7989(  1) - 04/16/98 14:09  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      7989
                                                       Version: 1
                                                       Check-in Date: 16-Apr-1998
                                                                      14:06:18

1.Proposal Title:
Formation of Bulges: The Role of Nuclear Activity
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2. Proposal For  3. Cycle
AR               7
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4. Investigators
                                                                                     Contact?
    PI: Marcella Carollo                  Johns Hopkins University
   CoI: Tim Heckman                       Johns Hopkins University                      N
   CoI: Colin Norman                      Johns Hopkins University                      N
   CoI: Massimo Stiavelli                 Space Telescope Science Institute             N
   CoI: Tim de Zeeuw                      Leiden University                             N

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5. Abstract

Many physical processes are involved in the formation/evolution of one of the
fundamental building-blocks of the Hubble sequence: the bulges. Detailed
observations support theoretical predictions which attribute an important role to
bar-driven infall of dissipative material toward the galaxy center. Under
appropriate initial/physical conditions, nuclear activity can be a natural component
of the general bulge formation process which fuels the center, and forms new bulge
stellar populations. In turn, the growth and/or fueling of a central engine can
drive strong secular evolution in the host bulges. The goal of our proposal is to
use archival WFPC2/NICMOS photometry for 54 active Sa-Sc galaxies to: (1) determine
the structural properties of their bulges, (2) study the connection between bulge
properties and nuclear structure, and (3) compare the properties of ``active
bulges'' with those of bulges of non-active galaxies of similar luminosities and
Hubble types (available from our previous HST study). Independent efforts are
focussing on searches for circumnuclear structure, e.g., single/nested bars, to
understand the mechanisms that fuel the central engines. These other studies will
not provide the physical properties of the host bulges (e.g., shapes of light-
profiles/isophotes, scale- lengths, nuclear cusps, densities). Our study will fill
this gap by establishing the properties of bulges as a function of activity, and
will pave the road to a clearer understanding of the role of nuclear activity in the
formation/evolution of bulges.
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  Data Distribution

  Media:           ELECTRONIC
  Blocking Factor: 10
  Ship To:         PI_Address
  Ship Via:
  Email:
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                                                7989(  1) - 04/16/98 14:09  - [  2]

            Summary Form for Proposal  7989

  Item                         Used in this proposal
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  Proposal Category            AR
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