2008/04/07 by M. Meléndez, S. B. Kraemer, Bryan Armentrout +9 · 2 citations
Physics and Astronomy · #Absorption (acoustics) #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Doubly ionized oxygen #Emission spectrum #Extinction (optical mineralogy) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gamma-ray bursts and supernovae #Ionization #Line (geometry) #Luminosity #Optics #Photoionization #Physics #Spectral line #astro-ph
paper · pdf · doi:10.1086/588807
Accepted for publication in the Astrophysical Journal. 31 pages, 6 figures, 4 tables
arxiv created 2008/04/07 · openalex publication_date 2008/07/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We have studied the relationship between the [O IV] 25.89 μm emission-line luminosities, obtained from Spitzer spectra, the X-ray continua in the 2-10 keV band, primarily from ASCA , and the 14-195 keV band obtained with the SWIFT Burst Alert Telescope (BAT), for a sample of nearby ( z < 0.08) Seyfert galaxies. For comparison, we have examined the relationship between the [O III] λ5007, the 2-10 keV, and the 14-195 keV luminosities for the same set of objects. We find that both the [O IV] and [O III] luminosities are well correlated with the BAT luminosities. When comparing [O IV] and [O III] luminosities for the different types of galaxies, we find that the Seyfert 2s have significantly lower [O III] to [O IV] ratios than the Seyfert 1s. We suggest that this is due to more reddening of the narrow-line region (NLR) of the Seyfert 2s, since the [O IV] 25.89 μm emission line is much less affected by extinction. The combined effects of reddening and the X-ray absorption is the probable reason why the [O III] versus 2-10 keV correlation is better than the [O IV] versus 2-10 kev correlation. Based on photoionization models, we find that the [O IV] comes from higher ionization states and lower density regions than previous studies had determined for [O III]. Overall, we find the [O IV] to be an accurate indicator of the power of the AGN.