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E. Verner, F. Bruhwheiler (GSFC/NASA & CUA), Y. Tsuzuki, K. Kawara, Y. Yoshii, S. Oyabu (IofA, Tokyo Univ.)
Recently, the number of observational efforts to measure the Fe II /Mg II emission ratios in QSOs has increased, due to their potential to give a clue to understanding of host galaxies and star formation in quasars.
In our first attempt to translate these observational measurements into abundances, we use numerical simulations of Fe II ion and spectra of quasar, PG 1626+554, obtained with the HST/FOS. The Fe II emission contributes to the Mg II doublet which complicates measurement of Fe II(UV)/Mg II emission ratio. We discuss the observational errors in UV and optical parts of PG 1626+554 spectra that affect Fe II flux measurements. Then we demonstrate how to use Fe II (UV) band, Fe II (optical) band and Mg II (UV) doublet fluxes to derive the iron abundance.
We utilize the most sophisticated Fe II ion model (830 levels) to obtain the best fit with observations. As a result of these calculations we estimate iron abundance, hydrogen density and photoionizing flux in quasar environment. Although the result suggests that the iron has solar abundance in the PG 1626+554, more accurate observations are needed to confirm this conclusion.
This work was initiated while EV visit at NAOJ/IoA-UT as a NAOJ COE visiting professor. EV research and travel to AAS is supported by the National Science Foundation (NSF 0206150) program. We acknowledge the set of HST/FOS observations.
The author(s) of this abstract have provided an email address for comments about the abstract: kverner@fe2.gsfc.nasa.gov
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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.