Classification by Activity Type of a Sample of Active Galaxies with Radio Emission
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CLASSIFICATION BY ACTIVITY TYPE OF A SAMPLE OF ACTIVE GALAXIES WITH RADIO EMISSION
H. V. Abrahamyan, A. M. Mickaelian, G. M. Paronyan, and G. A. Mikayelyan
This is a detailed spectral classification of 96 active galaxies from the Véron-Cetty and Véron catalog (2010, Version 13, VCV-13) of active galaxies and quasars. These objects were identified as radio sources using standard radio catalogs. Those galaxies which had radio sources in at least 6 different radio bands and had been identified spectrally in the SDSS catalog were selected. The types of activity of these were determined using their SDSS spectra. Three diagnostic diagrams and a direct study of the spectra were used for more certain classification. As a result, the classifications of 85% of the objects were changed. The radio sources in different radio bands make it possible to construct the spectral distribution of the energy in the radio range and to compare it with the optical activity types. Keywords: galaxies: active galactic nuclei: radio galaxies: spectral classification
1. Introduction
This paper is devoted to a detailed spectral classification of 96 active galaxies. The Véron-Cetty and Véron catalog (referred to below as VCV-13) [1] is used to select the objects for study. This catalog contains 34231 active galaxies. Of them, 23258 are Seyfert type galaxies, 907 are LINERs, 167 are HII, and 9899 do not have a spectral classification.
V. Ambartsumyan Byurakan Astrophysical Observatory (BAO), National Academy of Sciences of the Republic of Armenia, Armenia; e-mail: [email protected]
Original article submitted January 24 2020; accepted for publication June 24 2020. Translated from Astrofizika, Vol. 63, No. 3, pp. 363-374 (August 2020) 322
0571-7256/19/6303-0322 ©2020 Springer Science+Business Media, LLC
Active galaxies are some of the most interesting objects in the universe. They have higher luminosity than ordinary galaxies. It is important that active galaxies have brighter nuclei than normal galaxies. In these galaxies a large amount of energy is radiated from their nuclei. It is assumed that the center of each of these galaxies contains a massive or supermassive black hole (SMBH). Some active galaxies have giant jets in the radio and optical ranges, mainly in the radio bands. Active galaxies come in different types: radio galaxies, Seyfert galaxies (Sy), quasars (QSO), blasars (BL), LINERs, etc. Radio galaxies are elliptical galaxies. All galaxies emit some amount of energy as radio waves, but for normal galaxies the radio emission corresponds to a small fraction of the total energy radiated by the galaxy. In this paper the main selection criterion was taken to be the radio emission of the galaxies. This was done through cross-correlation with the following catalogs: FIRST, NVSS, 87GB, GB6, 3C, 4C, 7C, 8C, 9C, 10C, SUMSS, WISH, WENSS, the Molonglo Reference Catalogue of Radio Sources, the Texas Survey of radio sources at 365 MHz, the Miyun 232 MHz survey, the CLASS survey of radio sources, the 74 MHz VLA Lowfrequency Sky Survey
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