Spectroscopy, Spectropolarimetry, and the Featureless Continuum of Seyfert 2 Galaxies
Session 4 -- AGNs
Display presentation, Monday, 9:20-6:30, Pauley Room

## [4.03] Spectroscopy, Spectropolarimetry, and the Featureless Continuum of Seyfert 2 Galaxies

L. Kay (Barnard Coll. and Columbia U.)

Spectropolarimetric observations of Seyfert 2 galaxies have provided compelling evidence that some are in fact Seyfert 1s, viewed at an angle such that the BLR is hidden from direct view. (Tran, Miller, and Kay, 1992, Ap. J., 397, 457, and refs. therein.) However the generalizability of this model to all Seyfert 2 galaxies is still in question. Recently two papers have suggested that these spectropolarimetrically detected hidden BLR Seyfert 2s differ from others in that they have considerably higher radio power (Moran et. al. 1992, A.J., 104, 990) and flatter IR spectra (Hutchings and Neff, 1991, A.J., 101, 434). Using data from a spectropolarimetric study of the featureless continuum of 49 Seyfert 2 galaxies, we looked for differences between hidden BLR Seyfert 2s and the others. The contribution of starlight to the Seyfert 2 spectra was estimated and the starlight was then removed for this analysis. The clearest difference is that the 9 known hidden BLR objects (NGC 1068, NGC 7674, Mrk 3, Mrk 348, Mrk 463E, Was 49b, Mrk 1210, NGC 7212, and Mrk 477) have far lower galaxy fractions than the others. $F_g$ averaged 30\% for the hidden BLR Sy 2s compared to 77\% for the 40 others. This may suggest that the spectropolarimetric method succeeds best when the galaxy fraction is low and the polarization is not diluted by so much starlight.

Radio and IR data from the literature were obtained for 40 of the Seyfert 2s. A 20 cm radio luminosity distribution shows that the hidden BLR objects are at the high end of the distribution, but they are not alone there. The 20 cm radio power is correlated with the optical luminosity of the Seyfert 2s (with the starlight removed) - the hidden BLR objects are among the most luminous in the optical as well. Either spectropolarimetry reveals hidden BLRs best in the more luminous objects, or these Seyfert 2s really are different from the others. The 20 cm radio power is also correlated with $L_{FIR}$. A plot of Log $L_{60\mu}$ vs Log($25\mu/60\mu$) shows that the IR spectra of the hidden BLR Seyfert 2s do tend to be flatter, but they do not comprise a distinct group.