https://doi.org/10.1051/epjconf/201610908002
An r−process macronova/kilonova in GRB 060614: evidence for the merger of a neutron star-black hole binary
Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, China
a e-mail: jin@pmo.ac.cn
b e-mail: yzfan@pmo.ac.cn
c e-mail: dmwei@pmo.ac.cn
Published online: 12 February 2016
After the jet break at t ~ 1.4 days, the optical afterglow emission of the long-short burst GRB 060614 can be divided into two components. One is the power-law decaying forward shock afterglow emission. The other is an excess of flux in several multi-band photometric observations, which emerges at ~4 days after the burst, significantly earlier than that observed for a supernova associated with a long-duration GRB. At t > 13.6 days, the F814W-band flux drops faster than t−3.2. Moreover, the spectrum of the excess component is very soft and the luminosity is extremely low. These observed signals are incompatible with those from weak supernovae, but the ejection of ~ 0.1 M⊙ of r−process material from a black hole-neutron star merger, as recently found in some numerical simulations, can produce it. If this interpretation is correct, it represents the first time that a multi-epoch/band lightcurve of a Li-Paczynski macronova (also known as kilonova) has been obtained and black hole-neutron star mergers are sites of significant production of r−process elements.
© Owned by the authors, published by EDP Sciences, 2016
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
