The structure of the Akn 120 emitting region: The line shapes and long-term H-beta line profile variation

To investigate the structure of tile Akn 120 emitting region we have analys ed the spectral line profiles of H-alpha, H-beta, Ly(alpha), C III[1909], C IV[1549] and Mg II[2798] lines using a Gaussian decomposition approach. Th e decomposed shape of the Akn 120 lines indicates three separated broad lin e-emitting regions, in two of them, the systematic motions of emitting gas are present. It seems that one of the two regions has a high random velocit y of emitters (approximate to 2500 km s(-1)) and approaching line-of-sight velocities, and the other has a smaller random velocity of emitters (approx imate to 1000 km s(-1)) and receding line-of-sight velocities. Also, we dis cuss the long-term H-beta line shape variation in the spectra of Akn 120. T he H-beta line (from 96 spectra) was fitted with three broad and one narrow Gaussians through the entire period considered (1977-1990). The central br oad as well as blue component of H-beta and shelf (Fe II template) cause th e H-beta line shape variation. Besides the Gaussian decomposition of the sh apes of the three hydrogen lines we propose here a disk model with two more regions located symetrically to the disk plane. Using the fitting: method with the disk model we obtained the parameters of the disk: i = 10 degrees; R-inn approximate to 120-200 R-g, R-out approximate to 1000 R-g.