  Polar-ring galaxies are photometrically and kinematically decoupled systems
which are highly inclined to the major axis of the host galaxy. These objects
have been explored since the 1970s, but the rarity of these systems has made
such study difficult. We examine a sample of over 18,362 galaxies from the
Sloan Digital Sky Survey (SDSS) Stripe 82 for the presence of galaxies with
polar structures. Using deep SDSS Stripe 82, DESI Legacy Imaging Surveys, and
Hyper Suprime-Cam Subaru Strategic Program, we select 53 good candidate
galaxies with photometrically decoupled polar rings, 9 galaxies with polar
halos, and 34 possibly forming polar-ring galaxies, versus 13 polar-ring
candidates previously mentioned in the literature for the Stripe 82. Our
results suggest that the occurrence rate of galaxies with polar structures may
be significantly underestimated, as revealed by the deep observations, and may
amount to 1-3% of non-dwarf galaxies.

Astrophysics of Galaxies