Galactic Rings Revisited. I. CVRHS Classifications of 3962 Ringed
  Galaxies from the Galaxy Zoo 2 Database
  Rings are important and characteristic features of disc-shaped galaxies. This
paper is the first in a series which re-visits galactic rings with the goals of
further understanding the nature of the features and for examining their role
in the secular evolution of galaxy structure. The series begins with a new
sample of 3962 galaxies drawn from the Galaxy Zoo 2 citizen science database,
selected because zoo volunteers recognized a ring-shaped pattern in the
morphology as seen in Sloan Digital Sky Survey colour images. The galaxies are
classified within the framework of the Comprehensive de Vaucouleurs revised
Hubble-Sandage (CVRHS) system. It is found that zoo volunteers cued on the same
kinds of ring-like features that were recognized in the 1995 Catalogue of
Southern Ringed Galaxies (CSRG). This paper presents the full catalogue of
morphological classifications, comparisons with other sources of
classifications, and some histograms designed mainly to highlight the content
of the catalogue. The advantages of the sample are its large size and the
generally good quality of the images; the main disadvantage is the low physical
resolution which limits the detectability of linearly small rings such as
nuclear rings. The catalogue includes mainly inner and outer disc rings and
lenses. Cataclysmic ("encounter-driven") rings (such as ring and polar ring
galaxies) are recognized in less than 1\% of the sample.
