Markarian 478: A Second Seyfert Galaxy with 1 Micron Fe II Emission Lines
Hamann, F.; Rudy, Richard J.; Puetter, R. C.; Lynch, David K.; Mazuk, S.; Venturini, Catherine C.
United States
Abstract
We present infrared spectroscopy of the narrow-line Seyfert 1 galaxy Mrk 478 that shows the 1 μm Fe II lines λ9997, λ10501, λ10863, and λ11126. This is the second active galaxy, after I Zw 1, in which these features have been observed. Like I Zw 1, the 1 μm Fe II lines of Mrk 478 appear to arise from collisional excitation of their common, intermediate-energy, upper term. Under this formation process, these features should be common in active galaxies exhibiting strong ultraviolet and optical Fe II emission but may be obscured in the spectra of the objects with broader lines because of blending with nearby features of hydrogen and helium.