10969(  1) - 04/03/06 11:15  - [  1]

                  HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 10969

Version: 1    Check-in Time: 03-Apr-2006 15:15:17

Title
An Accurate Determination of the Black Hole Mass vs. Bulge Luminosity Relation for
Nearby AGNs
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Type             Cycle     Parallel Pointing Tolerance
AR               15        <none>
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Investigators
                                                                                     Contact?
    PI: Dr. Chien Y. Peng                 Space Telescope Science Institute
   CoI: Dr. Luis C. Ho                    Carnegie Institution of Washington            N
   CoI: Dr. Aaron J. Barth                University of California - Irvine             N

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Abstract

Supermassive black holes today play a central role in nearly all aspects of
extragalactic astronomy, from AGN physics to galaxy formation and evolution. The
empirical foundation on which much of the recent progress lies came from the tight
correlations found between black hole mass and the properties of the host galaxy,
particularly the luminosity or velocity dispersion of the bulge. Because of the
relative ease with which AGN host galaxies can be measured with HST images, the
black hole mass-bulge luminosity relation provides an effective, powerful tool to
study the coevolution of black holes and their host galaxies, even out to high
redshifts. To this end, it is imperative that we thoroughly understand the local
(low-redshift) black hole mass-bulge luminosity relation. What is its true intrinsic
scatter and zeropoint? Do they depend on the properties of the host galaxy
(morphology, color, environment) or the AGN (level of activity, radio-loudness)? To
explore these issues, we propose to systematically analyze a sample of 142 low-z (<
0.35) broad-line AGNs (Type 1 Seyferts and quasars) that have usable broad-band
images (most have multiple filters) from the HST archives. This sample spans a broad
range in black hole mass, AGN luminosity, Eddington ratio, and degree of radio-
loudness. The images will be analyzed using a powerful new version of the 2-D image
analysis code GALFIT, which can now fit both traditional (bulge, disk, bar) and more
complex substructures (spiral arms, tidal features, lopsidedness, asymmetry). This
ability to fit images in 2-D to high fidelity will permit the most meaningful and
accurate extraction of the bulge component to date, a critical step in calibrating
the local black hole mass-bulge luminosity relation. In addition, the multi-
component decomposition will yield unprecedented information concerning the detailed
morphologies (bulge-to-disk ratios, bars, spiral arms) and local environment of the
host galaxies. The multi-color images will also provide rudimentary, though
important, constraints on the stellar population of the host galaxies, and hence on
the possible connection between AGN activity and star formation.
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