Problems and Methods of Modern Search for Cosmic Strings

In this paper, the theoretical and observational problems of the search for cosmic strings (CS) by methods of modern astrophysics are discussed and new possibilities for further observational search for CS are proposed and justified. In recent works by the authors, it was shown for the first time that taking into account the geometry of the CS (tilt and bend) cardinally affects one of the main observational methods of searching for CS: searching for chains of images of galaxies that should be formed due to the effect of gravitational lensing of background galaxies on the CS. Further, these theoretical developments were applied to the analysis of observational data of the double galaxy SDSS J110429.61+233150.3, previously found in the field of the assumed CS (CSc-1), identified, in turn, by the analysis of the CMB anisotropy. Based on these long-term studies, this paper for the first time identifies the fundamental problems of approximate theoretical models, within which the evolution of both CS networks and single CS is traditionally considered, and also for the first time justifies the rejection of the traditional search for extended chains of gravitational-lens pairs. In this paper, a new detailed strategy for searching for CS is proposed by identifying and analyzing the characteristic clustering of gravitationally lensed pairs. This strategy is demonstrated by the analysis of gravitationally lensed pairs in the CSc-1 region, and the requirements for future observations are indicated. Arguments are also given that admit a change in the linear density of CS in a wide range and that “heavy” CS do not contradict modern observational data, including that on the CMB anisotropy and the gravitational-wave background. A strategy for the systematic analysis of binary quasars (having a gravitationally lensed nature and an unidentified lensed object) as lensed on CS is discussed.