Type-I cosmic-string network

Hiramatsu, Takashi; Sendouda, Yuuiti; Takahashi, Keitaro; Yamauchi, Daisuke; Yoo, Chul Moon

doi:10.1103/physrevd.88.085021

Cited by 25 publications

(34 citation statements)

References 75 publications

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“…Images from the PanSTARRS survey were used for template subtraction, and stars from this catalogue for calibration. Both sources are clearly detected, and the derived magnitudes are comparable to those derived by other teams (Tan et al 2019;Hiramatsu et al 2019;Bhalerao et al 2019;Burke et al 2019;Kilpatrick et al 2019;Castro-Tirado et al 2019;Sun et al 2019). However, both events were ruled out as a possible counterpart, as they were spectroscopically identified as type II SNe (Pavana et al 2019;Perley et al 2019;Buckley et al 2019;Izzo et al 2019;Wiersema et al 2019;Nicholl et al 2019a;Castro-Tirado et al 2019;Dichiara et al 2019;Chang et al 2019).…”

Section: External Counterpart Candidates Found By Ztf and Swift Uvotsupporting

confidence: 86%

The first six months of the Advanced LIGO’s and Advanced Virgo’s third observing run with GRANDMA

Antier

Agayeva

Aivazyan

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We present the Global Rapid Advanced Network Devoted to the Multi-messenger Addicts (GRANDMA). The network consists of 21 telescopes with both photometric and spectroscopic facilities. They are connected together thanks to a dedicated infrastructure. The network aims at coordinating the observations of large sky position estimates of transient events to enhance their follow-up and reduce the delay between the initial detection and the optical confirmation. The GRANDMA program mainly focuses on follow-up of gravitational-wave alerts to find and characterise the electromagnetic counterpart during the third observational campaign of the Advanced LIGO and Advanced Virgo detectors. But it allows for any follow-up of transient alerts involving neutrinos or gamma-ray bursts, even with poor spatial localisation. We present the different facilities, tools, and methods we developed for this network, and show its efficiency using observations of LIGO/Virgo S190425z, a binary neutron star merger candidate. We furthermore report on all GRANDMA follow-up observations performed during the first six months of the LIGO-Virgo observational campaign, and we derive constraints on the kilonova properties assuming that the events' locations were imaged by our telescopes.

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Section: External Counterpart Candidates Found By Ztf and Swift Uvotsupporting

confidence: 86%

The first six months of the Advanced LIGO’s and Advanced Virgo’s third observing run with GRANDMA

Antier

Agayeva

Aivazyan

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…At the critical coupling, parallel straight strings in Minkowski space do not interact, whereas for β < 1 strings attract each other, and for β > 1 they repel. In the β < 1 case strings can form bound states due to their attraction, and the network scaling properties could be somewhat different from the β = 1 case, as pointed out in [36]. We will report on results of our simulations for β < 1 in a future publication.…”

Section: A Continuum Formulationmentioning

confidence: 83%

Scaling from gauge and scalar radiation in Abelian-Higgs string networks

et al. 2017

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We investigate cosmic string networks in the Abelian Higgs model using data from a campaign of large-scale numerical simulations on lattices of up to 4096 3 grid points. We observe scaling or selfsimilarity of the networks over a wide range of scales, and estimate the asymptotic values of the mean string separation in horizon length unitsξ and of the mean square string velocityv 2 in the continuum and large time limits. The scaling occurs because the strings lose energy into classical radiation of the scalar and gauge fields of the Abelian Higgs model. We quantify the energy loss with a dimensionless radiative efficiency parameter, and show that it does not vary significantly with lattice spacing or string separation. This implies that the radiative energy loss underlying the scaling behaviour is not a lattice artefact, and justifies the extrapolation of measured network properties to large times for computations of cosmological perturbations. We also show that the core growth method, which increases the defect core width with time to extend the dynamic range of simulations, does not introduce significant systematic error. We compareξ andv 2 to values measured in simulations using the Nambu-Goto approximation, finding that the latter underestimate the mean string separation by about 25%, and overestimatev 2 by about 10%. The scaling of the string separation implies that string loops decay by the emission of massive radiation within a Hubble time in field theory simulations, in contrast to the Nambu-Goto scenario which neglects this energy loss mechanism. String loops surviving for only one Hubble time emit much less gravitational radiation than in the Nambu-Goto scenario, and are consequently subject to much weaker gravitational wave constraints on their tension.

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“…Strings with Y-shaped junctions occur in many models, and have been the subject of numerous studies, from QCD [1], to cosmic strings [2][3][4][5][6][7][8][9], and cosmic superstrings [10][11][12][13]. In a cosmological context, the presence of Y-junctions on a string network can give rise to many interesting effects: for instance, the lensing pattern of a distant light source background sources can pick up a distinctive triplified aspect [14,15]; when kinks (discontinuities on the tangent vector of a string) travel through a junction they multiply (in number) thus potentially sourcing more gravitational waves [16,17]; and also networks of cosmic superstrings lead to novel effects on the CMB temperature and polarization spectra [18,19].…”

Section: Introductionmentioning

confidence: 99%

Y-junction intercommutations of current carrying strings

et al. 2018

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Under certain conditions the collision and intercommutation of two cosmic strings can result in the formation of a third string, with the three strings then remaining connected at Y-junctions. The kinematics and dynamics of collisions of this type have been the subject of analytical and numerical analyses in the special case in which the strings are Nambu-Goto. Cosmic strings, however, may well carry currents, in which case their dynamics is not given by the Nambu-Goto action. Our aim is to extend the kinematic analysis to more general kinds of string model. We focus in particular on the collision of strings described by conservative elastic string models, characteristic of current carrying strings, and which are expected to form in a cosmological context. As opposed to NambuGoto strings collisions, we show that in this case the collision cannot lead to the formation of a third elastic string: if dynamically such a string forms then the joining string must be described by a more general equation of state. This process will be studied numerically in a forthcoming publication.

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Type-I cosmic-string network

Cited by 25 publications

References 75 publications

The first six months of the Advanced LIGO’s and Advanced Virgo’s third observing run with GRANDMA

The first six months of the Advanced LIGO’s and Advanced Virgo’s third observing run with GRANDMA

Scaling from gauge and scalar radiation in Abelian-Higgs string networks

Y-junction intercommutations of current carrying strings

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