NOAO >   Observing Info >   Approved Programs >   2008A-0280

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Proposal Information for 2008A-0280


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



NOAO >   Observing Info >   Approved Programs >   2008A-0280

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