Space Warps: Crowd-sourcing the Discovery of Gravitational Lenses

Gravitational lenses are rare alignments of galaxies, where the massive foreground object causes magnification, distortion and multiple imaging of the background source. They are rare, but very useful objects: they can be used... [ view full abstract ]

Gravitational lenses are rare alignments of galaxies, where the massive foreground object causes magnification, distortion and multiple imaging of the background source. They are rare, but very useful objects: they can be used to weigh the lens galaxies, and as cosmic telescopes. Fully automated lens detection is currently out of reach: instead, tens to hundreds of thousands of targets would need to be visually classified in order to find thousands of lenses in the next generation of astronomical imaging surveys. The Zooniverse project "Space Warps" is a web-based experiment in crowd sourcing that task. I will present the system and some results from the first two projects, focusing on key features such as our agent-based online probabilistic model for interpreting the classification data, the use of simulated lenses both in this analysis and in training the volunteers, how well the system performed relevant to semi-automated methods applied to the same images, and some promising hints for the future.