This site is designed for astronomers to apprehend and plan follow-up observations after a gravitational wave (GW) candidate event is distributed by the LIGO-Virgo observatories, which are expected to start operations in 2015. The sky location is not well known, rather it is arcs and blobs of probability-density, a huge (constellation-sized) area to search on the sky.

The Skymap Viewer is a multi-scale, multi-wavelength sky viewer enabling drill-down from whole-sky to arc-second resolution, including image surveys such as DSS, SDSS, VTSS, Fermi, and Galex. Also shown are the sun, moon, and milky way relative to the skymap, at any user-chosen time and location on the Earth. There are also catalogs of objects that may harbor the GW source, such as galaxies and galaxy clusters, and each catalog source can be drilled down to the SIMBAD and NED databases. The left panel of the Viewer shows the capabilities, with red help buttons for more information. Skymap Viewer uses the Sinus projection of the sky (parallel projection of a sphere), and so only half the sky is shown at a time. Users should pan around to see the other side of the sky.

The set of skymaps that we use to show Skymap Viewer are from a data release associated with [Singer 2014] henceforth First2Years, that simulated how the LIGO-Virgo detectors are expected to improve from 2015 to 2016. A large number of 'binary neutron star' collisions were simulated, along with the detector response, to show astronomers what they might expect when the news of a detection arrives suddenly -- as it will -- and fast response is needed over minutes, hours and days.

The skymap is shown as a contour plot, each line enclosing a given percentage of the total probability, with the color key shown to the right (more about the contour plots). We state here that the skymaps labeled 'Rapid' are computed in such a way that they do not prepresent probability density without further calibration. An approximate power-law calibration has been applied to make these contour plots. We should state that the contour plot may not be as accurate in representing the skymap as the original FITS file from which it is derived, and that the calibration we have used is simply a fit to published data.

Click here to select a skymap to view.