Local constraints on cosmic string loops from photometry and pulsar timing

Пширков, М. С.; Tuntsov, Artem V.

doi:10.1103/physrevd.81.083519

Cited by 32 publications

(17 citation statements)

References 39 publications

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“…Eq. (18). However, it is not clear that this form of the ORF can be used in a selection of cases where the pulsars no longer lie at many radiation wavelengths from the SSB and/or from each other.…”

Section: Correlated Phase Changes From the Pulsar Termmentioning

confidence: 99%

“…A promising class of sources in this frequency band are supermassive black hole binary (SMBHB) systems with masses in the range of ∼10 7 -10 9 M ⊙ during their slow, adiabatic inspiral phase [9][10][11][12][13][14][15]. GWs from other more speculative sources from the early Universe, including cosmic strings [16][17][18] and relic GWs [19,20], are also expected to be found in this frequency band. Searches of increasing sensitivity are currently ongoing in the European PTA [21], the Parkes PTA [22], and the North American Nanohertz Gravitational Wave Observatory [23], which together form the International PTA (IPTA) [24].…”

Section: Introductionmentioning

confidence: 99%

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Effect of small interpulsar distances in stochastic gravitational wave background searches with pulsar timing arrays

Mingarelli

Sidery

2014

Phys. Rev. D

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One of the primary objectives for pulsar timing arrays (PTAs) is to detect a stochastic background generated by the incoherent superposition of gravitational waves (GWs), in particular from the cosmic population of supermassive black hole binaries. Current stochastic background searches assume that pulsars in a PTA are separated from each other and the Earth by many GW wavelengths. As more millisecond pulsars are discovered and added to PTAs, some may be separated by only a few radiation wavelengths or less, resulting in correlated GW phase changes between close pulsars in the array. Here we investigate how PTA overlap reduction functions (ORFs), up to quadrupole order, are affected by these additional correlated phase changes, and how they are in turn affected by relaxing the assumption that all pulsars are equidistant from the solar system barycenter. We find that in the low-frequency GW background limit of f ∼ 10 −9 Hz, and for pulsars at varying distances from the Earth, these additional correlations only affect the ORFs by a few percent for pulsar pairs at large angular separations, as expected. However, when nearby (order 100 pc) pulsars are separated by less than a few degrees, the correlated phase changes can introduce variations of a few tens of percent in the magnitude of the isotropic ORF, and much larger fractional differences in the anisotropic ORFs-up to 188 in the m ¼ 0, l ¼ 2 ORF for equidistant pulsars separated by 3°. In fact, the magnitude of most of the anisotropic ORFs is largest at small, but nonzero, pulsar separations. Finally, we write down a small angle approximation for the correlated phase changes which can easily be implemented in search pipelines, and for completeness, examine the behavior of the ORFs for pulsars which lie at a radiation wavelength from the Earth.

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Section: Correlated Phase Changes From the Pulsar Termmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of small interpulsar distances in stochastic gravitational wave background searches with pulsar timing arrays

Mingarelli

Sidery

2014

Phys. Rev. D

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“…Estimates can be made for any experiment which repeatedly measures the flux of stellar sources. The first string microlensing search [154] was recently completed using photometric data from space-based missions CoRoT 4 [155] and RXTE 5 [156]. The methodology was potentially capable of detecting strings with tensions 10 −16 < Gµ < 10…”

Section: Detection 81 Detection Via Microlensingmentioning

confidence: 99%

Inflation, string theory and cosmic strings

Chernoff

Tye

2015

Int. J. Mod. Phys. D

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At its very beginning, the universe is believed to have grown exponentially in size via the mechanism of inflation. The almost scale-invariant density perturbation spectrum predicted by inflation is strongly supported by cosmological observations, in particular the cosmic microwave background radiation. However, the universe's precise inflationary scenario remains a profound problem for cosmology and for fundamental physics. String theory, the most-studied theory as the final physical theory of nature, should provide an answer to this question. Some of the proposals on how inflation is realized in string theory are reviewed. Since everything is made of strings, some string loops of cosmological sizes are likely to survive in the hot big bang that followed inflation. They appear as cosmic strings, which can have intricate properties. Because of the warped geometry in flux compactification of the extra spatial dimensions in string theory, some of the cosmic strings may have tensions substantially below the Planck or string scale. Such strings cluster in a manner similar to dark matter leading to hugely enhanced densities. As a result, numerous fossil remnants of the low tension cosmic strings may exist within the galaxy. They can be revealed through the optical lensing of background stars in the near future and studied in detail through gravitational wave emission. We anticipate that these cosmic strings will permit us to address central questions about the properties of string theory as well as the birth of our universe.

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“…The signal received at the Earth is in fact a linear combination of the GW perturbation at the time when the GW transits at the pulsar, the so-called "pulsar term", and then when the GW passes the Earth, called the "Earth term". [2013]; Pshirkov and Tuntsov [2010]; Sanidas et al [2012] and relic GWs, see e.g. Zhao [2011], are also expected to be found in this frequency band.…”

Section: Introductionmentioning

confidence: 99%

Gravitational Wave Astrophysics with Pulsar Timing Arrays

Mingarelli

2016

Springer Theses

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Local constraints on cosmic string loops from photometry and pulsar timing

Cited by 32 publications

References 39 publications

Effect of small interpulsar distances in stochastic gravitational wave background searches with pulsar timing arrays

Effect of small interpulsar distances in stochastic gravitational wave background searches with pulsar timing arrays

Inflation, string theory and cosmic strings

Gravitational Wave Astrophysics with Pulsar Timing Arrays

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