MNRAS-2016-Evans-1591-602.pdf (1.27 MB)
Download file

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

Download (1.27 MB)
journal contribution
posted on 25.11.2016, 11:09 by P. A. Evans, J. A. Kennea, D. M. Palmer, M. Bilicki, J. P. Osborne, P. T. O'Brien, N. R. Tanvir, A. Y. Lien, S. D. Barthelmy, D. N. Burrows, S. Campana, S. B. Cenko, V. D'Elia, N. Gehrels, F. E. Marshall, K. L. Page, M. Perri, B. Sbarufatti, M. H. Siegel, G. Tagliaferri, E. Troja
During its first observing run, in late 2015, the advanced Laser Interferometer Gravitationalwave Observatory facility announced three gravitational wave (GW) triggers to electromagnetic follow-up partners. Two of these have since been confirmed as being of astrophysical origin: both are binary black hole mergers at ~500 Mpc; the other trigger was later found not to be astrophysical. In this paper, we report on the Swift follow-up observations of the second and third triggers, including details of 21 X-ray sources detected; none of which can be associated with the GW event. We also consider the challenges that the next GW observing run will bring as the sensitivity and hence typical distance of GW events will increase. We discuss how to effectively use galaxy catalogues to prioritize areas for follow-up, especially in the presence of distance estimates from the GW data. We also consider two galaxy catalogues and suggest that the high completeness at larger distances of the 2MASS Photometric Redshift catalogue makes it very well suited to optimize Swift follow-up observations.


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.



Monthly Notices of the Royal Astronomical Society, (October 21, 2016) 462 (2): 1591-1602.

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy


VoR (Version of Record)

Published in

Monthly Notices of the Royal Astronomical Society


Oxford University Press (OUP), Royal Astronomical Society





Acceptance date


Available date


Publisher version


See Erratum at