NOAO > Observing Info > Approved Programs > 2008A-0280
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NOAO > Observing Info > Approved Programs > 2008A-0280 |
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PI: D. Michael Crenshaw, Georgia State University, crenshaw@chara.gsu.edu
Address: Department of Physics and Astronomy, One Park Place South, SE, Suite 700, Atlanta, GA 30303, USA
CoI: Matthias Dietrich, The Ohio State University
CoI: Margaret Trippe, Georgia State University
Title: Variability of Seyfert Type and the Nature of Seyfert 1.8 and 1.9 Galaxies
Abstract:
The current paradigm for Seyfert 1.8 and 1.9 galaxies is that their
broad Balmer lines are weak as a result of extinction by the atmosphere
of a dusty torus, due to an intermediate-angle view of the broad-line
region (BLR) that is between Seyfert 1 (unobscured) and Seyfert 2
(completely obscured). However, our optical spectra of NGC 2992,
identified in 1980 as a Seyfert 1.9 galaxy, show that it has varied in
apparent type ranging from Seyfert 1 to 2 over the past few decades, due
to large variations in the ionizing continuum flux and subsequent
responses of the BLR to these variations. How many AGN originally
identified as Seyfert 1.8 or 1.9 galaxies are actually unobscured
Seyferts caught in a low flux state? We will obtain new optical spectra
of AGN to answer this question, and to isolate those objects best
explained by the current paradigm for use in our multiwavelength study
of the emission and absorption properties of the torus.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360
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NOAO > Observing Info > Approved Programs > 2008A-0280 |
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