CATALOG OF VARIABILITY PERIODS OF EXTRAGALACTIC RADIO SOURCES AT CENTIMETER WAVELENGTHS

• Main Authors: M. I. Ryabov, A. L. Sukharev, H. I. Donskykh
• Format: Article
• Language: English
• Published: National Academy of Sciences of Ukraine, Institute of Radio Astronomy 2016-09-01
• Series: Radio Physics and Radio Astronomy
• Subjects: extragalactic radio sources; quasi-period; variability of radio emission; wavelet analysis; caterpillar-ssa; forecast
• Online Access: http://rpra-journal.org.ua/index.php/ra/article/view/1240/876

Purpose: Study of the variability of flux density of extragalactic radio sources (3C 273, 3C 120, 3C 345, 3C 446, 3C 454.3, OJ 287, OT 081, BL Lac, DA 55, CTA 102) according to a long-term (1965–2011) monitoring at 14.5, 8, 4.8 GHz made with a 26-m telescope of the University of Michigan. Making up a catalog of quasi-periods values and their properties, as well as using this latter to predict the flux changes after 2011 at 14.5 GHz. Design/methodology/approach: Using wavelet analysis, bandpass filtering and singular spectrum analysis (Caterpillar-SSA) the information is obtained on the values and properties of quasiperiods of radio flux density change, separately for the longterm and short-term variability components. Using these values, for the first time the forecasting with the two methods – harmonic and autoregressive linear prediction, has been made. Findings: The catalog of quasi-periodic components of flux density variability is compiled for 10 radio sources, forming dynamics of their activity. The variability of extragalactic radio sources is shown to be formed by adding the quasi-periodic components on different time scales. The results of forecasts showed good compliance with real observations from MOJAVE database. Autoregression method is preferred for a short-term forecasting of flux density changes for radio sources with complex processes of variability. Conclusions: Presented values and properties of quasi-periods are designed to build theoretical models of short-term and longterm variabilities of extragalactic radio sources. The ability to predict changes in flux density of extragalactic radio sources using their variability data enables efficient planning of observation programs.