NOAO >   Observing Info >   Approved Programs >   2004A-0255

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Proposal Information for 2004A-0255


PI: Craig Warner, University of Florida, warner@astro.ufl.edu
Address: Department of Astronomy, 211 Bryant Space Science Center, Gainesville, FL 32608, USA

CoI: Fred Hamann, University of Florida
CoI: Matthias Dietrich, Georgia St. University

Title: Quasars and Their Host Galaxies at High Redshifts

Abstract: Recent studies indicate that active galactic nuclei (AGNs) with more massive supermassive black holes (SMBHs) reside in more massive host galaxies. However, this relationship between SMBH mass and host galaxy mass/luminosity has so far been established only at low redshifts (z \lesssim 0.5). There is also a relationship between metallicity and galaxy mass/luminosity that is well documented at low redshifts. To study these relationships at high redshifts and make comparisons across cosmic time, we propose spectroscopic 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 AGN metallicity scales with host galaxy mass by making the first direct comparison between these two quantities. We will also combine our results for the high-redshift quasars with a sample of 86 low-redshift AGNs that have existing spectra and host galaxy images to compare critical properties (such as SMBH mass, AGN metallicity, 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 test the relationships between host galaxy magnitude, SMBH mass derived from H(beta), and SMBH mass derived from \ionC4 (lambda) 1549 to calibrate the use of \ionC4 as a mass diagnostic at high-z.


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NOAO >   Observing Info >   Approved Programs >   2004A-0255

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