Blue spectropolarimetry of Seyfert 2 galaxies. 1: Analysis and basic results

Spectropolarimetry in the 3200-6200 A range was obtained on 50 Seyfert 2 galaxies. After careful subtraction of a template galaxy, the fractions of the total flux due to starlight F_g_ and to the featureless continuum F_c_ were estimated. All of the Seyfert 2 galaxies have a nonstellar component to their Spectrum. Polarization is not correlated with F_c_ which argues against the hypothesis that all Seyfert 2s have highly polarized featureless continua which are unseen because of dilution by starlight. The nine Seyfert 2s with spectropolarimetrically identified hidden broad-line regions (BLRs) have = 0.30, considerably less than the average of 0.70 found for the larger sample. This suggests that the spectropolarimetric method of identifying hidden BLRs in Seyfert 2s is most sensitive to objects in which the polarization is less contaminated by a large fraction of starlight. The spectropolarimetric data indicate a few additional objects, Mrk 266SW and Mrk 573, which may contain hidden BLRs, but they require further study at Hα.