DECam and LIGO: Binary Black Hole Mergers and Kilonovae

We are using the Dark Energy Camera to followup LIGO events. The LIGO observatory has become a productive observatory of gravitational wave events- binary compact object mergers. LIGO's observing run 1 and 2 produced publications describing 5.9 binary black hole mergers and one binary neutron star merger. LIGO's run 3 begins next year. We'll go over GW parameter estimation (for astronomers!), so that we can understand the distance/inclination degeneracy. Then we'll cover the DESGW program's observations of the O1 & O2 binary black hole mergers. Next we will describe the binary neutron star merger event, and our collaboration's series of observations designed to physically understand the remnant kilonova. The resulting model is of relatively low opacity material from the collision being ejected out the poles while high opacity material fills the equatorial disk. Lanthanide dominated matter driven off the remnant by strong neutrino winds are the dominant source of luminosity at several days after the merger. Lastly, we'll think about how we can constrain the inclination of kilonovae and thus better constrain the GW distance to the source with the aim of precision Hubble Constant measurements. A better Hubble Constant helps understanding the Dark Energy Survey cosmology measurements.