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Date and Time of the Query: 2019-06-25 T19:14:13 PDT
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For refcode 1999ApJ...525..673B:
Retrieve 14 NED objects in this reference.
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1999ApJ...525..673B Polarized Broad-Line Emission from Low-Luminosity Active Galactic Nuclei Aaron J. Barth Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138; abarth@cfa.harvard.edu and Alexei V. Filippenko and Edward C. Moran Department of Astronomy, University of California, Berkeley, Berkeley, CA 94720-3411; alex@astro.berkeley.edu, emoran@astro.berkeley.edu Received 1999 March 26; accepted 1999 June 23 ABSTRACT In order to determine whether unified models of active galactic nuclei apply to low-luminosity objects, we have undertaken a spectropolarimetric survey of LINERs and Seyfert nuclei at the Keck Observatory. The 14 objects observed have a median H{alpha} luminosity of 8 x 10^39^ ergs s^-1^, well below the typical value of ~1041 ergs s-1 for Markarian Seyfert nuclei. Polarized broad H{alpha} emission is detected in three LINERs: NGC 315, NGC 1052, and NGC 4261. Each of these is an elliptical galaxy with a double- sided radio jet, and the emission-line polarization in each case is oriented roughly perpendicular to the jet axis, as expected for the obscuring torus model. NGC 4261 and NGC 315 are known to contain dusty circumnuclear disks, which may be the outer extensions of the obscuring tori. The detection of polarized broad-line emission suggests that these objects are nearby, low-luminosity analogs of obscured quasars residing in narrow-line radio galaxies. The nuclear continuum of the low-luminosity Seyfert 1 galaxy NGC 4395 is polarized at p = 0.67%, possibly the result of an electron-scattering region near the nucleus. Continuum polarization is detected in other objects, with a median level of p = 0.36% over 5100 -6100 E, but in most cases this is likely to be the result of transmission through foreground dust. The lack of significant broad-line polarization in most type 1 LINERs is consistent with the hypothesis that we view the broad-line regions of these objects directly, rather than in scattered light. Subject headings: galaxies: active-galaxies: nuclei-galaxies: Seyfert- polarization
Retrieve 14 NED objects in this reference.
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