1999AJ....118..666R

This paper presents spectrophotometric observations from 0.8 to 2.5 µm of the broad emission line radio galaxy 3C 109. Three Paschen lines plus Hα are measured and combined with a published value for Hβ to estimate the reddening for the continuum source and the region producing the broad emission lines. A key factor in this determination is the foreground reddening due to the Galaxy. The recent COBE/IRAS maps of Schlegel, Finkbeiner, & Davis indicate a Galactic extinction of E(B-V)=0.57, more than twice the value inferred from the H I measurements. If the former value is adopted, the in situ reddening is E(B-V)=0.77. This value implies, per the analysis of Goodrich & Cohen, that 3C 109 is an object of extremes, displaying a dereddened UV-optical continuum that is extraordinarily blue (f_ν~ν^1.5) and harboring dust grains that are more efficient polarizers than any found in the Milky Way. Both extremes hint at some additional factor or mechanism, and a few possibilities are discussed. Regardless, the significant amount of internal reddening indicated by infrared spectroscopy is consistent with results from previous optical polarimetry and spectropolarimetry, optical and X-ray spectroscopy, and infrared photometry, in demonstrating that 3C 109 is an obscured quasar–a luminous object whose nuclear radiations from the soft X-ray to the near-infrared are absorbed, scattered, polarized, and reradiated further into the infrared by a circumnuclear envelope of dust.