Odesa Astronomical Publications

Постійне посилання зібрання

https://dspace.onu.edu.ua/handle/123456789/13200
ISSN 1810-4215
eISSN 2786-5215

Журнал «Одеські астрономічні публікації» публікує наукові статі з питань астрономії, астрофізики, космічних досліджень, а також матеріали конференцій, які організовуються й проводяться за участю НДІ «Астрономічна обсерваторія» Одеського національного університету імені І. І. Мечникова.

Повні тексти видання доступні на сайті Наукової бібліотеки ОНУ імені І. І. Мечникова за посиланням:
https://lib.onu.edu.ua/ukrayinska-odessa-astronomical-publications/

Сайт видання: http://oap.onu.edu.ua/

Переглянути

Перегляд Odesa Astronomical Publications за Автор "Aller, M. F."

Зараз показуємо 1 - 4 з 4
  • Ескіз
    Документ
    ANALYSIS OF THE VARIABILITY AND THE SPECTRUM OF PERIODS OF EXTRAGALACTIC SOURCE OJ 287 IN THE RADIO WAVES
    (Astroprint, 2013) Donskykh, A.; Ryabov, Myhaylo I.; Sukharev, A. L.; Aller, M. F.; Рябов, Михайло Іванович
    We analyzed long-term monitoring of data flux of extragalactic source OJ 287 obtained at frequencies of 14.5 GHz (1974-2011), 8 GHz (1971-2011), 4.8GHz and (1979-2010), on the RT-26, University of Michigan, USA. Variability of the flux of the radio source was investigated by applying wavelet analysis. There were identified long-period (in the range of 3.6 to 13.6 years) and short (in the range from 1.2 to 1.8 years) components at all studied frequencies and it was determined the time of their existence. The "spectra periods" for each year of observation were built to assess the contribution of individual periods in the formation of the most powerful phase of activity of the radio source. The dynamics of the manifestations of active periods at different frequencies was observed. The obtained data was compared with the results of MOJAVE VLBI monitoring for the period of 1995-2012 years at a frequency of 15.4 GHz. It allowed to investigate the structure of emissions during periods of manifestation activity maxima.
  • Ескіз
    Документ
    The study of extragalactic sources 3C 446 AND 3C 345 with using the singular spectrum and wavelet analysis
    (Одеський національний університет імені І. І. Мечникова, 2015) Donskykh, G. I.; Ryabov, Myhaylo I.; Sukharev, A. L.; Aller, M. F.; Рябов, Михайло Іванович
    We investigated the data of monitoring of flux density of extragalactic sources 3С446 and 3C345, which was held on 26-meter radio telescope of University of Michigan at frequencies 14.5, 8 and 4.8 GHz. The data of observations were investigated using singular spectrum analysis and wavelet-analysis. According to the results of wavelet analysis for each year of observations, graphics of “spectra periods” were built to determine the contribution of individual periods in the activity of the radio source. The results obtained with two different methods showed a good correlation between them. For a long time component of the flux the periods of ~ 5 – 9 years were found. For short term components the periods of ~ 1 – 4 years are presented. The results obtained using two different methods were compared with VLBI radio maps, which were obtained by the program MOJAVE. The changes of periods over time are associated with certain physical processes in the system "core – accretion disk – jet" and with appearing of new bright components (knots) in the jet.
  • Ескіз
    Документ
    Using the methods of wavelet analysis and singular spectrum analysis in the study of radio source BL Lac
    (Astroprint, 2014) Donskykh, G. I.; Ryabov, Myhaylo I.; Sukharev, A. L.; Aller, M. F.; Рябов, Михайло Іванович
    We investigated the monitoring data of extragalactic source BL Lac. This monitoring was held with University of Michigan 26-meter radio telescope. To study flux density of extragalactic source BL Lac at frequencies of 14.5, 8 and 4.8 GHz, the wavelet analysis and singular spectrum analysis were used. Calculating the integral wavelet spectra allowed revealing long-term components (~7-8 years) and short-term components (~ 1-4 years) in BL Lac. Studying of VLBI radio maps (by the program Mojave) allowed investigating features of components movement relatively to the VLBI core. The data of radio astronomy observations were also investigated using singular spectrum analysis. This method can solve the task of allocating trend, detection of periodic components and band-pass filtering (reconstruction of time series from quantity of main components, the last corresponds to individual bands of periods on time-frequency spectra or Fourier spectra). Singular spectrum analysis does not use the analyzing function, so its calculations allow to distinguish various components of investigated series with a high accuracy. To get spectral power distribution depending on time in the studied narrowband components obtained by singular spectrum analysis, short-term Fourier transformation was used
  • Ескіз
    Документ
    VARIABILITY OF THE EXTRAGALACTIC RADIO SOURCES 3С120, СТА102, DA55 AND OJ287 ON CENTIMETER WAVES AND ITS CONNECTIONS WITH THE DATA OF VLBI OBSERVATIONS
    (Astroprint, 2012) Ryabov, Myhaylo I.; Donskykh, A.; Sukharev, A. L.; Aller, M. F.; Рябов, Михайло Іванович
    ABSTRACT. By data of the long-term monitoring (30-40 years) fluxes of extragalactic radio sources 3C120, CTA102, DA55 and OJ287 received on the RT-26, University of Michigan present results of data processing with use the wavelet analysis. Received analysis of trend and short-time components of the flux density changes in the studied frequencies 14.5, 8 and 4.8 GHz. For each time components on all frequencies found values of main periods and time of their existence, integrated power spectra for the phases activity for radio sources was built. From the results of VLBI observations in sources with long jets (3C120 and CTA102) detected quasi-periodic structures brighter components. Their appearance is linked to the dynamics of the interaction of shock waves in the jet emission from the cores. Quasi-periodic structures in the jet can be formed as a result of a return standing wave.