Chemical Abundance Calibrations for the Narrow-Line-Region of Active Galaxies

Astronomy and Astrophysics – Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

14 pages, 4 figures, accepted for publication in The Astronomical Journal

Scientific paper

10.1086/300242

We investigate two chemical abundance calibrations for the narrow-line-region (NLR) of active galaxies in terms of three easily observable optical emission-line ratios, namely, [OIII]$\lambda\lambda$4959,5007/H$\beta$, [NII]$\lambda\lambda$6548,84/H$\alpha$ and [OII]$\lambda3727/$[OIII]$\lambda\lambda$4959,5007. The calibrations are obtained from a grid of models on the assumption that the main process responsible for the production of these lines is photoionization by a ``typical'' active galactic nucleus continuum. The chemical elements vary their abundance together with oxygen, except nitrogen, which is assumed to be a product of secondary nucleosynthesis. The calibrations are calculated for the range $8.4 \le 12+log(O/H) \le 9.4$, and tested using NLR data for a sample of Seyfert's and LINER's having HII regions in the vicinity of the nucleus. The gaseous abundances of these HII regions have been determined in previous works, and the NLR abundances are obtained on the assumption that they can be extrapolated from those of the HII regions. The calibrations work very well for the Seyfert's, giving abundance values which agree with those obtained from the HII regions, and can thus be used for quick estimates of the chemical abundances of the NLR's. For the LINER's, the calibrations give lower values than those derived from the corresponding HII regions, suggesting that the assumptions of the models do not apply for them, and that there are different physical processes at work in the NLR of the LINER's.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Chemical Abundance Calibrations for the Narrow-Line-Region of Active Galaxies 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 Chemical Abundance Calibrations for the Narrow-Line-Region of Active Galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Chemical Abundance Calibrations for the Narrow-Line-Region of Active Galaxies will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-503515

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.