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Galactic sites of acceleration of cosmic rays to energies of order 1015 eV and higher, dubbed PeVatrons, reveal themselves by recently discovered gamma radiation of energies above 100 TeV. However, joint gamma-ray and neutrino production, which marks unambiguously cosmic-ray interactions with ambient matter and radiation, was not observed until now. In 2020 November, the IceCube neutrino observatory reported an ∼150 TeV neutrino event from the direction of one of the most promising Galactic PeVatrons, the Cygnus Cocoon. Here we report on the observation of a 3.1σ (post-trial) excess of atmospheric air showers from the same direction, observed by the Carpet–2 experiment and consistent with a few months flare in photons above 300 TeV, in temporal coincidence with the neutrino event. The fluence of the gamma-ray flare is of the same order as that expected from the neutrino observation, assuming the standard mechanism of neutrino production. This is the first evidence for the joint production of high-energy neutrinos and gamma-rays in a Galactic source.

A review of the present-day situation in the experimental studies of variations of cosmic rays during thunderstorms is given. It is shown that these experiments can be a useful tool for studying very interesting physical effects in the electrically disturbed atmosphere. The main emphasis is laid on the experimental verification of the runaway breakdown theory and on the role of cosmic rays in the processes of lightning initiation.

Road. Durham DHI 3LE, UK Received 8 N o v e m h r I991 Ahslmct. On 23 February 1989 an apparent bun1 of ultra-high energy gamma-rays was uharlvcd imnr lhr dircl-lion ui thc Crab Nebula hy thr Baksan Air Shower Army. l 3 h e resull of checking and reanalysis oi these data is reponed. n e excess in the number of wents n h v r lnckgmund has a reduccd slalistical signilicancc hul this is compensated for B phase analysis wlh rwpcct to 1hc Cmb pulsar cycle which shows the ~[ccss lo hvaur one phase bin. 'lhc agreement ol 1hc evidence irom other arrays is discussed.We first reported the Crab event of 23 February 1989, an apparent burst of gammarays with energies above -200 X V observed with the Baksan Air Shower Array (BASA), at the Crimea Workshop on W E Gamma Ray ATtronomy [l]. Unlike the three day enhancement of daily ONiOFF ratio for Cyg X-3 in October 1985 [2],when the search was stimulated by the observation of a radio-burst, this Crab event was found simply as the most extreme fluctuation of the daily ratio in 1256 days of obselvation between 1985 and 1989. Our publication stimubated searches in their data