NOAO >   Observing Info >   Approved Programs >   2005A-0482

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Proposal Information for 2005A-0482


PI: Fred Hamann, University of Florida, hamann@astro.ufl.edu
Address: Department of Astronomy, 211 Bryant Space Science Center, Gainesville, USA

CoI: Craig Warner, University of Florida
CoI: Matthias Dietrich, Ohio State University
CoI: Linda Watson, University of Florida

Title: Quasars and Their Host Galaxies at High Redshifts

Abstract: Recent studies indicate that more massive supermassive black holes (SMBHs) reside in more massive host galaxies. There is also a well- established positive correlation between galaxy mass and galaxy metallicity. However, both of these relationships have so far been studied only at low redshifts. To examine these relationships at high redshifts and make comparisons across cosmic time, we propose spectroscopic emission-line observations of AGNs at both low (z \lesssim 0.5) and high (z \gtrsim 1.8) redshifts that have \it published imaging data of their host galaxies. Our observations will test the hypothesis that the gas-phase metallicities near AGNs also scale with host galaxy mass by making the first direct comparison between these two quantities. Our observations will also provide a critical complement to existing HST (near-UV) spectroscopy of low- redshift AGNs, also with published host galaxy images. The combined dataset will allow us to compare critical AGN properties (such as metallicity, SMBH mass, and the accretion diagnostic L/L_edd) in samples having similar AGN or host galaxy luminosities at different cosmic epochs. Since the high-redshift sample corresponds to a cosmic time ~ 7 Gyr earlier than the low-redshift sample, this is an important test of coupled AGN/galaxy evolution. Finally, we will compare the SMBH masses derived from H(beta) and \ionC4 (lambda) 1549, and compare both the the host galaxy luminosities, to calibrate the use of \ionC4 as a mass diagnostic at high-z.


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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