We present the earliest astronomical observation of a high-energy neutrino error box of which the variability was discovered after high-energy-neutrino detection. The one robotic telescope of the ...MASTER global international networks automatically imaged the error box of the very high-energy-neutrino event IceCube-170922A. Observations were carried out in minutes after the IceCube-170922A neutrino event was detected by the IceCube observatory at the South Pole. MASTER found the blazar TXS 0506+056 to be in the off-state after one minute and then switched to the on-state no later than two hours after the event. The effect is observed at a 50 significance level. We also present own a unique 16 yr light curve of blazar TXS 0506+056 (518 data set).
Usually a thunderstorm region with lightning activity is necessary for the formation of known types of upper atmospheric transient luminous events (TLEs: sprites, emission of light and very low ...frequency perturbation, blue jets, etc.) with well-recognizable visible emissions. However, some "far-from-thunderstorm" transient events have been detected in some experiments. Measurements of transient atmospheric events (TAEs) were made on board the Vernov satellite by the sensitive UV and IR detector. Remote observation from the satellite's orbit provided measurements all over the globe and allowed us to study events associated with thunderstorms (lightning, TLEs) and unusual UV flashes (UV TAEs) far from thunderstorm regions. More than 8500 UV TAEs were measured by the Vernov satellite over the globe. Forty seven far-from-thunderstorm TAEs were selected having no lightning discharges during 1 h in a radius of 1000 km around the location of the event according to the Worldwide Lightning Location Network (WWLLN) and Vaisala Global Lightning Data Set (GLD360) data. Special attention was given to six events with complicated temporal structure and low luminosity in the IR channel. Their properties and atmospheric conditions were studied in detail. The analysis of cloud cover in addition to the lightning location networks data demonstrated the low probability of any lightning in the region of measurements.
ABSTRACT
We report on MASTER optical observations of an afterglow-like optical and X-ray transient AT2021lfa/ZTF21aayokph. We detected the initial steady brightening of the transient at 7σ confidence ...level. This allowed us to use smooth optical self-similar emission of GRBs model to constrain the explosion time to better than 14 min as well as to estimate its initial Lorentz factor Γ0 = 20 ± 10. Taking into consideration the low Γ0 and non-detection in gamma-rays, we classify this transient as the first failed GRB afterglow.
Electron fluxes with energies >0.3 MeV have been measured on the SiriusSat-1 satellite in the final stage of its flight in the altitude range from ~400 to 180 km in the region of the South Atlantic ...anomaly. The existing models of distributions of electron fluxes in the near-Earth space such as the АЕ8 and АЕ9 models primarily concern trapped particles in radiation belts at altitudes above 400 km. Data on subrelativistic electron fluxes at altitudes below 300 km are almost absent. Since the SiriusSat-1 satellite operated until its burning in the atmosphere, unique measurements of the altitude behavior of subrelativistic electron fluxes have been performed, in particular in the region of the South Atlantic anomaly.
The use of the normalized range method for an analysis of the fast variability of electron fluxes in near-Earth space is proposed. This method makes it possible to conclude whether a uniform time ...series corresponds to a random process, or whether there are memory effects or excessive variability. This study analyzes the
SiriusSat
experiment data. We used data on the time of each particle interaction in the detector with an accuracy of ~20 μs, which makes it possible to study variations in electron fluxes of subrelativistic energies on subsecond time scales. In some cases, the value of the Hurst exponent indicates excessive flux variability in the gap region (
) east of the South Atlantic anomaly at characteristic times of 0.6–0.9 s.
The propagation of cosmic ray particles in the atmosphere is modeled and altitude profiles are calculated for radiation dose rates behind aluminum shielding of different thicknesses. Results could ...serve as the basis for a system for monitoring radiation exposure during flights of aircraft.
This paper presents data on the simultaneous and complementary observations of the gamma-ray burst (GRB) GRB 161017A for optical, X-ray, and gamma wavelengths obtained by the Russian multi-messenger ...Lomonosov space observatory and supplemented by additional data from the Swift satellite as well as the ground-based MASTER Global Robotic Net and the 10 m Gran Telescopio Canarias. Multifrequency spectra of this very powerful explosion indicate that it originated at a distance of 10 billion light years from Earth. Here, we present the results of the prompt, early, and afterglow optical observations. The light curves and spectra suggest that the prompt optical and high-energy emissions occur in the same region near the GRB source.
Problems associated with observations and interpretation of the physical mechanisms underlying the generation of hard electromagnetic radiation from lightning discharges are considered. A review of ...modern problems of understanding the nature of atmospheric flashes of gamma radiation from the Earth’s atmosphere is given. The results of orbital observations, in particular, on the
Vernov
satellite, are analyzed. The possibilities of orbital observations of atmospheric gamma-ray flashes on CubeSat spacecraft are discussed, and a description of the recording equipment is given. The technique of a laboratory experiment with long sparks, which simulates electrical discharges in thunderclouds, is considered.
Onboard the spacecraft Lomonosov is established two fast, fixed, very wide-field cameras SHOK. The main goal of this experiment is the observation of GRB optical emission before, synchronously, and ...after the gamma-ray emission. The field of view of each of the cameras is placed in the gamma-ray burst detection area of other devices located onboard the “Lomonosov” spacecraft. SHOK provides measurements of optical emissions with a magnitude limit of
∼
9
–
10
m
on a single frame with an exposure of 0.2 seconds. The device is designed for continuous sky monitoring at optical wavelengths in the very wide field of view (1000 square degrees each camera), detection and localization of fast time-varying (transient) optical sources on the celestial sphere, including provisional and synchronous time recording of optical emissions from the gamma-ray burst error boxes, detected by the BDRG device and implemented by a control signal (alert trigger) from the BDRG. The Lomonosov spacecraft has two identical devices, SHOK1 and SHOK2. The core of each SHOK device is a fast-speed 11-Megapixel CCD. Each of the SHOK devices represents a monoblock, consisting of a node observations of optical emission, the electronics node, elements of the mechanical construction, and the body.
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