Mid-Infrared Forbidden Lines In Active Galactic Nuclei: NGC 1068, NGC 4151, and NGC 5506

Session 98 - AGN-Absorption/Emission.
Display session, Thursday, January 16
Metropolitan Ballroom,

[98.04] Mid-Infrared Forbidden Lines In Active Galactic Nuclei: NGC 1068, NGC 4151, and NGC 5506

M. A. Greenhouse (SI/NASM), T. L. Hayward (Cornell U.), S. Satyapal (SI/NASM), D. H. Wooden (NASA/ARC), J. W. Miles (SI/NASM), F. C. Witteborn, J. D. Bregman (NASA/ARC), C. E. Woodward (U. Wyoming), M. A. Malkan (UCLA), J. Fischer (NRL), H. A. Smith (SI/NASM)

We display infrared spectroscopy of three Seyfert galaxies. Velocity resolved spectra covering low excitation potential transitions of [Ar III]8.99 \mum, [S IV]10.54 \mum, and [Ne II]12.81 \mum were obtained using the facility mid-infrared array spectrometer (SpectroCam) of the Palomar Observatory 5 m telescope, and low resolution spectra covering [Mg V]5.61 \mum, [Ar II]6.99 \mum, and [Ne VI]12.81 \mum were obtained using the faint object spectrograph (HIFOGS) of the Kuiper Airborne Observatory.

Our airborne low resolution spectroscopy of NGC 1068 has revealed two new coronal lines of Ne and Mg, and unexpectedly bright [Ar II] emission. Our high resolution ground-based spectroscopy has revealed high contrast [Ar III] and [S IV] in each galaxy, and [Ne II] in NGC 1068 and NGC 4151. The [Ar III], [S IV], and [Ne II] line profiles are highly resolved. In NGC 1068 and NGC 4151, they are fit by single component Gaussians. However, in NGC 5506 evidence for a broad pedestal is seen in the [Ar III] and [S IV] spectra. We find that [Ar III], [S IV], and [Ne II] lines in NGC 1068 exhibit a higher dispersion in line broadening than in NGC 4151, and in both galaxies, we find that the highest transition critical density line we observe ([S IV]) exhibits the narrowest line profile. Comparison of our measured line fluxes to photoionization models of NGC 1068 and NGC 4151 is also presented.

Program listing for Thursday