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Paper: Evolution of the Broad Hα and Hβ Emission-Line Profiles in NGC 5548
Volume: 360, AGN Variability from X-Rays to Radio Waves
Page: 239
Authors: Shapovalova, A.I.; Burenkov, A.N.; Borisov, N.; Vlasyuk, V.V.; Doroshenko, V.T.; Bochkarev, N.G.; Carrasco, L.; Chavushyan, V.H.; Valdes, J.R.; Collin, S.; Dumont, A.-M.
Abstract: We present the results of spectral monitoring of NGC 5548 with the 6-m and 1-m telescopes of SAO (Russia) and at INAOE's 2.1-m telescope of the GHO at Cananea (México). The mean and rms profiles of Hα and Hβ present a double-peaked structure. The relative brightness of the peaks varies. The radial velocity of a red peak decreased from ~ 2500–2600 km s−1 in 2000-2001 to ~ 2100 km s−1 in 2002-2003. There was no apparent correlation between the variations of the radial velocities of this peak and the average continuum flux. The fluxes of the various parts of the line profiles are well correlated with each other and also with the continuum flux. This indicates that the flux variability in different parts of the line profiles on short time scales is caused mainly by the reverberation effect. Our results favor the formation of the broad Balmer lines of NGC 5548 in a turbulent accretion disk with large and moving optically thick inhomogeneities, capable of reprocessing radiation from the central continuum source.
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