A luminosity distribution for kilonovae based on short gamma-ray burst afterglows
The combined detection of a gravitational-wave signal, kilonova, and short gamma-ray burst (sGRB) from GW170817 marked a scientific breakthrough in the field of multimessenger astronomy. But even before GW170817, there have been a number of sGRBs with possible associated kilonova detections. In this work, we re-examine these 'historical' sGRB afterglows with a combination of state-of-the-art afterglow and kilonova models. This allows us to include optical/near-infrared synchrotron emission produced by the sGRB as well as ultraviolet/optical/near-infrared emission powered by the radioactive decay of r-process elements (i.e. the kilonova). Fitting the light curves, we derive the velocity and the mass distribution as well as the composition of the ejected material. The posteriors on kilonova parameters obtained from the fit were turned into distributions for the peak magnitude of the kilonova emission in different bands and the time at which this peak occurs. From the sGRB with an associated kilonova, we found that the peak magnitude in H bands falls in the range [−16.2, −13.1] (95 per cent of confidence) and occurs within 0.8−3.6d after the sGRB prompt emission. In g band instead we obtain a peak magnitude in range [−16.8, −12.3] occurring within the first 18 h after the sGRB prompt. From the luminosity distributions of GW170817/AT2017gfo, kilonova candidates GRB130603B, GRB050709, and GRB060614 (with the possible inclusion of GRB150101B, GRB050724A, GRB061201, GRB080905A, GRB150424A, and GRB160821B) and the upper limits from all the other sGRBs not associated with any kilonova detection we obtain for the first time a kilonova luminosity distribution in different bands.
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model) Accepted 2019 March 24. Received 2019 March 24; in original form 2018 November 13. This work was initiated and supported by the 2017 Kavli Summer Program in Astrophysics at the Niels Bohr Institute in Copenhagen, and the authors would like to thank DARK at the University of Copenhagen for incredible hospitality. The 2017 Kavli Summer Program was supported by the Kavli Foundation, Danish National Research Foundation (DNRF), the Niels Bohr International Academy, and DARK. AMB acknowledges support from a UCMEXUS-CONACYT Doctoral Fellowship. MC is supported by the David and Ellen Lee Postdoctoral Fellowship at the California Institute of Technology. TD acknowledges support by the European Union's Horizon 2020 research and innovation program under grant agreement No. 749145, BNSmergers. RJF is supported in part by NASA grant NNG17PX03C, NSF grant AST-1518052, the Gordon & Betty Moore Foundation, the Heising-Simons Foundation, and by fellowships from the Alfred P. Sloan Foundation and the David and Lucile Packard Foundation. ER-R is supported in part by David and Lucile Packard Foundation and the Niels Bohr Professorship from the DNRF. SA acknowledges Giulia Stratta, Daniele Malesani, Andrea Melandri, and Enzo Brocato for useful discussions. The authors acknowledge the anonymous referee for his/her suggestions that help us to improve the presentation of our results.
Accepted Version - 1811.05506.pdf
Published - stz891.pdf