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BLR Density Variations of the Seyfert 1 Galaxies NGC 4151 and NGC 5548  

Son, Dong-Hoon (Department of Astronomy and Space Science, Kyunghee Univ.)
Hyung, Siek (School of Science Education (Astronomy), Chungbuk National University)
Publication Information
Journal of the Korean earth science society / v.25, no.6, 2004 , pp. 495-501 More about this Journal
Abstract
Using numerous ground-based or space-based telescopes by many astronomers, AGN spectroscopic monitoring campaigns have been carried out over many years to study the variability of continua and emission lines. We investigate the SWP IUE spectra of a large aperture configuration for the Seyfert 1 galaxies NGC 4151 and NGC 5548. We estimate the BLR electron number densities and their variation from the line ratios of C III] 1909 to Si III] 1892. With the ratios of C IV 1550 to C III] 1909 which give us the information on the ionization parameter of BLR, we try to find the physical conditions of the BLR and activities of he super massive black hole surroundings. The BLR density variations scale as 4 and 8 for NGC 4151 and NGC 5548, respectively. Based on the BLR size and C III] line profiles, we found both black hole masses as about $10^7$ $M_{\odot}$.
Keywords
Seyfert galaxies; active galactic nuclei; ultraviolet spectra; electron density;
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