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R. Worhatch, K. Leighly, C. Finley (University of Oklahoma), J. Moore (University of Wyoming)
The study of the UV \ion{Fe}{2} multiplets in quasar spectra has broad potential applications. In principle, the ratio of \ion{Fe}{2} to \ion{Mg}{2} in high redshift quasars permits a probe of the chemical evolution in the Universe. The complicated multiplets of \ion{Fe}{2} potentially hold information about the excitation and optical depths for low-ionization line emission in the broad-line region. Narrow-line quasars are the best objects to use to study low-ionization line emission, because these lines are frequently strong, and because the narrow lines reduce ambiguity arising from blending.
We report preliminary results for a large catalog of near UV properties of narrow-line quasars from the SDSS DR4. The final catalog is estimated to have ~10,000 objects; a detailed analysis of the first 836 is presented.
Focusing on the region between wavelengths 2200.0Å\/ -- 3050.0Å\/, the first 836 objects were analyzed using the following procedure. First, cosmic rays and galactic absorption lines were removed from the spectra. Then, IRAF {\tt Specfit} was used to fit the spectra with a model including an iron template developed from the HST observation of I~Zw~1. The model consists of 8 components: a powerlaw continuum, the iron template, and 6 gaussians fit to \ion{Mg}{2}~\lambda\lambda 2796.4,2803.5, \ion{Fe}{2} UV 62,63 \lambda 2745.7, \ion{C}{2}]~\lambda 2325.0, and \ion{Fe}{3}~\lambda\lambda 2419.3, 2438.9. This analysis procedure will also be applied to all the remaining objects in the sample.
Ultimately, the catalog will contain the emission line properties (fluxes and equivalent widths, as well as velocity width for \ion{Mg}{2}) and continuum properties (power law index, luminosity), and will be made available to the public.
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.