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Reconstructing the 3D structure of the gas and dust region Sh-S235
A new method is proposed for studying the spatial structure of the gas and dust
clouds surrounding galactic regions of ionized hydrogen. An analysis of the
brightness distribution in optical emission lines obtained using a photometer
with an adjustable MaNGaL filter mounted on the 1-meter telescope of SAO RAS
allowed us to plot electron density and dust extinction distribution maps for
the Sh-S235 galactic nebula. A comparison of these data with the infrared AKARI
satellite observations allowed us to understand the spatial distribution of
the neutral matter around the ionized «bubble» surrounding the young hot star:
the far wall turned out to be significantly more dense than the closer wall.
This method is proposed to be used to study the spatial structure of other
nearby star-forming regions.
Authors:
Moiseev A.V., Uklein R.I. (SAO RAS) together with Kirsanova M.S., Boley P.A., Wiebe D.S. (INASAN, MIPT)
Published:
1. M.S. Kirsanova, P.A. Boley, A.V. Moiseev, D.S. Wiebe, R.I. Uklein, 3D structure of
HII region Sh2-235 from tunable filter optical observations, 2020, MNRAS, 497, 1050
A new method of measuring the dust sublimation radius in active galactic nuclei
based on broad line polarimetry
A new method was developed for determining the inner radius of the dust torus
surrounding the central regions of active galactic nuclei (AGN), based on
the reverberation mapping of broad emission lines in polarized light.
Equatorial scatter on the dust torus is observed in type-1 AGNs, which
manifests itself in specific peculiarities in the profiles of broad lines
in polarized light. A time lag between the non-polarized continuum flux and
the polarized line determines the distance to the scattering region, where
the medium becomes optically thick and the temperature is sufficiently low
for the formation of dust. The method was first used on a Seyfert galaxy Mrk 6,
whose spectra and polarimetry were observed in 2010-2013 with SCORPIO-2 mounted
on the BTA. The sublimation radius amounted to ~100 light days (0.0002 seconds
of arc), which refined the size of the scattering region by a factor of 2
compared to the estimates from IR-interferometry data obtained with the
Keck telescopes.
Authors:
Shablovinskaya E.S., Afanasiev V.L.:
(SAO RAS) in cooperation with Popovic L.
(Astronomical observatory Belgrade, Serbia)
Published:
1. Shablovinskaya E.S., Afanasiev V.L., Popovic L.C., Measuring the
AGN Sublimation Radius with a New Approach: Reverberation Mapping
of Broad Line Polarization, 2020, ApJ, 892, 118. doi:10.3847/1538-4357/ab7849
Cosmic microwave background (CMB) studies
GLESP, a program-algorithm package widely used by many cosmologists in Russia and abroad,
was developed based on original methods of analysis of the results of cosmological
experiments WMAP (NASA) and Planck (ESA). Over 10 years, the following was implemented:
a new effective method of radio map pixelation on a full sphere, an analysis of the
CMB fluctuation power spectrum for various methods of accounting for background
radiation in the Galaxy, a mathematical apparatus for studying the statistical
properties of CMB fluctuations.
The use of GLESP, for the first time in Russia, allowed the author to analyze in detail
the essential results of modern observational cosmology and the future key radio
astronomical experiments. Four scientific surveys were published over the course
of this work, dedicated to the properties of CMB and the decisive contribution of
such studies to the development of the current cosmological model.
Authors:
Verkhodanov O.V. (SAO RAS)
Published:
1. O.V. Verkhodanov, Searching for non-Gaussianity in observational cosmic
microwave background data. Physics Uspekhi, Volume 55, Issue 11, pp. 1098-1114 (2012)
2. O.V. Verkhodanov, A.G. Doroshkevich, Sky pixelization for the analysis of extended emission.
Physics Uspekhi, Volume 56, Issue 8, article id. 801-812 (2013)
3. O.V. Verkhodanov, Cosmological results from the Planck space mission and their comparison
with data from the WMAP and BICEP2 experiments. Physics Uspekhi, Volume 59, Issue 1, pp. 3-41 (2016)
4. Verkhodanov O.V., Relic Radiation and the Modern Cosmological Model,
Astronomy Reports, 2021, Vol. 65, N. 3., P. 153-169.
High-energy neutrinos are born in radio-bright blazars
Finding the sources of astrophysical neutrinos and studying mechanisms of their formation
is of utmost importance for our understanding of high-energy processes in the Universe,
including the acceleration of relativistic protons. Using the data from the IceCube neutrino
telescope, observations carried out using international radio interferometric networks as
well as RATAN-600 of SAO RAS, we discovered that neutrinos in a wide spectrum of energies
are born in the central regions of bright blazars, i.e., active galaxies with jets directed
toward the observer. We show that the regions of arrival of super high-energy neutrinos
(from TeV to PeV) coincide with the positions of bright quasars in the sky, and the moments
of arrival - with powerful bursts of synchrotron radiation in the compact jets of these objects.
The obtained results will allow us to better understand the properties of the AGN central
machines as accelerators of massive particles (protons).
The result was obtained in cooperation with ASC LPI RAS, INR RAS and MIPT.
Authors:
Sotnikova Yu. V., Erkenov A.K., Nizhelsky N.A., Tsybulev P.G., Zhekanis G.V., Bursov N.N.
(SAO RAS) together with Kovalev Y.A, Kovalev Y.Y, Sokolovsky K.V., Voitsik P.A.,
Popkov A.V. (ASC LPI RAS), Plavin A.V. (MIPT), Troitsky S.V. (INR RAS)
Published:
1. Yu.A. Kovalev, N.S. Kardashev, Y.Y. Kovalev, K.V. Sokolovsky,
P.A. Voitsik, P.G. Edwards, A.V. Popkov, G.V. Zhekanis, Yu.V. Sotnikova,
N.A. Nizhelsky, P.G. Tsybulev, A.K. Erkenov, N.N. Bursov,
"RATAN-600 and RadioAstron reveal the neutrino-associated blazar
TXS 0506+056 as a typical variable AGN"; Advances in Space Research, 2020,
vol. 65, issue 2, p. 745-755
2. A. Plavin, Yu.Y. Kovalev, Yu.A. Kovalev, S. Troitsky; "Observational
Evidence for the Origin of High-energy Neutrinos in Parsec-scale Nuclei
of Radio-bright Active Galaxies"; The Astrophysical Journal, 2020, vol. 894,
issue 2, id. 101 p. 13
3. Yu.A. Kovalev, Yu.V. Sotnikova, A.K. Erkenov, Y.Y. Kovalev, A.V. Plavin,
S.V. Troitsky; "The RATAN-600 2-22 GHz continuum spectrum of the neutrino
association quasar TXS 1100+122 is slightly rising"; The Astronomer's
Telegram, 2020, No. 13405,
https://www.astronomerstelegram.org/?read=13405
4. Y.Y. Kovalev, S.V. Troitsky, Yu.A. Kovalev, A.V. Plavin; "Flat spectrum
radio quasar TXS 1100+122 has a bright VLBI-compact core - as expected
for neutrino candidate sources"; The Astronomer's Telegram, 2020, No.13397,
https://www.astronomerstelegram.org/?read=13397
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