The Frequency of Polarized Broad Emission Lines in Type 2 Seyfert   Galaxies
  We have discovered polarized broad emission lines in five type 2 Seyfert galaxies (NGC 424, NGC 591, NGC 2273, NGC 3081, and NGC 4507), establishing that these objects are type 1 Seyferts obscured by dense circumnuclear material. The galaxies are part of a distance-limited sample of 31 Seyfert 2s, for which spectropolarimetric observations are now complete. Combined with published reports, our results indicate that at least 11 of the galaxies in this sample, or > 35%, possess hidden broad-line regions. This represents the first reliable estimate of the frequency of polarized broad emission lines in type 2 Seyferts, which has important implications for the general applicability of Seyfert unification models. 
E.C. Moran, A.J. Barth, L.E. Kay, A.V. Filippenko