Welcome to Overlap Zoo! Please read the tutorial carefully before you begin classifying!
FAQ
How did the project start?
This project began as an undergraduate research project inspired by the work of Keel 2013. It started as a private internal beta test with a small research group and some additional volunteers, but it has now become a full-scale citizen science project! If you want to see the results of the internal beta test, please see Butrum 2026.
When will the project end?
The plan is to keep this project going for as long as we can. We would like to identify as many overlapping galaxy pairs as possible, so as long as techniques for finding these systems continue to improve and higher-quality surveys keep becoming available, we plan to continue the project for as long as possible.
When will new pairs be added?
Adding new pairs to our subject set will take some time. We rely heavily on classifications from the Galaxy Zoo project, so additional pairs can only be added once new overlaps are identified there. We are most excited for the future Roman data release, as it will provide much higher spatial resolution for these objects!
Why are classifications started from scratch? Isn't your sample from Galaxy Zoo?
In the current iteration of the project (as of March 16, 2026), we are including data from Keel 2013, which was classified using SDSS. However, our project uses a survey with greater depth and higher image quality than SDSS, so we decided to redo the classifications from scratch. In the future, with data from missions such as Roman and Euclid, we may change this so that only the off-centre galaxy is classified, but we are still looking into this.