Gravitational Lens Images Generated by Cosmic Strings

Abstract

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...

Gravitational lensing by straight cosmic strings

“…which precisely coincides with (12). The approximate solution thus leads to the same answer as the exact solution.…”

Cosmic strings in $$f\left( R,L_m\right) $$ f R , L m gravity

“…Also these massive string solutions predict a much richer lensing behavior, as compared to the simple conical string model, leading to the possibility of a much wider range of deflection angles. Different aspects of lensing by cosmic strings have been analyzed in detail in the literature [168][169][170]. A potential lensing effect, which may provide some evidence for the existence of cosmic strings, comes from the CapodimonteSternberg lens candidate (CSL-1) [168].…”

Гравитационное Линзирование Прямыми Космическими Струнами

“…которая в точности совпадает с (12). Таким образом, приближенное решение приводит к точно такому же ответу, как и точное решение.…”