Quasar variability limits on cosmological density of cosmic strings

Tuntsov, Artem V.; Пширков, М. С.

doi:10.1103/physrevd.81.063523

Cited by 15 publications

(11 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, our masses are larger than those reported by pa-rameter fits to the CMB [7][8][9][10] as well as gravitational wave searches [12,13]. The recent microlensing search carried out on SDSS quasars [16] is sensitive to very lowmass strings, but reports a similar sensitivity for Ω strings . Our direct searches may be sensitive to a particular class of strings that could be missed by other searches.…”

Section: Discussioncontrasting

confidence: 50%

Search for cosmic strings in the COSMOS survey

et al. 2011

View full text Add to dashboard Cite

We search the COSMOS survey for pairs of galaxies consistent with the gravitational lensing signature of a cosmic string. The COSMOS survey imaged 1.64 square degrees using the Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope (HST). Our technique includes estimates of the efficiency for finding the lensed galaxy pair. We find no evidence for cosmic strings with a mass per unit length of Gµ/c 2 < 3.0 × 10 −7 out to redshifts greater than 0.6 and set 95% upper limits. This corresponds to a global 95% upper limit of Ωstrings < 0.0028.

show abstract

Section: Discussioncontrasting

confidence: 50%

Search for cosmic strings in the COSMOS survey

et al. 2011

View full text Add to dashboard Cite

show abstract

“…For instance, since the universal loop distribution plotted in Fig. 2 is significantly different than the loop distributions used so far in the literature, various constraints on GU coming from gravitational wave emission, lensing or pulsar-timing should be re-examined [32,33,69,34,70]. All along the calculation, we have kept γ d and γ c as undetermined parameters (apart from the numerical examples) since these parameters may equally well be used to represent other physical effects.…”

Section: Discussionmentioning

confidence: 99%

Cosmic string loop distribution on all length scales and at any redshift

Lorenz¹,

Ringeval²,

Sakellariadou³

2010

J. Cosmol. Astropart. Phys.

142

209

View full text Add to dashboard Cite

We analytically derive the expected number density distribution of Nambu-Goto cosmic string loops at any redshift soon after the time of string formation to today. Our approach is based on the Polchinski-Rocha model of loop formation from long strings which we adjust to fit numerical simulations and complement by a phenomenological modelling of gravitational backreaction. Cosmological evolution drives the loop distribution towards scaling on all length scales in both the radiation and matter era. Memory of any reasonable initial loop distribution in the radiation era is shown to be erased well before Big Bang Nucleosynthesis. In the matter era, the loop distribution reaches full scaling, up to some residual loops from the radiation era which may be present for extremely low string tension. Finally, the number density of loops below the gravitational cutoff is shown to be scale independent, proportional to a negative power of the string tension and insensitive to the details of the backreaction modelling. As an application, we show that the energy density parameter of loops today cannot exceed 10 −5 for currently allowed string tension values, while the loop number density cannot be less than 10 −6 per Mpc 3 . Our result should provide a more robust basis for studying the cosmological consequences of cosmic string loops.PACS numbers: 98.80. Cq, 98.70.Vc Cosmic string loop distribution on all length scales and at any redshift 2

show abstract

“…For instance, the CMB analysis based on WMAP and the South Pole Telescope yields an upper bound on the string tension as Gµ < 1.7 × 10 −7 [38], and this constraint has been recently improved to be Gµ < 1.3×10 −7 with the help of the Planck data [39]. As cosmic strings can also lead to relic gravitational waves in the form of a stochastic background, a model-dependent constraint from the pulsar timing measurements on the string tension can be obtained in about the same order of the bound from CMB [40][41][42][43][44][45]. Further constraints on SCSs can be derived through the spectral distortions of the CMB photons [11][12][13], namely, the parameter region with 10 −19 < Gµ < 10 −7 and I > 10 4 GeV would be ruled out [46].…”

Section: Introductionmentioning

confidence: 99%

Superconducting cosmic strings as sources of cosmological fast radio bursts

Wang

Cai

2017

Eur. Phys. J. C

View full text Add to dashboard Cite

In this paper we calculate the radio burst signals from three kinds of structures of superconducting cosmic strings. By taking into account the observational factors including scattering and relativistic effects, we derive the event rate of radio bursts as a function of redshift with the theoretical parameters Gμ and I of superconducting strings. Our analyses show that cusps and kinks may have noticeable contributions to the event rate and in most cases cusps would dominate the contribution, while the kink-kink collisions tend to have secondary effects. By fitting theoretical predictions with the normalized data of fast radio bursts, we for the first time constrain the parameter space of superconducting strings and report that the parameter space of Gμ ∼ [10 −14 , 10 −12 ] and I ∼ [10 −1 , 10 2 ] GeV fit the observation well although the statistic significance is low due to the lack of observational data. Moreover, we derive two types of best fittings, with one being dominated by cusps with a redshift z = 1.3, and the other dominated by kinks at the range of the maximal event rate.

show abstract

Quasar variability limits on cosmological density of cosmic strings

Cited by 15 publications

References 49 publications

Search for cosmic strings in the COSMOS survey

Search for cosmic strings in the COSMOS survey

Cosmic string loop distribution on all length scales and at any redshift

Superconducting cosmic strings as sources of cosmological fast radio bursts

Contact Info

Product

Resources

About