Radio Galaxy Zoo (RGZ) was one of the follow-ons to Galaxy Zoo,
specifically a Zooniverse project to classify
(by crowd-sourcing) the radiomorphology of radio galaxies, using both infrared and radio images.
From this, evidence was gathered regarding whether a classified
galaxy shows radio evidence of a supermassive black hole (SMBH),
i.e., signs of AGN activity.
In 2025, Radio Galaxy Zoo data release 1, a
catalog of RGZ classifications was published.
Though the crowd-source RGZ classification is currently in "retired" status,
projects continue using the RGZ classifications.
Results from a number of radio surveys
underwent the RGZ crowd-sourced classification.
The resulting classifications are of value in their own right,
but also have provided fodder for testing and
generating automated methods of radio galaxy classification.