Mid-IR Properties of an Unbiased AGN Sample of the Local Universe
- Winter, L. M.
- Physical Description:
- 1 electronic document
- Additional Creators:
- Armus, L., Engle, K., Markwardt, C., Berghea, C. T., Muhotzky, R. F., Weaver, K. A., Melendez, M., Dudik, R. P., Kraemer, S., Tueller, J., and Malumuth. E.
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- Unclassified, Unlimited, Publicly available.
Free-to-read Unrestricted online access
- \Ve compare mid-IR emission-lines properties, from high-resolution Spitzer IRS spectra of a statistically-complete hard X-ray (14-195 keV) selected sample of nearby (z < 0.05) AGN detected by the Burst Alert Telescope (BAT) aboard Swift. The luminosity distribution for the mid-infrared emission-lines, [O IV] 25.89 microns, [Ne II] 12.81 microns, [Ne III] 15.56 microns and [Ne V] 14.32 microns, and hard X-ray continuum show no differences between Seyfert 1 and Seyfert 2 populations, although six newly discovered BAT AGNs are shown to be under-luminous in [O IV], most likely the result of dust extinction in the host galaxy. The overall tightness of the mid-infrared correlations and BAT luminosities suggests that the emission lines primarily arise in gas ionized by the AGN. We also compared the mid-IR emission-lines in the BAT AGNs with those from published studies of star-forming galaxies and LINERs. We found that the BAT AGN fall into a distinctive region when comparing the [Ne III]/[Ne II] and the [O IV]/[Ne III] quantities. From this we found that sources that have been previously classified in the mid-infrared/optical as AGN have smaller emission line ratios than those found for the BAT AGNs, suggesting that, in our X-ray selected sample, the AGN represents the main contribution to the observed line emission. Overall, we present a different set of emission line diagnostics to distinguish between AGN and star forming galaxies that can be used as a tool to find new AGN.
- Other Subject(s):
- NASA Technical Reports Server (NTRS) Collection.
- Document ID: 20100015625.
- Copyright, Distribution under U.S. Government purpose rights.
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