Other
Scientific paper
Jan 1993
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993phdt........31t&link_type=abstract
Thesis (PH.D.)--UNIVERSITY OF CALIFORNIA, SANTA CRUZ, 1993.Source: Dissertation Abstracts International, Volume: 54-10, Section
Other
6
Lick Observatory
Scientific paper
We present high signal-to-noise ratio spectropolarimetric observations of ten Seyfert 2 galaxies currently known to harbor obscured broad-line regions (BLRs). The data, which cover the spectral range lambdalambda 3200-7400 at moderate resolution, were obtained with the Shane 3-m telescope at Lick Observatory. Based on the high, time-independent degrees of polarization, the wavelength dependence of the polarization and position angle after correction for effects of interstellar polarization and dilution by host galaxy starlight, the comparison of the spectral shapes between the total integrated and polarized flux spectra, and other supporting X-ray observations, we conclude that electron scattering is the dominant mechanism responsible for the nuclear polarizations in 9 of the 10 galaxies in the sample, although a substantial contribution from dust scattering and/or transmission is likely in at least 4 objects. In only one case, NGC 7674, does the evidence suggest that dust scattering is the dominant cause of the observed nuclear polarization. The corrected continuum polarizations display, in all galaxies but NGC 1068, a rise in the amount of polarization in the broad wings of Hβ and H alpha, while the polarization position angle remains more or less the same between the broad-line wings and continuum. In a majority of the objects, the polarization electric vectors are essentially perpendicular to the radio structure axis and/or the position angle of the extended ionization cones or jets. The polarized broad lines tend to be redshifted relative to the galactic nucleus. These observational results strongly suggest that the obscuring torus picture with the general scattering geometry proposed for NGC 1068 is basically correct, but in addition to the scattered (hence polarized) continuum radiation, there must exist a substantial unpolarized component F c2 underlying the total observed continua of these Seyfert 2 galaxies. The continuum polarizations after the removal of this diluting component are generally very high (_sp{~}>15%), and in accord with those expected from the obscuring torus/scattering electron model. Available evidence also suggests that Fc2 may represent the optically thin thermal radiation from the scattering region itself. Barring strong selection effects, polarized BLRs appear to be found predominantly in multiple, perhaps interacting systems of galaxies, indicating that perturbing or merging processes may play an important role in the existence and/or detection of hidden BLRs in Seyfert 2 galaxies at some stages of their evolution.
No associations
LandOfFree
Spectropolarimetry of Seyfert 2 Galaxies with Obscured Broad-Line Regions does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Spectropolarimetry of Seyfert 2 Galaxies with Obscured Broad-Line Regions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spectropolarimetry of Seyfert 2 Galaxies with Obscured Broad-Line Regions will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1264327