Zobrazeno 1 - 10
of 421
pro vyhledávání: '"Grachev, S. A."'
Publikováno v:
2024, Astrophysical Bulletin, Volume 79, Issue 1, p.159-166
In this paper, the first in a series of four articles, the scientific goals of the Metron project are highlighted, and the characteristics of the cosmic objects available for study within its framework are provided. The Metron interferometer radio te
Externí odkaz:
http://arxiv.org/abs/2311.02323
Publikováno v:
MNRAS 503, 3081 (2021)
We consider a primordial black hole of very high mass, $10^9-10^{10}M_\odot$, surrounded by dark matter and barionic halo at redshifts $z\sim20$ without any local sources of energy release. Such heavy and concentrated objects in the early universe we
Externí odkaz:
http://arxiv.org/abs/2007.10896
Publikováno v:
A&A 619, A29 (2018)
We have considered the formation of the luminescent subordinate HeI lines by the absorption of continuum radiation from a source in the lines of the main HeI series in the expanding Universe. It is suggested that at some moment of time, corresponding
Externí odkaz:
http://arxiv.org/abs/1806.00542
Akademický článek
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Autor:
Dubrovich, V. K., Grachev, S. I.
Within the framework of a flat cosmological model a propagation of an instantaneous burst of isotropic radiation is considered from the moment of its beginning at some initial redshift z0 to the moment of its registration now (at z=0). We take into a
Externí odkaz:
http://arxiv.org/abs/1605.01536
Autor:
Dubrovich, V. K., Grachev, S. I.
Publikováno v:
Astron. Lett., 41, 537 (2015)
Within the framework of a flat cosmological model a propagation of an instantaneous burst of isotropic radiation is considered from the moment of its beginning at some initial redshift z0 to the moment of its registration now (at z=0). Thomson scatte
Externí odkaz:
http://arxiv.org/abs/1602.03695
Autor:
Grachev, S. I., Dubrovich, V. K.
Within the framework of a flat cosmological model a propagation of an instantaneous burst of nonpolarized isotropic radiation is considered from the moment of its beginning at some initial redshift z0 to the moment of its registration now (at z=0). T
Externí odkaz:
http://arxiv.org/abs/1010.4455
Autor:
Grachev, S. I., Dubrovich, V. K.
It is shown that taking into account a recoil for radiation scattering in the Ly-alpha line can lead to a noticable acceleration of primordial hydrogen recombination. Thus for LambdaCDM model a decrease of ionization degree exceeds 1% for redshifts z
Externí odkaz:
http://arxiv.org/abs/0801.3347
Autor:
Nagirner, D. I.1 (AUTHOR) dinagirner@gmail.com, Grachev, S. I.1 (AUTHOR)
Publikováno v:
Astrophysics. Jun2022, Vol. 65 Issue 2, p228-246. 19p.
Autor:
Dubrovich, V. K., Grachev, S. I.
The dependences on z of fractional number densities of H+ and He+ ions are calculated with a proper allowance for two-photon decays of upper levels of hydrogen and parahelium and radiative transfer in intercombination line 2 3P_1 --> 1 1S_0 of helium
Externí odkaz:
http://arxiv.org/abs/astro-ph/0501672