NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-04-18 T04:01:46 PDT
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For refcode 2010ApJ...725.1749T:
Retrieve 34 NED objects in this reference.
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Copyright by American Astronomical Society. Reproduced by permission
2010ApJ...725.1749T A Multi-wavelength Study of the Nature of Type 1.8/1.9 Seyfert Galaxies Trippe, M. L.; Crenshaw, D. M.; Deo, R. P.; Dietrich, M.; Kraemer, S. B.; Rafter, S. E.; Turner, T. J. Abstract. We focus on determining the underlying physical cause of a Seyfert galaxy's appearance as type 1.8 or 1.9. Are these "intermediate" Seyfert types typical Seyfert 1 nuclei with reddened broad-line regions? Or are they objects with intrinsically weak continua and broad emission lines? We compare measurements of the optical reddening of the narrow and broad-line regions with each other and with the X-ray column derived from XMM-Newton 0.5-10 keV spectra to determine the presence and location of dust in the line of sight. We also searched the literature to see if the objects showed evidence for broad-line variability, and determined if the changes were consistent with a change in reddening or a change in the intrinsic ionizing continuum flux. We find that 10 of 19 objects previously classified as Seyfert 1.8/1.9s received this designation due to their low continuum flux. In four objects, the classification was due to broad emission-line region reddening, either by the torus or dust structures in the vicinity of the narrow emission-line region; in the remaining five objects there is not sufficient evidence to favor one scenario over the other. These findings imply that, in general, samples of 1.8/1.9s are not suitable for use in studies of gas and dust in the central torus. Key words: galaxies: active, galaxies: Seyfert, infrared: galaxies, X-rays: galaxies
Retrieve 34 NED objects in this reference.
Please click here for ADS abstract

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