NOAO >   Observing Info >   Approved Programs >   2009A-0174

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Proposal Information for 2009A-0174


PI: Ohad Shemmer, Univ. of North Texas, ohad@unt.edu
Address: Dept. of Physics, Denton, Tx, 76203, USA

CoI: Benny Trakhtenbrot, Tel Aviv University
CoI: Scott Anderson, University of Washington
CoI: Niel Brandt, Pennsylvania State University
CoI: Aleksandar Diamond-Stanic, University of Arizona
CoI: Xiaohui Fan, University of Arizona
CoI: Paulina Lira, Universidad de Chile
CoI: Hagai Netzer, Tel Aviv University
CoI: Gordon Richards, Drexel University
CoI: Don Schneider, Pennsylvania State University
CoI: Michael Strauss, Princeton University

Title: Lineless Quasars at High Redshift: Extremely High Accretion Rate Sources?

Abstract: We propose to obtain near-IR spectra of two members of a remarkable class of high-redshift quasars with extremely weak high-ionization emission lines in their UV spectra. Our team has been studying such sources extensively over the past decade, and we find that the weakness of the high-ionization lines is most likely due to extremely high accretion rates. Our proposed near-IR spectra will allow us to test this hypothesis directly by measuring the width of the H_beta emission line, which together with the continuum luminosity, allows a determination of the Eddington ratio. Our spectra will also provide measurements of the [O III] lines with implications for the narrow-line region in these sources. This pilot project will lead to the development of a larger program to determine black-hole masses and accretion rates for a representative sample of these sources. Ultimately, this study may lead to new insights about the accretion process and emission line formation in active galactic nuclei.


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 >   2009A-0174

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