NOAO >   Observing Info >   Approved Programs >   2004B-0103

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Proposal Information for 2004B-0103


PI: Matthias Dietrich, Georgia State University, dietrich@chara.gsu.edu
Address: Physics Department, One Park Place South, SE, Suite 700, Atlanta, Georgia 30303, U.S.A.

CoI: D. Michael Crenshaw, Georgia State University
CoI: Steven B. Kraemer, Catholic University of America

Title: Probing the EUV Continuum of Narrow-Line Seyfert 1 Galaxies

Abstract: The ionizing EUV continuum of active galactic nuclei, which is generally associated with thermal accretion disk emission, plays a central role for the physical state of line emitting gas. The strength and shape of the EUV continuum likely depends strongly on the black hole mass and the accretion rate. Galactic absorption prevents direct access to the EUV range, but it can be mapped measuring the strength of a variety of forbidden optical emission lines that respond to different EUV continuum regions. NLS1s are excellently suited to investigate this important continuum range because they show, in contrast to classical Seyfert 1 galaxies, generally strong soft X-ray emission. We propose to observe 15 NLS1s in the optical to measure emission lines with ionization potentials up to ~ 400 eV. Spectra with moderate spectral resolution will be observed to separate the broad and narrow line region (NLR) emission contributions. Detailed photoionization modeling of the NLR will recover the shape and strength of the EUV continuum. Furthermore, we will determine the NLR gas metallicity which is suggested to be higher in NLS1s compared to classical Seyfert 1s.


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 >   2004B-0103

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