Swift follow-up of gravitational wave triggers: Results from the first aLIGO run and optimization for the future

This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This research has made use of the XRT Data Analysis Software (XRTDAS) developed under the responsibility of the ASI Science Data Center (ASDC), Italy. This research has also made use of the SIMBAD data base, operated at CDS, Strasbourg, France. The GW probability maps and our related galaxy maps are in HEALPIX format (Gorski et al. ´ 2005). PAE, JPO and KLP acknowledge UK Space Agency support. SC and GT acknowledge ASI for support (contract I/004/11/1). MB is supported by the Netherlands Organisation for Scientific Research, NWO, through grant number 614.001.451; through FP7 grant number 279396 from the European Research Council; and by the Polish National Science Centre under contract #UMO-2012/07/D/ST9/02785.