Revisited abundance diagnostics in quasars: Fe II/Mg II ratios

Details Revisited abundance diagnostics in quasars: Fe II/Mg II ratios Revisited abundance diagnostics in quasars: Fe II/Mg II ratios

2003-06-25

arxiv.org/abs/astro-ph/0306533v1

Astrophys.J.592:L59-L62,2003

Astronomy and Astrophysics

Astrophysics

kverner.gzip, 9 pages, f1-5.eps; aastex.cls; aastexug.sty, ApJL in press

Scientific paper

10.1086/377571

Both the Fe II UV emission in the 2000- 3000 A region [Fe II (UV)] and resonance emission line complex of Mg II at 2800 A are prominent features in quasar spectra. The observed Fe II UV/ Mg II emission ratios have been proposed as means to measure the buildup of the Fe abundance relative to that of the alpha-elements C, N, O, Ne and Mg as a function of redshift. The current observed ratios show large scatter and no obvious dependence on redshift. Thus, it remains unresolved whether a dependence on redshift exists and whether the observed Fe II UV/ Mg II ratios represent a real nucleosynthesis diagnostic. We have used our new 830-level model atom for Fe+ in photoionization calculations, reproducing the physical conditions in the broad line regions of quasars. This modeling reveals that interpretations of high values of Fe II UV/ Mg II are sensitive not only to Fe and Mg abundance, but also to other factors such as microturbulence, density, and properties of the radiation field. We find that the Fe II UV/ Mg II ratio combined with Fe II (UV)/ Fe II (Optical) emission ratio, where Fe II (Optical) denotes Fe II emission in 4000 - 6000 A can be used as a reliable nucleosynthesis diagnostic for the Fe/Mg abundance ratios for the physical conditions relevant to the broad-line regions (BLRs) of quasars. This has extreme importance for quasar observations with the Hubble Space Telescope and also with the future James Webb Space Telescope.

Affiliated with

Also associated with

No associations

Rating

Revisited abundance diagnostics in quasars: Fe II/Mg II ratios does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Revisited abundance diagnostics in quasars: Fe II/Mg II ratios, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Revisited abundance diagnostics in quasars: Fe II/Mg II ratios will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-68635