Optical analysis of a CMB cosmic string candidate
  The complexity of the cosmological scenario regarding cosmic strings (CSs)
stands still in the way of a complete understanding. We describe here a
promising strategy for the possible detection of these elusive physical
entities. It is based on the search of strong gravitational lensing events in
the location area of the CS candidate (CSc-1), which was declared in a previous
work by CMB analysis. Using photometric and geometric criteria, we identified
pairs of candidates of lensed galaxies (LGCs) in the "string field" (SF), which
were then compared with the average density of background galaxy pairs in a set
of "control fields" (CFs). We found an excess of $22\%$ (per sq. deg.) of the
LGCs in SF, which exceeds the estimated cosmic dispersion. We also found that
the number of LGCs is in excess of $29.2\%$ in the angular separation bin
$[8'', 9'']$. Finally, we analysed the possibility of a preferred orientation
of the line connecting the centres of the LGCs. The orientation is
statistically significant for an angular separation bin $[4'',6'']$. Therefore,
we found two "windows" for the preferred angular separation for LGCs along the
possible CS. However, the confirmation of the gravitational lensing origin of
our LGCs requires spectroscopic observations which seem to be justified by the
present results. We plan to acquire their spectra as well as to continue the
study of the spectral and morphological features of the LGCs in the CSc-1 field
and to analyse the other CS-candidates using the same strategy.
