Abstract
This article presents the early results of synchronous multiwavelength observations of one of the brightest gamma-ray bursts (GRBs) GRB 160625B with the detailed continuous fast optical ...photometry of its optical counterpart obtained by MASTER and with hard X-ray and gamma-ray emission, obtained by the Lomonosov and Konus-Wind spacecraft. The detailed photometry led us to detect the quasi-periodical emission components in the intrinsic optical emission. As a result of our analysis of synchronous multiwavelength observations, we propose a three-stage collapse scenario for this long and bright GRB. We suggest that quasiperiodic fluctuations may be associated with forced precession of a self-gravitating rapidly rotating superdense body (spinar), whose evolution is determined by a powerful magnetic field. The spinar’s mass allows it to collapse into a black hole at the end of evolution.
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.
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.
This paper presents a catalogue of gamma-ray bursts (GRBs) that were detected by the instruments onboard the Lomonosov space observatory. The Lomonosov mission gave the first experience of not only ...multi-wavelength (from optical to gamma) observations of GRBs but also multi-messenger observations of extreme phenomena and GRBs. The detailed light curves and energy spectra of the detected GRBs are presented. The results of the prompt, early an afterglow optical observations of several GRBs are discussed.
Moscow State University is developing a project for a multi-satellite constellation intended for the monitoring of space radiation. A number of small satellites of CubeSat format were launched into ...selected orbits crossing the wide range of magnetic drift shells. The primary scope for the project is the operational monitoring of near-Earth’s radiation environment, i.e., fluxes of electrons and protons of Earth’s radiation belts and energetic particles of solar and galactic origin. To date, there are four CubeSat satellites operating in near-Earth orbits, which deliver scientific and telemetric data. Thus, for the first time, a unique multi-satellite constellation has been implemented, which makes it possible to simultaneously measure the particle and quantum fluxes at different areas in the near-Earth space using the same type of instruments. A special compact detector of gamma quanta and energetic charged particles (electrons and protons) DeCoR has been developed to carry out radiation monitoring by CubeSats. With their help, observations of various effects of space weather have been made. These effects include a variety of electron fluxes in the outer belt during geomagnetic activity in late November–early December 2021, filling of polar caps by solar energetic particles accelerated in flares occurring in late October–early November, and the existence of stable electron fluxes near the geomagnetic equator.
The study of GRB prompt emissions (PE) is one of the main goals of the Lomonosov space mission. The payloads of the GRB monitor (BDRG) with the wide-field optical cameras (SHOK) and the ultra-fast ...flash observatory (UFFO) onboard the Lomonosov satellite are intended for the observation of GRBs, and in particular, their prompt emissions. The BDRG gamma-ray spectrometer is designed to obtain the temporal and spectral information of GRBs in the energy range of 10–3000 keV as well as to provide GRB triggers on several time scales (10 ms, 1 s and 20 s) for ground and space telescopes, including the UFFO and SHOK. The BDRG instrument consists of three identical detector boxes with axes shifted by
90
∘
from each other. This configuration allows us to localize a GRB source in the sky with an accuracy of
∼
2
∘
.
Each BDRG box contains a phoswich NaI(Tl)/CsI(Tl) scintillator detector. A thick CsI(Tl) crystal in size of
∅
130
×
17
mm
is placed underneath the NaI(Tl) as an active shield in the soft energy range and as the main detector in the hard energy range. The ratio of the CsI(Tl) to NaI(Tl) event rates at varying energies can be employed as an independent metric to distinguish legitimate GRB signals from false positives originating from electrons in near-Earth vicinities.
The data from three detectors are collected in a BA BDRG information unit, which generates a GRB trigger and a set of data frames in output format. The scientific data output is
∼
500
Mb per day, including
∼
180
Mb of continuous data for events with durations in excess of 100 ms for 16 channels in each detector, detailed energy spectra, and sets of frames with
∼
5
Mb of detailed information for each burst-like event. A number of pre-flight tests including those for the trigger algorithm and calibration were carried out to confirm the reliability of the BDRG for operation in space.
Unfolding is currently an important stage of processing experimental data, reducing the effect of errors and reconstructing approximately real distributions of quantities. Numerous approaches exist ...to solve this problem; in particular, they are widely used in the modern physics of atomic nuclei and elementary particles, space physics, and other related areas. However, many algorithms are not designed or are poorly adapted to reconstruct multidimensional distributions corresponding to, e.g., several characteristics of particles measured simultaneously. In this work, a method has been proposed to adapt the singular value decomposition (SVD) unfolding algorithm to the multidimensional case. The proposed modified method has been tested in application to simulation data for the cosmic ray spectrum measured in the PAMELA space experiment. This method not only makes it possible to estimate the real distribution of a multidimensional quantity (momentum and two angles specifying the direction of entering a particle into an instrument) but also provides a better result compared to the classical SVD approach in the one-dimensional case (only the momentum of the p-article).
The authors demonstrate the possibility of using CubeSat nanosatellites to study solar cosmic rays (SCRs). SCR electron fluxes over the polar caps at altitudes of ∼550 km are detected. Measurements ...are made using scintillation detectors of cosmic radiation (DeCoR) mounted on several CubeSat nanosatellites of Moscow State University during an SCR event on September 6–21, 2022.
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.
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.
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