Galaxy Zoo Green Peas: discovery of a class of compact extremely star-forming galaxies

Carolin Cardamone, Kevin Schawinski, Marc Sarzi, Steven P. Bamford, Nicola Bennert, C. M. Urry, Chris Lintott, William C. Keel, John Parejko, Bob Nichol, Daniel Thomas, Dan Andreescu, Phil Murray, M. Jordan Raddick, Anze Slosar, Alex Szalay, Jan Vandenberg