Multidirectional views of the active nucleus of NGC 1068

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view Abstract Citations (250) References (53) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Multidirectional Views of the Active Nucleus of NGC 1068 Miller, J. S. ; Goodrich, R. W. ; Mathews, William G. Abstract Previous spectropolarimetric work has shown that the type 2 Seyfert galaxy NGC 1068 contains a broadline region hidden from our direct view and visible only in scattered, polarized light. New observations, including imaging polarimetry as well as spectropolarimetry, allow us to confirm and extend the earlier work. Off-nucleus regions of high polarization are identified as places in the body of the galaxy where dust reflects light from the hidden broad-line region. This allows for the first time the ability to obtain spectra of an active nucleus as it would appear from several different viewing directions. From these other directions the spectrum of NGC 1068 would appear as a normal Seyfert 1 galaxy. We derive a value of 1.44 x 10^42^ ergs s^-1^ for the Hβ luminosity that would be seen in the absence of obscuration, also typical of Seyfert 1 galaxies. The broad Hβ line as seen reflected in the external dusty regions is significantly narrower than that observed in the nuclear polarized flux, adding additional weight to the view that electron scattering is responsible for the nuclear polarization. The observational data are used to constrain a theoretical model for the electron-scattering region. There is an inherent difficulty in having the same electrons responsible for scattering X-rays and the optical light, since the low electron temperature implied by the scattered broad Hβ line width must be reconciled with the high level of ionization implied by the lack of soft X-ray absorption and the observed energy of the Fe Kα line. However, models satisfying constraints from both optical and X-ray data are possible. We assume a conical electron- scattering region and find that a cone opening half-angle of ~30^deg^ viewed from an angle of 32^deg^ is consistent with the observations, with the inner radius of the scattering region ~10^20^ cm from the nucleus, the electron density ~400-600 cm^-3^, and the mean electron temperature ~(2-3)x10^5^ K. The luminosity necessary to maintain the required ionization level is larger than the observed bolometric luminosity, suggesting the surprising result that the continuum source must be inherently anisotropic. Publication: The Astrophysical Journal Pub Date: September 1991 DOI: 10.1086/170406 Bibcode: 1991ApJ...378...47M Keywords: Active Galactic Nuclei; Astronomical Polarimetry; Seyfert Galaxies; Astronomical Spectroscopy; Charge Coupled Devices; Cosmic Dust; Electron Scattering; Luminosity; Astrophysics; GALAXIES: INDIVIDUAL NGC NUMBER: NGC 1068; GALAXIES: NUCLEI; GALAXIES: SEYFERT; POLARIZATION; SPECTROPHOTOMETRY full text sources ADS | data products SIMBAD (1) NED (1)