http://dspace.nbuv.gov.ua:80/handle/123456789/37404 Wed, 15 Apr 2026 08:48:52 GMT 2026-04-15T08:48:52Z http://dspace.nbuv.gov.ua:80/bitstream/id/107150/ http://dspace.nbuv.gov.ua:80/handle/123456789/37404 http://dspace.nbuv.gov.ua:80/handle/123456789/119952 Formal estimation of the random component in global maps of total electron content Choliy, V.Ya. Random component of the total electron content (TEC) maps, produced by global navigation satellite system processing centres, was analysed. Helmert transform (HT) and two-dimension singular spectrum analysis (2dSSA) were used. Optimal parameters (in the sense calculation speed versus quality) of the 2dSSA windows were determined along with precision estimations. Fri, 01 Jan 2016 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/119952 2016-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/119951 Observation of the new emission line at ~3.5 keV in X-ray spectra of galaxies and galaxy clusters Iakubovskyi, D.A. The detection of an unidentified emission line in the X-ray spectra of cosmic objects would be a `smoking gun'signature for the particle physics beyond the Standard Model. More than a decade of its extensive searches results in several narrow faint emission lines reported at 3.5, 8.7, 9.4 and 10.1 keV. The most promising of them is the emission line at ∼3.5 keV reported in spectra of several nearby galaxies and galaxy lusters. Here I summarize its up-to-date status, overview its possible interpretations, including an intriguing connection with the radiatively decaying dark matter, and outline future directions for its studies. Fri, 01 Jan 2016 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/119951 2016-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/119950 Multipoint observations of Ionospheric Alfvén Resonance Baru, N.A.; Koloskov, A.V.; Yampolsky, Y.M.; Rakhmatulin, R.A. Among the processes that form properties of the geospace in the circumterrestrial plasma the electromagnetic resonances of the Earth, such as Schummann Resonance (SR) and Ionospheric Alfvén Resonance (IAR) are of great importance. IAR is more localized in space than SR and its properties largely depend on the characteristics of the propagation medium. In contrast to the SR, which has global nature and which is continuously observable at any time of the day, IAR signals are registered mostly during the nighttime and demonstrate more variability of the parameters than SR signals. At the Earth surface IAR is registered as Spectral Resonance Structure of the natural electromagnetic noise at frequency range 0.1-40 Hz. In this work we studied an influence of the environment characteristics on IAR parameters by the means of multipoint observations. Annual data series recorded at Ukrainian Antarctic Station "Akademik Vernadsky", Low Frequency Observatory of the Institute of Radio Astronomy near Kharkov (Ukraine) and magnetic station of Sayan Solar Observatory Mondy near Irkutsk (Russia) were used for the analysis. We investigated the behaviour of IAR parameters, such as probability of resonance lines registration and frequency spacing ∆F, for annual and diurnal intervals. These parameters were compared with characteristics of the ionosphere above all of the observation points and geomagnetic activity. Fri, 01 Jan 2016 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/119950 2016-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/119949 Search for the astrophysical sources of the Fly's Eye event with the highest to date cosmic ray energy E=3.2·10²⁰ eV Gnatyk, R.B.; Kudrya, Yu.N.; Zhdanov, V.I. Among the registered extremely high energy cosmic rays (EHECR, E > 10²⁰ eV) an event with the highest to date energy of E = 3.2 · 10²⁰ eV was detected by the Fly's Eye experiment (FE event) in 1991. With the use of the back-tracking method for the calculation of the EHECR trajectories in Galactic and extragalactic magnetic fields, we show that the galaxies UGC 03574 and UGC 03394 are the most promising candidates among the nearby extragalactic sources for the cases of iron and C-N-O group primary nucleus respectively. The most likely accelerating mechanisms are the newly-born millisecond pulsars, magnetar ares and tidal disruption events in these galaxies. Fri, 01 Jan 2016 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/119949 2016-01-01T00:00:00Z