By davidhydes comment [1] it is because the gamma burst actually happens after the merger. It is caused by the ejected mass slowing down due to friction. My la

By davidhydes comment [1] it is because the gamma burst actually happens after the merger. It is caused by the ejected mass slowing down due to friction. My layman's interpretation is that this is cherenkov radiation on an astronomical scale, though that suggests it is caused by charged particles, which neutrons aren't. [1] https://news.ycombinator.com/item?id=15484357 https://news.ycombinator.com/item?id=15484357