by Liu et al. (2014), that a comet had impacted with Earth in AD 773 Jan bringing sufficient $^{14}$C and $^{10}$Be, was falsified by Chapman et al. (2014), who could show that this comet was observed as normal comet with a long tail in different nights from both China and Japan.

HN13 also showed that all observables of the AD 774/5 event are consistent with a short gamma-ray burst (GRB). More recently, Pavlov et al. (2013 a,b) confirmed the approximate estimates by HN13 with more precise calculations using GEANT and could show that a Galactic [*long*]{} GRB is also not inconsistent with the AD 774/5 observables. Given the energy estimate by Miyake et al. (2012), HN13 estimated the distance towards the short GRB to be $\sim 0.1$ to $\sim 4$ kpc (again, $\sqrt{4-6}$ times more distant for the Usoskin et al. (2013) energy estimate, i.e. up to $\sim 9$ kpc including the Galactic Center) - but probably outside of 1 kpc, because there was no mass extinction event on Earth around AD 774. A short GRB is expected to be due to the merger of two compact objects like black holes or neutron stars, possibly also white dwarfs. The occurence 