TITLE: GCN CIRCULAR NUMBER: 26244 SUBJECT: Announcing the GW Treasure Map DATE: 19/11/13 22:00:19 GMT FROM: Aaron Tohuvavohu at U Toronto Samuel Wyatt (U Arizona), Aaron Tohuvavohu (U Toronto), Iair Arcavi (Tel Aviv University), David Sand, Michael Lundquist (U Arizona), D. Andrew Howell, Curtis McCully, Austin Riba, and Jamison Burke (Las Cumbres Observatory/UCSB) report on behalf of the Gravitational Wave Treasure Map team: The Gravitational Wave Treasure Map (http://treasuremap.space, Wyatt et al. in prep) is designed to help coordinate electromagnetic followup of gravitational-wave (GW) events. It allows observers to easily report their planned and executed observations in search of counterparts to GW events, and everyone to query the reports of other observers in a programatic way via a documented and easy-to-use API. The goal is to enable coordination between observatories and teams in order to minimize unnecessary overlap in these searches and find the counterpart as quickly and as efficiently as possible. The Treasure Map also serves as a central repository for the metadata (pointing, time, band, depth) of pointings performed in response to GW triggers to allow for easy post-facto assessment of the world-wide multi-wavelength coverage. It also includes GRB mission prompt coverage, a visualization engine, and quantitative calculator for coverage as a function of time with optional cuts on instruments, band, and/or depth. Treasure Map is intended as a community resource, and new features are continuously being added. Suggestions from members of the community are welcome. The Neil Gehrels Swift Observatory (UVOT, XRT, BAT), Las Cumbres Observatory, SAGUARO (Catalina Sky Survey), and Fermi/GBM teams have already committed to posting their pointing plans, as well as completed pointings, to the Treasure Map. Other groups are also participating. We invite the entire community to take part, and work to optimize the global search for electromagnetic counterparts to gravitational wave events.