SCATTERING AND ABSORPTION IN SOFT-X-RAY SELECTED AGN - AN OPTICAL POLARIZATION SURVEY

We have surveyed the optical linear polarization of a completely ident ified sample of 43 bright soft-X-ray-selected ROSAT AGN. Most (40) of these AGN show low polarization (less than or equal to 1%), and no cle ar optical reddening. This supports the suggestion from rapid X-ray va riability, disk-like spectral energy distributions, and lack of cold X -ray absorption, that we are viewing a bare AGN disk. IRAS F12397+3333 and IRAS 13349+2438 show high polarization increasing to the UV - cle ar evidence for scattering. As well as steep, soft-X-ray spectra, they show optical reddening and rapid X-ray variability, but almost no col d X-ray absorption - a combination that suggests dusty ionized gas alo ng the line-of-sight. Brandt et al. suggested and found these 'warn ab sorbers' for IRAS 13349+2438. IRAS F12397+3333 is a new candidate. Com bining our data with the optical and X-ray spectra of the high polariz ation narrow-line Seyfert 1 nuclei (NLSy 1s) investigated by Goodrich reveals strong correlations among optical reddening indicators (alpha( opt) and H alpha/H beta), [O III]/H beta(b), and cold intrinsic X-ray absorption Delta N-H. Optical reddening underpredicts the cold X-ray a bsorption, suggesting dusty warm absorbers in all the highly polarized AGN. The existence of these scattering-polarized and reddened NLSy 1s suggests an orientation Unified Scheme within the class of NLSy 1s, a nalogous to that linking Seyfert 1 and Seyfert 2 nuclei. For some high ly polarized and optically selected AGN we present new analysis of arc hival X-ray data, and for the highly polarized AGN new optical spectro scopy is presented in an appendix.