Related papers: Wind-induced Natural Gamma Radiation
Gamma-Ray Bursts (GRBs) directed at Earth from within a few kpc may have damaged the biosphere, primarily though changes in atmospheric chemistry which admit greatly increased Solar UV. However, GRBs are highly variable in spectrum and…
We present one possible mechanism for the giant flares of the Soft Gamma-Ray Repeaters (SGRs) within the framework of magnetar, i.e., superstrongly magnetized neutron star model, motivated by the positive period increase associated with the…
We observed three $\gamma$-ray bursts related to thunderclouds in winter using the prototype of anti-neutrino detector PANDA made of 360-kg plastic scintillator deployed at Ohi Power Station at the coastal area of the Japan Sea. The maximum…
During a winter thunderstorm on 2017 November 24, a strong burst of gamma rays with energies up to $\sim$10~MeV was detected coincident with a lightning discharge, by scintillation detectors installed at Kashiwazaki-Kariwa Nuclear Power…
We present the first experimental evidence for in-ice radiofrequency emission from high-energy particle cascades developing in the Antarctic ice sheet. In 208 days of data recorded with the phased-array trigger of the Askaryan Radio Array,…
Thunderstorms produce strong electric fields over regions on the order of kilometer. The corresponding electric potential differences are on the order of 100 MV. Secondary cosmic rays reaching these regions may be significantly accelerated…
Soft gamma repeaters (SGRs) are "magnetars", a small class of slowly spinning neutron stars with extreme surface magnetic fields, ~10^15 gauss. On 2004 December 27, a giant flare was detected from the magnetar SGR 1806-20, the third such…
The observation by the BATSE instrument on the Compton Gamma Ray Observatory that gamma-ray bursts (GRBs) are distributed isotropically around the Earth but nonuniformly in distance has led to the widespread conclusion that GRBs are most…
The degree of beaming in Gamma-Ray Bursts (GRBs) is currently unknown. The uncertainty in the gamma-ray beaming angle, theta, leaves the total energy release (proportional to theta^2) and the event rate per galaxy (proportional to…
A report is made on a comprehensive observation of a burst-like $\gamma$-ray emission from thunderclouds on the Sea of Japan, during strong thunderstorms on 2007 January 6. The detected emission, lasting for $\sim$40 seconds, preceded…
Quiescence and burst emission and relativistic particle winds of soft gamma-ray repeaters (SGRs) have been widely interpreted to result from ultrastrongly magnetized neutron stars. In this magnetar model, the magnetic energy and…
Non-thermal magnetospheric processes in the vicinity of supermassive black holes have attracted particular attention in recent times. Gap-type particle acceleration accompanied by curvature and Inverse Compton radiation could in principle…
We present a survey of more than half a thousand thunderstorm ground enhancements, fluxes of electrons, and gamma rays associated with thunderstorms registered from 2008 to 2022 at Aragats space environmental center. We analyze correlations…
The extragalactic gamma-ray sky is dominated by two classes of sources: Gamma-Ray Bursts (GRBs) and radio loud active galactic nuclei whose jets are pointing at us (blazars). We believe that the radiation we receive from them originates…
Proceeding from a stormy day of 22 September 2022, when 7 thunderstorm ground enhancements occurred (TGEs, 3 of them very large), we perform an analysis of the most important conditions, on which depend the origination of the large particle…
A theory is proposed to explain with simplicity the basic observed properties of a Gamma Ray Burst (GRB). It employs a well-known result of Schwinger, that static electric fields in excess of a critical value are unstable to pair creation,…
We show that the mysterious, rapidly variable emission at ~400 MeV observed from the Crab Nebula by the AGILE and Fermi experiments could be the result of a sudden drop in the mass-loading of the pulsar wind. The current required to…
Fast radio bursts (FRBs) are bright radio bursts originating at cosmological distances. Only three repeating FRBs FRB 20121102A, FRB 20190520B and FRB 20201124A among $\sim$ 60 known repeating FRBs have circular polarization. We observed…
We report the AGILE observations of GRB 220101A, which took place at the beginning of 1st January 2022 and was recognized as one of the most energetic gamma-ray bursts (GRBs) ever detected since their discovery. The AGILE satellite acquired…
Gamma-Ray Bursts (GRBs) are extra-galactic and extremely energetic transient emissions of gamma rays, which are thought to be associated with the death of massive stars or the merger of compact objects in binary systems. Their huge…