We estimated the magnetic field strength at the event horizon for a sample of supermassive black holes (SMBHs) in active galactic nuclei (AGNs).
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We present results from VLBI observations of continuum and OH line emission in IRAS 02524+2046 as well as arcsecond-scale radio properties of this galaxy using VLA archive data.
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In solar flares the presence of magnetohydrodynamic turbulence is highly probable. However, information about this turbulence, especially the magnetic field turbulence, is still very limited.
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Observational information on high-energy astrophysical neutrinos is being continuously collected by the IceCube observatory. However, the sources of the neutrinos are still unknown. In this study, we use radio very long baseline interferometry (VLBI) data for a complete VLBI flux density-limited sample of active galactic nuclei (AGNs).
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The presented observation results of the blazar J0238+1636 were obtained in: 2014-2019 with the RATAN-600 radio telescope from the Special Astrophysical Observatory of the Russian Academy of Sciences at 2.3, 4.8, 8.2, 11.2, and 21.7 GHz; and 2015-2017 with the 32-m Zelenchuk and Badary radio telescopes of the Institute of Applied Astronomy of the Russian Academy of Sciences at 4.84 and 8.57 GHz.
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A light bridge is a prominent structure commonly observed within a sunspot. Its presence usually triggers a wealth of dynamics in a sunspot and has a lasting impact on sunspot evolution.
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It is possible to reduce the discrepancy between the local measurement of the cosmological parameter H_0 and the value derived from the Planck measurements of the cosmic microwave background (CMB) by considering contamination of the CMB by emission from some medium around distant extragalactic sources, such as extremely cold coarse-grain dust.
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We report the results of decade-long (2008-2018) γ-ray to 1 GHz radio monitoring of the blazar 3C 279, including GASP/WEBT, Fermi and Swift data, as well as polarimetric and spectroscopic data.
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The analysis of the spectral characteristics of the burst radio emission on June 21, 2011 was carried out on the basis of an improved methodology for determining harmonic numbers for the corresponding stripes of the zebra structure.
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We investigate quasi-periodic pulsations (QPPs) of high-energy nonthermal emissions from an X9.3 flare (SOL2017-Sep-06T11:53), the most powerful flare since the beginning of solar cycle 24.
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The relatively large-amplitude decaying regime of transverse oscillations of coronal loops has been known for two decades and has been interpreted in terms of magnetohydrodynamic kink modes of cylindrical plasma waveguides.
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Gigahertz-Peaked spectrum (GPS) sources are compact active galactic nuclei, presumably young precursors of bright radio sources. The study of GPS radio properties provides information about the features of synchrotron radiation in extragalactic sources.
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We present a multiwavelength study of the flat-spectrum radio quasar CTA 102 during 2013-2017. We use radio-to-optical data obtained by the Whole Earth Blazar Telescope, 15 GHz data from the Owens Valley Radio Observatory, 91 and 103 GHz data from the Atacama Large Millimeter Array, near-infrared data from the Rapid Eye Monitor telescope, as well as data from the Swift (optical-UV and X-rays) and Fermi (γ-rays) satellites to study flux and spectral variability and the correlation between flux changes at different wavelengths.
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Анализируются механизмы формирования абсорбции в спектре космического микроволнового фона (CMB) на частоте линии 21 см перехода между подуровнями сверхтонкой структуры основного состояния атома водорода.
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The ubiquity of recently discovered low-amplitude decayless kink oscillations of plasma loops allows for the seismological probing of the corona on a regular basis.
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Context. Rapidly decaying slow magnetoacoustic waves are regularly observed in the solar coronal structures, offering a promising tool for a seismological diagnostics of the coronal plasma, including its thermodynamical properties.
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The paper presents the statistical data analysis of radio astronomic surveys in the sky region of a size of 177▭° at high galactic latitudes. We divided the region into four sectors equal in area and analyzed the observed properties of radio sources and the cosmic microwave background in each sector.
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We continue the monitoring of microquasar GRS 1915+105 at 2.3, 4.8, 8.2, 11.2 and 22.3 GHz with the RATAN-600 radio telescope (see also ATEL #1509, #2899).
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The results of observations of the blazar J1504+1029 (PKS 1502+106, OR 103), obtained in 2000-2018 on the RATAN-600 radio telescope of the Special Astrophysical Observatory at 2.3, 3.9 (4.7), 7.7 (8.2), 11.2, and 21.7 GHz and on the 32-m Zelenchuk and Badary radio telescopes of the Quasar-KVO complex of the Institute of Applied Astronomy of the Russian Academy of Sciences at 5.05 and 8.63 GHz are presented.
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We present model fits to the X-ray line spectrum of the well-known high-mass X-ray binary Cyg X-3. The primary observational data set is a spectrum taken with the Chandra X-ray Observatory High Energy Transmission Grating in 2006, though we compare it to all the other observations of this source taken so far by this instrument.
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