Theoretical Astrophysics

THE RESEARCH FIELDS

Arthur Nikoghossian

1. Theory of radiative transfer. Groups and their representations in problems of the radiation diffusion in absorbing and scattering atmospheres.
2. Spectral lines formation in turbulent atmospheres.
3. Solar physics. Methods to determining micro-turbulent velocities and kinetic temperature in solar prominences
4. Interpretation of spectra of cosmic objects. The LBV and λ Boo –type stars.

Hovannes Pikichyan

1, Inverse problems of astrophysics.
2. Statistics of the whole number of non-stationary variables in stellar aggregates.
3. Theory of the transfer of radiation energy.
4. Direct and inverse problems of radiative transfer.

Ashot Akopian

1. X-ray flares study.
2. Study of super-flares in the solar-type stars.
3. Young stellar objects with the small mass.

Arthur NIKOGHOSSIAN Dr, of Physical & Mathematical Sciences, professor Head of the Department
Hovhannes PIKICHYAN PhD Senior Research Associate	Ashot AKOPIAN PhD Senior Research Associate

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Scientific Publications 2012-2017

Arthur NIKOGHOSSIAN


• Radiation Diffusion in a Inhomogeneous Turbulent Atmosphere, Astrophysics, 2017, 60, 380-392.


• Groups in the Radiative Transfer Theory, J. Quantit. Spectrosc. Radiat. Transfer, 2016, 183, 90-99.


• Line Transport in Turbulent Atmospheres, ASP Conference Series, 2016, 511, 221-230.


• Some Directions of Development of Theoretical Astrophysics in Byurakan Astrophysical Observatory, Proc. Armenian-Iranian Astronomical Workshop, 13-16 Oct. 2015, 46-55, 2016.


• Line Formation in Turbulent Media, Astronomy and Astrophysics (Caucasus), 2016, 2, 47 -58.


• Adding laws for intensities of radiation outgoing from scattering atmosphere containing energy sources, Astrophysics, 2016, 59, 11-19, (co-author N.G.Kapanadze).


• Some New Directions of Development of the Radiative Transfer Theory, Astronomy and Astrophysics (Caucasus), 2016, 1, 68-80.


• Some New Directions of the Development of the Radiative Transfer Theory, in "Radiation Mechanisms of Astrophysical Objects: Classics Today”, Proc. of the Int. Conf. in honor of the 100th birthday of Acad. V.V.Sobolev, St.Petersburg on September 21-25.


• Groups and their representations in the theory of radiative transfer. II. Astrophysics, 2014, 57, 375-383.


• Groups and their representations in the theory of radiative transfer. I. Astrophysics, 2014, 57, 272-286.


• New Directions of Development of Astrophysical Radiative Transfer, Proceedings of 5-th Russian-Armenian Workshop on Math. Phys. Complex. Analysis and Adjacent Problems, 2014, 46-48.


• Invariant Imbedding and the Radiation Transfer in a Plane-Parallel Inhomogeneous Atmosphere, J. of Astrophys., 2014, ID 193059, 9 pages.


• On the role of the reflection function in describing the diffusion in the plane-parallel inhomogeneous atmosphere, Astrophysics, 2013, 56, 553-560.


• On Some Trends in the Progress of Astrophysical Radiative Transfer, Light Scazttering Reviews, 2013, 8, 377-426.


• The Reflection Properties of Atmosphere as Characteristics of the Radiation Diffusion in it, Proceedings of the Byurakan-Abastumani Coll. 2013, pp.18-20.


• Solution of linear problems of the theory of radiative transfer in plane-parallel atmosphere. III., Astrophysics, 2013, 56, 130-141.


• Ambartsumian’ Methods in the Theory of Radiative Transfer, in: Ambartsumian’s Legacy and Active Universe, Springer, 2012, 37-59.


• Solution of linear problems of the theory of radiative transfer in plane-parallel atmosphere. II., Astrophysics, 2012, 55, 261-274.

Hovhannes PIKICHYAN


• Some new results in astrophysical problems of nonlinear theory of radiative transfer, pp., in: “Non-Stable Universe: Energetic Resources, Activity Phenomena, and Evolutionary Processes”, Proc. of Int. Symp. dedicated to the 70th anniversary of the Byurakan Astrophys. Obs. held by NAS RA, Sept.19-23, 2016; ASP Conference Series, 511, Eds: A.M. Mickaelian, H.A. Harutyunian, and E.H. Nikoghosyan; San Francisco, PASP, 2017, 231-237.


• On linear properties of the nonlinear problem of radiative transfer, pp. 65-72, in: “Radiation mechanisms of astrophysical objects”, Proc. of the conference in honor of the 100th birthday of Acad. V.V. Sobolev held in St. Petersburg, Sept. 21-25, 2015, Eds. by V.P. Grinin, H. Harutyunian, V.B.Il’in, A.F. Kholtigin, A. Nikoghossian, Edit Print, Yerevan, 2017.


• On the linear properties of the nonlinear radiative transfer problem, J. Quantit. Spectroscop. Radiat. Transfer, 2016, 183, 113-127.


• Internal radiation field in the nonlinear transfer problem for a one-dimensional anisotropic medium. II, Astrophysics, 2016, 59, 272-284.


• Internal field of radiation in the nonlinear problem of transfer in one-dimensional anisotropic medium. 1, Astrophysics , 2016, 59, 114-125.


• An application of the cosmologic concepts and astronomical symbols in the ancient medical science and astrology systems, in: “Relation of astronomy to other sciences, culture and society”, 13-th annual meeting of Armenian astronomical society, 7-10 Oct. 2014, Eds. H.A.Harutyunian, A.M.Mickaelian, S.V.Farmanyan, Yerevan, NAS RA, Gituthyun, 2015, 106-124.


• Revealing some «linear structure» of solution of the non-linear problem of radiative transfer in a one-dimensional anisotropic medium, in: Proc. of 5th Russian-Armenian conference on mathematical physics, complex analysis and adjacent problems, 28 Sept-3 Oct, Yerevan. 2014, 48-49.


• Determination of the internal field of radiation for a non-linear problem of the radiation energy transfer, in: Proc. of the Byurakan-Abastumani Coll. 26-28 August, 2013, Eds: H.Harutyunian, N.Melikian, E.Nikoghisyan; Yerevan, Gituthyun, 2014, 126-136.

Ashot AKOPIAN


• Determination of the super-flare frequency distribution function of solar-type stars, Astrophysics, 2017, 60: 135-145.


• An evolved Kepler-star showing substantial flare activity, Astron. Nachr./AN, 2016, 00:1–7 Feb. 2017 (co-authors: M. Kitze, V. Hambaryan, G. Torres, and R. Neuhauser,)


• Variability of super-flare frequency of Sun-like stars, Astrophysics, 2015, 58: 62-76.


• Frequencies of super-flares in solar-type stars detected by the Kepler orbital observatory, Astrophysics, 2013; 56: 488-500.


• X-rays frequency distribution function of flares of the young stellar objects in the region of ρ Oph, Astrophysics, 2012; 55, 81-91.


• Frequency distribution of X-ray flares for low-mass young stellar objects in the Orion nebula, Astrophysics, 2012; 55: 505-514.

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