@article{afc7985cd8104297934c869e77c535db,
title = "The X-ray counterpart to the gravitational-wave event GW170817",
abstract = "A long-standing paradigm in astrophysics is that collisions-or mergers-of two neutron stars form highly relativistic and collimated outflows (jets) that power γ-ray bursts of short (less than two seconds) duration. The observational support for this model, however, is only indirect. A hitherto outstanding prediction is that gravitational-wave events from such mergers should be associated with γ-ray bursts, and that a majority of these bursts should be seen off-axis, that is, they should point away from Earth. Here we report the discovery observations of the X-ray counterpart associated with the gravitational-wave event GW170817. Although the electromagnetic counterpart at optical and infrared frequencies is dominated by the radioactive glow (known as a kilonova') from freshly synthesized rapid neutron capture (r-process) material in the merger ejecta, observations at X-ray and, later, radio frequencies are consistent with a short γ-ray burst viewed off-axis. Our detection of X-ray emission at a location coincident with the kilonova transient provides the missing observational link between short γ-ray bursts and gravitational waves from neutron-star mergers, and gives independent confirmation of the collimated nature of the γ-ray-burst emission.",
author = "E. Troja and L. Piro and {Van Eerten}, H. and Wollaeger, {R. T.} and M. Im and Fox, {O. D.} and Nathaniel Butler and Cenko, {S. B.} and T. Sakamoto and Fryer, {C. L.} and R. Ricci and A. Lien and Ryan, {R. E.} and O. Korobkin and Lee, {S. K.} and Burgess, {J. M.} and Lee, {W. H.} and Watson, {A. M.} and C. Choi and S. Covino and P. D'Avanzo and Fontes, {C. J.} and {Becerra Gonz{\'a}lez}, J. and Khandrika, {H. G.} and J. Kim and Kim, {S. L.} and Lee, {C. U.} and Lee, {H. M.} and A. Kutyrev and G. Lim and R. S{\'a}nchez-Ram{\'i}rez and S. Veilleux and Wieringa, {M. H.} and Y. Yoon",
note = "Funding Information: Acknowledgements We acknowledge the advice and contribution of N. Gehrels, who was co-investigator of our Chandra and Hubble Space Telescope observing programs. We thank B. Wilkes and the Chandra X-ray Center staff, N. Reid and the Space Telescope Science Institute (STScI) staff, J. Stevens and the CSIRO staff, L. Ferrarese and the Gemini support staff, in particular R. Salinas, M. Andersen, H. Kim, P. Candia and K. Silva. E. Troja thanks Bianca A. Vekstein, A. Bersich and F. Troja for help during the preparation of this manuscript. We thank V. Bajaj (STScI) and S. Hernandez for their assistance with data reduction. Work at LANL was done under the auspices of the National Nuclear Security Administration of the US Department of Energy at Los Alamos National Laboratory (LANL) under contract number DE-AC52-06NA25396. All LANL calculations were performed on LANL Institutional Computing resources. This research used resources provided by the LANL Institutional Computing Program, which is supported by the US Department of Energy National Nuclear Security Administration under contract number DE-AC52-06NA25396. M.I., S.-K.L., J.K., C.C., G.L., and Y.Y. acknowledge support from NRFK grant number 2017R1A3A3001362, funded by the Korean government. Work by C.-U.L. and S.-L.K. was supported by the KASI (Korea Astronomy and Space Science Institute) grant 2017-1-830-03. This research made use of the KMTNet system operated by KASI, and the data were obtained at three Cerro-Tololo Inter-American Observatory host sites in Chile, the South African Astronomical Observatory in South Africa, and the Siding Spring Observatory in Australia. E. Troja acknowledges support from grants GO718062A and HSTG014850001A. R.S.-R. acknowledges support by the Italian Space Agency through contract number 2015-046-R.0 and by the European Union Horizon 2020 Programme under the AHEAD project (grant agreement number 654215). T.S. acknowledges support by MEXT KAKENHI (grant numbers 17H06357 and 17H06362). Publisher Copyright: {\textcopyright} 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.",
year = "2017",
month = nov,
day = "2",
doi = "10.1038/nature24290",
language = "English (US)",
volume = "551",
pages = "71--74",
journal = "Nature",
issn = "0028-0836",
publisher = "Nature Publishing Group",
number = "7678",
}