21 cm angular spectrum of cosmic string loops

Tashiro, Hiroyuki

doi:10.1103/physrevd.87.123535

Cited by 4 publications

(6 citation statements)

References 95 publications

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“…[34] (for a more refined analysis accounting for the three-dimensional deviation of the charged particle, see Ref. [30]). The basic assumption is that the deflection experienced by the electron in the IGMF is in any case small.…”

Section: Stochastic Igmf and Deflection Anglementioning

confidence: 99%

Gamma-ray observations of blazars and the intergalactic magnetic field spectrum

Caprini

Gabici

2015

Phys. Rev. D

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9 pages, 5 figuresInternational audienceVery-high energy observations of blazars can be used to constrain the strength of the intergalactic magnetic field. A simplifying assumption which is often made is that of a magnetic field of constant strength composed by randomly oriented and identical cells. In this paper, we demonstrate that a more realistic description of the structure of the intergalactic magnetic field is indeed needed. If such a description is adopted, the observational bounds on the field strength are significantly affected in the limit of short field correlation lengths: in particular, they acquire a dependence on the magnetic field power spectrum. In the case of intergalactic magnetic fields which are generated causally, for which the magnetic field large scale spectral index is $n_B\geq 2$ and even, the observational lower bound becomes more constraining by about a factor 3. If instead $-3

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Section: Stochastic Igmf and Deflection Anglementioning

confidence: 99%

Gamma-ray observations of blazars and the intergalactic magnetic field spectrum

Caprini

Gabici

2015

Phys. Rev. D

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“…The ionization history of the universe is affected by loops through early star formation [21,22], which is seeded by the large, slow loops. Neutral hydrogen overdensities caused by loops [23,24] create bright spots in high-redshift 21cm surveys, and dark matter overdensities [25] have enhanced decay signatures. Microlensing of stars may occur from loops slow enough to be captured by galaxy halos, even for very low tensions [26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Number of cosmic string loops

2014

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Using recent simulation results, we provide the mass and speed spectrum of cosmic string loops. This is the quantity of primary interest for many phenomenological signatures of cosmic strings, and it can be accurately predicted using recently acquired detailed knowledge of the loop production function. We emphasize that gravitational smoothing of long strings does not play any role in determining the total number of existing loops. We derive a bound on the string tension imposed by recent constraints on the stochastic gravitational wave background from pulsar timing arrays, finding Gµ ≤ 2.8 × 10 −9 . We also provide a derivation of the Boltzmann equation for cosmic string loops in the language of differential forms.

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“…The subsequent self-gravitational contraction of such wakes will also draw in ordinary matter, possibly resulting in secondary shocks (Hernández & Brandenberger 2012) and various observational effect of the entrained hydrogen, e.g. the enhanced 21 cm emission (Tashiro 2013;Brandenberger et al 2013;Brandenberger 2014). As the wake gravitationally contracts, entrains and heats hydrogen, it no longer presents such a clear and welldefined angular shape.…”

Section: Discussionmentioning

confidence: 99%

“…So far, cosmic string wakes has been considered primarily in the collisionless medium where they produce the wedge-shaped wake with angle θ/2 and over-density of two, see, e.g. (Silk & Vilenkin 1984; Brandenberger et al 2010;Tashiro 2013;Brandenberger 2014). The gas will subsequently accrete on the dark matter to produce features in HI.…”

Section: Detection In the Early Universe By 21mentioning

confidence: 99%

“…(Silk & Vilenkin 1984; -Flow around a linear topological angle defect of θ. I am using Euclidean 2D plane with a dashed area representing an angular cut theta, which is parallel to the flow velocity. Brandenberger et al 2010;Tashiro 2013;Brandenberger 2014). The gas will subsequently accrete on the dark matter to produce features in HI.…”

Section: Detection In the Early Universe By 21mentioning

confidence: 99%

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The Flow Around a Cosmic String. I. Hydrodynamic Solution

Beresnyak

2015

ApJ

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Cosmic strings are linear topological defects which are hypothesized to be produced during inflation. Most searches for strings have been relying on the string's lensing of background galaxies or CMB. In this paper I derive a solution for the supersonic flow of the collisional gas past the cosmic string which has two planar shocks with shock compression ratio that depend on the angle defect of the string and its speed. The shocks result in compression and heating of the gas and, given favorable condition, particle acceleration. The gas heating and overdensity in an unusual wedge shape can be detected by observing HI line at high redshifts. The particle acceleration can occur in present-day Universe when the string crosses the hot gas contained in galaxy clusters and, since the consequences of such collision persist for cosmological timescales, could be located by looking at the unusual large-scale radio sources situated on a single spatial plane.

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21 cm angular spectrum of cosmic string loops

Cited by 4 publications

References 95 publications

Gamma-ray observations of blazars and the intergalactic magnetic field spectrum

Gamma-ray observations of blazars and the intergalactic magnetic field spectrum

Number of cosmic string loops

The Flow Around a Cosmic String. I. Hydrodynamic Solution

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