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 microturbulent 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 nonstationary variables in stellar aggregates.
3. Theory of the transfer of radiation energy.
4. Direct and inverse problems of radiative transfer.
Ashot Akopian
1. Xray flares study.
2. Study of superflares in the solartype 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 
Scientific Publications 20122017

Arthur NIKOGHOSSIAN
 Radiation Diffusion in a Inhomogeneous Turbulent Atmosphere, Astrophysics, 2017, 60, 380392.
 Groups in the Radiative Transfer Theory, J. Quantit. Spectrosc. Radiat. Transfer, 2016, 183, 9099.
 Line Transport in Turbulent Atmospheres, ASP Conference Series, 2016, 511, 221230.
 Some Directions of Development of Theoretical Astrophysics in Byurakan Astrophysical Observatory, Proc. ArmenianIranian Astronomical Workshop, 1316 Oct. 2015, 4655, 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, 1119, (coauthor N.G.Kapanadze).
 Some New Directions of Development of the Radiative Transfer Theory, Astronomy and Astrophysics (Caucasus), 2016, 1, 6880.
 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 2125.
 Groups and their representations in the theory of radiative transfer. II. Astrophysics, 2014, 57, 375383.
 Groups and their representations in the theory of radiative transfer. I. Astrophysics, 2014, 57, 272286.
 New Directions of Development of Astrophysical Radiative Transfer, Proceedings of 5th RussianArmenian Workshop on Math. Phys. Complex. Analysis and Adjacent Problems, 2014, 4648.
 Invariant Imbedding and the Radiation Transfer in a PlaneParallel Inhomogeneous Atmosphere, J. of Astrophys., 2014, ID 193059, 9 pages.
 On the role of the reflection function in describing the diffusion in the planeparallel inhomogeneous atmosphere, Astrophysics, 2013, 56, 553560.
 On Some Trends in the Progress of Astrophysical Radiative Transfer, Light Scazttering Reviews, 2013, 8, 377426.
 The Reflection Properties of Atmosphere as Characteristics of the Radiation Diffusion in it, Proceedings of the ByurakanAbastumani Coll. 2013, pp.1820.
 Solution of linear problems of the theory of radiative transfer in planeparallel atmosphere. III., Astrophysics, 2013, 56, 130141.
 Ambartsumian’ Methods in the Theory of Radiative Transfer, in: Ambartsumian’s Legacy and Active Universe, Springer, 2012, 3759.
 Solution of linear problems of the theory of radiative transfer in planeparallel atmosphere. II., Astrophysics, 2012, 55, 261274.

Hovhannes PIKICHYAN
 Some new results in astrophysical problems of nonlinear theory of radiative transfer, pp., in: “NonStable 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.1923, 2016; ASP Conference Series, 511, Eds: A.M. Mickaelian, H.A. Harutyunian, and E.H. Nikoghosyan; San Francisco, PASP, 2017, 231237.
 On linear properties of the nonlinear problem of radiative transfer, pp. 6572, 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. 2125, 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, 113127.
 Internal radiation field in the nonlinear transfer problem for a onedimensional anisotropic medium. II, Astrophysics, 2016, 59, 272284.
 Internal field of radiation in the nonlinear problem of transfer in onedimensional anisotropic medium. 1, Astrophysics , 2016, 59, 114125.
 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”, 13th annual meeting of Armenian astronomical society, 710 Oct. 2014, Eds. H.A.Harutyunian, A.M.Mickaelian, S.V.Farmanyan, Yerevan, NAS RA, Gituthyun, 2015, 106124.
 Revealing some «linear structure» of solution of the nonlinear problem of radiative transfer in a onedimensional anisotropic medium, in: Proc. of 5th RussianArmenian conference on mathematical physics, complex analysis and adjacent problems, 28 Sept3 Oct, Yerevan. 2014, 4849.
 Determination of the internal field of radiation for a nonlinear problem of the radiation energy transfer, in: Proc. of the ByurakanAbastumani Coll. 2628 August, 2013, Eds: H.Harutyunian, N.Melikian, E.Nikoghisyan; Yerevan, Gituthyun, 2014, 126136.

Ashot AKOPIAN
 Determination of the superflare frequency distribution function of solartype stars, Astrophysics, 2017, 60: 135145.
 An evolved Keplerstar showing substantial flare activity, Astron. Nachr./AN, 2016, 00:1–7 Feb. 2017 (coauthors: M. Kitze, V. Hambaryan, G. Torres, and R. Neuhauser,)
 Variability of superflare frequency of Sunlike stars, Astrophysics, 2015, 58: 6276.
 Frequencies of superflares in solartype stars detected by the Kepler orbital observatory, Astrophysics, 2013; 56: 488500.
 Xrays frequency distribution function of flares of the young stellar objects in the region of ρ Oph, Astrophysics, 2012; 55, 8191.
 Frequency distribution of Xray flares for lowmass young stellar objects in the Orion nebula, Astrophysics, 2012; 55: 505514.