Relationships among detector signals recorded during events SN1987A and GW170817

The temporal coincidences of events detected in four neutrino detectors and two gravitational antennas still remains among the most puzzling phenomena associated with SN1987A. The coincidences form a six-hour signal approximately coincident in time with the well-known LSD signal at 2h52m UT on 23/02/1987. After 30 years of research, the characteristics and the shape of the six-hour signal have been studied quite well, but the mechanisms of its formation have not been fully understood as of yet. Here we suggest that data obtained from another technology, radioactive decays, might provide new insights into the origin of signals previously seen in neutrino detectors and gravity wave detectors. On August 17, 2017, at 12h41m UT, the GW170817 signal was detected by LIGO and Virgo. At the same time, an approximately 7-hour long signal coincident with GW170817 was detected in the Si/Cl experiment on precision measurement of the $^{32}$Si half-life. We show that the Si/Cl signal is unexpectedly similar to the six-hour signal from SN1987A. In addition, we establish that the sources of the coinciding events are similar to those of the Si/Cl signal. To explain the surprising similarities in both signals, we present a mechanism which could in principle account for this phenomenon in terms of a local increase in the density of axionic dark matter induced by a gravity wave.