“Isotopic footprints” of gamma-ray and proton events and anomalous signal in radiocarbon in 775 AD

Variations of 14C around AD 775 and AD 1795 – due to solar activity

“…The TUNU data set does not even cover AD 774/5, so that it is not clear whether the peak seen in AD 768 is the largest one (data only from 763-770). For the NEEM data set around AD 993/4, they took data for only 13 years, so that the identification of the peak presumably related to the 14 C variation around AD 993/4 is also un- 19 Pavlov et al (2013Pavlov et al ( , 2014) expect a short recombination airglow in 30-40 km height with (4-5) ×10 6 erg cm −2 fluence after a gamma-ray burst, but there is no such evidence: the observations in the Chronicle of Zuqnin for AD 772 and 773 (and maybe also 774) clearly refer to normal aurora curtains with red and yellow color, and a report from the Ulster Chronicle for Ireland for AD 772 September 29 (The hand-clapping on St Michael's Day which called fire from heaven.) also refers to an aurora (fire from heaven), if a celestial event, see Neuhäuser & Neuhäuser (2015a) for discussion (aurorae are usually above 100 km); a gamma-ray burst would also have led to strong ozone layer depletion and weather disturbances (e.g.…”

“…also refers to an aurora (fire from heaven), if a celestial event, see Neuhäuser & Neuhäuser (2015a) for discussion (aurorae are usually above 100 km); a gamma-ray burst would also have led to strong ozone layer depletion and weather disturbances (e.g. Pavlov et al 2014), which are not reported (at least for the northern hemisphere). 20 Without the data point for 769.5 in TUNU, which we did not want to assign arbitrarily to either the 769 or the 770 year -if we would include this data point with low 10 Be flux in taking the means, the peak in Fig.…”

“…If the 10 Be peak in the AD 780s (Horiuchi et al 2008) and the 14 C increase around AD 775 would be due to the same cause, and if 4-6 times less 14 C was produced than estimated by M12 , then 45-68 times more 14 C was produced than 10 Be (scaling from Hambaryan & Neuhäuser 2013). According to calculations by , ∼ 56 times more 14 C than 10 Be can be produced in solar flares, while according to Pavlov et al (2014), only 16-17 times more 14 C than 10 Be can be produced in solar flares.…”

“…Stratospheric ionization due to a Short Gamma-Ray Burst (few seconds) would deplete the local ozone layer due to NO x mainly around the sub-stellar point; this leads to a drop in stratospheric temperature and a rise in tropopause altitude causing larger air mass exchange and injection of radionuclids from the stratosphere into the troposphere (e.g. Pavlov et al 2014). Such effects may effectively disturb in the otherwise normal interhemisperic offset.…”

“…2. While Usoskin et al (2013) assumed that 70 % of the 14 C is produced in the stratosphere and 30 % in the troposphere, Pavlov et al (2013Pavlov et al ( , 2014 used 65 % and 35 %, respectively, 3. An altitude change in the border between those two regions or sudden injection of stratospheric air into the troposphere can lead to strong modifications.…”