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Detection of the Direction of Polarization Vector in the Intraday
Variations of the Source S5 0716+714
In February 2018, we monitored the variations of brightness and polarization
of the bright radio source S5 0716+714 (a BL Lac object) at the 6-m BTA
telescope of SAO RAS. The procedure of observations, implying measurements
of three Stokes parameters (I, Q, and U) of the polarized emission allowed
us to achieve the accuracy of polarimetric measurements better than 0.1%.
The analysis of a number of observations obtained within 9 hours with a time
resolution of about 70 seconds showed the presence of variability of the
integrated brightness and the direction of the polarization vector at times
of about 1.5 hours. Assuming that the optical polarized synchrotron emission of
the jet is generated in a spiral magnetic field at a distance of less than 0.01
parsec from the nucleus, a linear size estimate of the radiating region of the
order of 10 AU was obtained. The numerical simulation of the observed polarization
in the jet also showed the presence of a precessing spiral magnetic field
with a precession period of about 15 days.
Authors:
Shablovinskaya E.S., Afanasiev V.L. (SAO RAS).
Published:
1. E.S. Shablovinskaya, V.L. Afanasiev The intraday variations of polarization vector
direction in radio source S5 0716+714, 2019, MNRAS, Volume 482, Issue 4, p.4322-4328
In detail
Detection of the System of Gaseous Clouds Illuminated by the Active
Nuclei of the Galaxy Mrk 6
We studied the distribution, motions, and state of gas ionization in the
galaxy Mrk6 at the 6-m SAO RAS telescope. In the emission lines of the ionized
gas, extended filaments were found far beyond the galactic disk up to 40 kpc from
the nucleus. Such a gas system is unique among nearby isolated galaxies. All
the obtained data can be explained in the assumption that the observed gas is
captured from the intergalactic medium and illuminated by hard radiation of the
active galactic nucleus. Thus, the active core appeared to be a kind of "searchlight"
which made it possible to directly observe the capture of low-density gas by the
galaxy. Deep images obtained at the 1-m Schmidt telescope of the Byurakan
Astrophysical Observatory of the National Academy of Sciences (Armenia) show
the absence of any star structures (tidal tails, destroyed satellites)
associated with gaseous filaments.
Authors:
Smirnova A.A., Moiseev A.V., Dodonov S.N. (SAO RAS).
Published:
Smirnova A.A., Moiseev A.V., Dodonov S.N., "A close look at the well-known
Seyfert galaxy: extended emission filaments in Mrk 6", 2018, MNRAS, v. 481,
p. 4542.
In detail
Compiling a Catalog of Nearby Voids and Galaxies in them
Voids are elements of the cosmic web visible in the matter distribution.
They occupy more than 75% of the Universe but contain only 15% of its mass.
The observed properties of voids and galaxies inhabiting them are important
for comparison with predictions of formation and evolution of structures in
modern cosmological models. We compiled the first catalog of 25 nearby voids
(at distances of up to 25 Mpc) covering the whole celestial sphere. The
voids with sizes from 14 to 35 Mpc are limited by large galaxies with the
infrared luminosity greater than 20 billion L(solar)_K. We compiled a sample
of 1354 galaxies inhabiting these voids. Their "blue" (B) luminosities fall
in the range of 0.2 million-7 billion L (solar) _B, with a median value of
about 100 million. We found that 1088 objects are "internal" galaxies of voids
with distances to large galaxies of more than 2 Mpc. This sample of void galaxies
is basic for more detailed studies of both the properties of galaxies and the
structure of voids. We described statistical properties of galaxies of nearby
voids including morphology and the proportion of early-type galaxies,
clustering, and gas abundance. We showed the opportunities of the new sample
to search for unusual, youngest galaxies of the nearby Universe.
Authors:
Pustilnik S.A., Tepliakova A.L., Makarov D.I. (SAO RAS).
Published:
1. Pustilnik S.A., Tepliakova A.L., Makarov D.I., «Void galaxies in the nearby Universe.
I. Sample description», 2019, MNRAS, Volume 482, Issue 4, p.4329-4345
In detail
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