CSL-1: chance projection effect or serendipitous discovery of a gravitational lens induced by a cosmic string?

Cosmic strings in non-abelian gauge theories naturally gain a spectrum of massless, or light, excitations arising from their embedding in color and flavor space. This opens up the possibility that colliding strings miss each other in the internal space, reducing the probability of reconnection. We study the topology of the non-abelian vortex moduli space to determine the outcome of string collision. Surprisingly we find that the probability of classical reconnection in this system remains unity, with strings passing through each other only for finely tuned initial conditions. We proceed to show how this conclusion can be changed by symmetry breaking effects, or by quantum effects associated to fermionic zero modes, and present examples where the probability of reconnection in a U(N) gauge theory ranges from 1/N for low-energy collisions to one at higher energies.

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“…3 Generically the orbits of the SU (2) F action onM 2,2 are three dimensional. They degenerate to two dimensional orbits on M| U(1) and M| ω=0 .…”

Section: Two Submanifoldsmentioning

confidence: 99%

Reconnection of non-abelian cosmic strings

Hashimoto

Tong

2005

J. Cosmol. Astropart. Phys.

119

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“…Despite being a natural prediction of many cosmological theories, cosmic strings have not been observed yet [11][12][13], which raises an obvious question about the origin of this discrepancy. Attempts to answer it would benefit from an * e-mail: tyomich@sai.msu.ru † e-mail: pshirkov@prao.ru estimate of the actual density of stings in the real Universe or, in the absence of their detection, an upper limit on this parameter.…”

Section: Introductionmentioning

confidence: 99%

Quasar variability limits on cosmological density of cosmic strings

Tuntsov

Пширков

2010

Phys. Rev. D

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We put robust upper limits on the average cosmological density Ωs of cosmic strings based on the variability properties of a large homogeneous sample of SDSS quasars. We search for an excess of characteristic variations of quasar brightness that are associated with string lensing and use the observed distribution of this variation to constrain the density of strings. The limits obtained do not invoke any clustering of strings, apply to both open segments and closed loops of strings, usefully extend over a wide range of tensions 10 −13 < Gµ/c 2 < 10 −9 and reach down the level of Ωs = 0.01 and below. Further progress in this direction will depend on better understanding of quasar intrinsic variability rather than a mere increase in the volume of data.PACS numbers: 98.80. Cq, 98.54.Aj, 95.75.De,95.80.+p

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“…CSL o 3 8 57" , was discovered in the OACDF [21] by an international collaboration, [22]. CSL-1, is a double extended source laying in a low density field and with the two components separated by ~1.9 arcsec.…”

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confidence: 99%

“…The other possible explanation, that of a rare chance alignment of two identical giant ellipticals at the same redshift seemed very unlikely due to a series of odd circumstances: the two ellipticals should have been relatively near, = 11 kpc, each other, and in spite of this, undistorted, with identical (within the errors) spectra, and residing in a relatively low density environment (no other galaxies could be detected in the same region). Even though at the end it was proved that, in spite of all odds, this was the case [23], the detailed study of this anomalous object allowed to investigate in some detail another aspect of the expected observational effects induced by cosmic strings [13,17,22,24].…”

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confidence: 99%

Gravitational Lens Images Generated by Cosmic Strings

Sazhin¹,

Sazhina²,

Capaccioli³

et al. 2010

TOAAJ

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Abstract:In this review paper the current understanding on the properties of cosmic strings is shortly outlined with special emphasis on the observational signatures which can be expected both in the optical, through gravitational lensing, and in the radio, through anisotropies in the cosmic microwave background. The experience gathered during the long term investigation of the former candidate CSL-1 is also shortly summarized.Keywords: Cosmology, cosmic string, quasars, gravitational lensing, the CMBR anisotropy. COSMIC STRINGS: GENERALITIES AND THEIR ROLE IN PARTICLE PHYSICSThe topological defects of space-time known as cosmic strings were introduced in the late seventies by Kibble [1] and have been extensively discussed over the past decades by several authors [2,3].Their existence finds support in a large class of early Universe models based on the superstring theory [4][5][6]. Cosmic strings are in fact predicted by compactification models, in theories with extended additional dimensions, and are easily justified within the current inflationary scenarios. It is important to stress that in comparision with other topological defects such as monopoles, domain walls, textures, etc., cosmic strings are the most likely to exist.Nowadays, inflation finds a widespread consensus within the cosmological community and is in good agreement with observational astronomical data. On the other end, the braneantibrane inflationary mechanism is the most natural model arising from superstring theories (being one of the most promising to achieve a full description of the Universe at Planckian time-scales) theory tells us that, within this mechanism, inflation ends when the brane and the antibrane annihilate. This process is likely to generate an extremely rich spectrum of post-inflationary remnants. Cosmic strings are among the most likely remnants with a rather rich spectrum.Without any doubt, the discovery of any of such objects would lead to a quantum leap in many fields of fundamental physics and, more specifically, in understanding the rules of GUT and the processes occurring in the pre-inflationary Universe. The linear density of a string (or its tension) *Address correspondence to this author at the Sternberg Astronomical Institute, Moscow State University, University pr. 13, Moscow, Russia; Tel: +7 495 939 50 06; Fax: +7 495 932 88 41; E-mail: miksazhin@yandex.ru depends in fact on the symmetry breaking scale. The specific equation which links these two values depends both on the model of phase transition and on the specific form of the scalar field potential. In the case of a global U(1) string (i.e. the simplest case with winding number n = 1), the equation is, [7]:where vac is the energy density of the false vacuum and H is the Compton wavelenght of the Higgs boson. Here μ has dimension of linear density.The most relevant and, what is more important, model independent feature of cosmic strings is that they are one dimensional objects with diameter of the order of Planckian size of 10 33 cm. The microscopic charact...

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CSL-1: chance projection effect or serendipitous discovery of a gravitational lens induced by a cosmic string?

Cited by 106 publications

References 14 publications

Reconnection of non-abelian cosmic strings

Reconnection of non-abelian cosmic strings

Quasar variability limits on cosmological density of cosmic strings

Gravitational Lens Images Generated by Cosmic Strings

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