The Fe I lines in AGN spectraFe II线AGN光谱in the.pptVIP

The Fe II lines in AGN spectra Jelena Kova?evi?1, Luka ?. Popovi?1 and Milan S. Dimitrijevi?1 1Astronomical Observatory Volgina 7, 11060 Belgrade, Serbia Outline The Fe II lines – what makes them interesting? The sample selection Analysis Results: 1. The Fe II template 2. The ratios of Fe II line groups vs. other spectral properties 3. EW [O III] – EW Fe II anticorrelation and Baldwin effect The Fe II lines – what makes them interesting? The sample selection In order to investigate the Fe II emission lines, we selected the sample of AGN spectra from SDSS DR7, using an SQL search. (/dr6/en/tools/search/sql.asp). The sample selection Analysis We fitted the considered emission spectral lines ([O III], Hβ, [N II], Hα) with summ of Gaussians, Fe II lines are fitted with calculated template, χ2 minimalization routine is used, for obtaining the best fit. Results: 1. The Fe II template To investigate the Fe II emission, we made an Fe II template, taking into account following: (a) majority of Fe II multiplets dominant in λλ4400 -5500 ? range, have one of three specific lower terms of their transitions: 3d6 (3F2)4s 4F, 3d5 4s2 6S or 3d6 (3G)4s 4G (hereinafter F, S and G groups of lines), (b) beside these lines there are also lines whose origin is not well known, and probably originate from higher levels Results: 1. The Fe II template The constructed Fe II template consists of: 35 lines, which describe 75% of Fe II emission in λλ4400 -5500 ? range, and belong to F, S or G group. These line groups approximately correspond to the blue, central and red part of the Fe II shelf. The relative intensities of lines within one line group are calculated using the formula: 15 lines, which probably originate from higher levels, and make about 25% of the Fe II emission. Their relative intensities are taken from I Zw 1 object (I Zw 1 group). Results: 1. The Fe II template The template is described with 7 free pa