitation 0.15 · human participants 0.01 · controlled comparison 0.14 · randomized assignment 0.01 · states quantitative result 0.99 · compares with prior results 0.64 · mentions code or data availability 0.02.

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The 21 cm signatures induced by moving cosmic string loops are investigated. Moving cosmic string loops seed filamentary nonlinear objects. We analytically evaluate the differential 21 cm brightness temperature from these objects. We show that the brightness temperature reaches 200 mK for a loop whose tension is about the current upper limit, $G\mu\sim10^{-7}$. We also calculate the angular power spectrum, assuming scaling in loop distribution. We find that the angular power spectrum for $G\mu>10^{-8}$ at $z=30$ or $G\mu>10^{-10}$ at $z=20$ can dominate the spectrum of the primordial density fluctuations. Finally we show that a future SKA-like observation has the potential to detect the power spectrum due to loops with $G\mu=10^{-8}$ at $z=20$.

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What the classifier reports for each sentence. The number is the probability it gave the label.
#	sentence	role	the authors' own work	states the main conclusion	strength
s0	The 21 cm signatures induced by moving cosmic string loops are investigated.	contribution 0.89	0.71	0.04	asserted 0.64
s1	Moving cosmic string loops seed filamentary nonlinear objects.	result 0.46	0.30	0.06	asserted 1.00
s2	We analytically evaluate the differential 21 cm brightness temperature from these objects.	method 0.78	0.95	0.05	asserted 0.97
s3	We show that the brightness temperature reaches 200 mK for a loop whose tension is about the current upper limit, $G\mu\sim10^{-7}$.	result 1.00	0.92	0.19	asserted 1.00
s4	We also calculate the angular power spectrum, assuming scaling in loop distribution.	method 0.75	0.94	0.06	asserted 0.82
s5	We find that the angular power spectrum for $G\mu>10^{-8}$ at $z=30$ or $G\mu>10^{-10}$ at $z=20$ can dominate the spectrum of the primordial density fluctuations.	result 0.99	0.94	0.52	asserted 0.99
s6	Finally we show that a future SKA-like observation has the potential to detect the power spectrum due to loops with $G\mu=10^{-8}$ at $z=20$.	result 0.51	0.88	0.30	hedged possibility 0.87

What kind of paper the classifier reports this is: theoretical result 1.00 · evidence from proof or derivation 0.99.

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Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

The paper

Original abstract

The 21 cm signatures induced by moving cosmic string loops are investigated. Moving cosmic string loops seed filamentary nonlinear objects. We analytically evaluate the differential 21 cm brightness temperature from these objects. We show that the brightness temperature reaches 200 mK for a loop whose tension is about the current upper limit, $G\mu\sim10^{-7}$. We also calculate the angular power spectrum, assuming scaling in loop distribution. We find that the angular power spectrum for $G\mu>10^{-8}$ at $z=30$ or $G\mu>10^{-10}$ at $z=20$ can dominate the spectrum of the primordial density fluctuations. Finally we show that a future SKA-like observation has the potential to detect the power spectrum due to loops with $G\mu=10^{-8}$ at $z=20$.

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References

How the literature uses it

3 arXiv papers cite this in 3 sentences

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

Papers citing it · 2 sentences without a confident label

Cites it as background 1 paper

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

What it cites · 9 sentences without a confident label

Uses the method or tool of 5 papers

We also calculate the angular power spectrum, assuming scaling in loop distribution [ref] .

Scaling of cosmic string loops · Introduction · 0.81
We also calculate the angular power spectrum, assuming scaling in loop distribution [ref] .

Cosmological evolution of cosmic string loops · Introduction · 0.81
We also calculate the angular power spectrum, assuming scaling in loop distribution [ref] .

Cosmic string loops in the expanding universe · Introduction · 0.81

Uses data or values from 3 papers

Throughout this paper, we take the values, $α=0.1$ and $v_i = 0.3$, suggested by simulations [ref] .

Large parallel cosmic string simulations: New results on loop production · accretion onto a moving loop · 0.99
WMAP and SPT data provide the limit $Gμ<1.7 ×10^-7$ [ref] .

Cosmic String constraints from WMAP and the South Pole Telescope · Introduction · 0.98
Recently Planck data updated the limit to $Gμ<1.5 ×10^-7$ [ref] .

Planck 2013 results. XXV. Searches for cosmic strings and other topological defects · Introduction · 0.92

Compares with 2 papers

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 $G μ∼10^-7$.

The 21cm Signature of a Cosmic String Loop · 21 cm signature from the accreted filament · 0.98
We found that the amplitude of the spectrum due to the loops is larger than the one due to long strings evaluated in Ref. [ref] .

Angular 21 cm Power Spectrum of a Scaling Distribution of Cosmic String Wakes · conclusion · 1.00

Cites as background 23 papers

The angular 21 cm power spectrum due to string wakes has also been investigated in Ref. [ref] .

Angular 21 cm Power Spectrum of a Scaling Distribution of Cosmic String Wakes · Introduction · 0.81
The 21 cm signature due to a static loop have been studied in Ref. [ref] .

The 21cm Signature of a Cosmic String Loop · Introduction · 0.83
Cosmological 21 cm signatures due to cosmic strings have been investigated in several papers [ref] .

Cosmic (super)string constraints from 21 cm radiation · Introduction · 0.96

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