9923(  1) - 04/04/03 10:18  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      9923
                                                       Version: 1
                                                       Check-in Date: 04-Apr-2003
                                                                      10:18:34

1.Proposal Title:
Calculation of Fe II atomic data required for the modeling of HST observations
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2. Proposal For  3. Cycle
AR               11
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4. Investigators
                                                                                     Contact?
    PI: Gary Ferland                      University of Kentucky
   CoI: Prof. Phil Burke                  The Queen's University of Belfast             N
   CoI: Dr. Don Pollacco                  The Queen's University of Belfast             N
   CoI: Prof. Francis Keenan              The Queen's University of Belfast             N

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5. Abstract

Emission lines of singly ionized iron (denoted Fe II) are observed from a wide
variety of astronomical objects. A complete simulation of the physical processes
affecting the Fe II ion would make it possible to deduce the density, temperature,
and iron abundance of the emitting regions. This is a major goal, due to the
ubiquity of Fe II emission, but is difficult because the physics governing Fe II
emission is complex. We have embarked on a long-term project to develop the tools
needed to fully interpret Fe II emission in astrophysical sources. This includes a
complete simulation of the physics of the excitation and transport of Fe II, its
incorporation into our spectral synthesis code CLOUDY, and a comparison of our
calculations with HST and optical spectra of the symbiotic star RR Telescopii. For
this object, the geometry, ionization sources, physical conditions and abundances
are largely understood, and hence it offers an unique astrophysical laboratory to
test and validate the completeness of our CLOUDY numerical simulations. However a
vital requirement of our work is accurate Fe II atomic data, and in particular
theoretical electron collisional excitation rates, as experimental results are not
available for this process. This is the subject of the present proposal.
Specifically, we wish to use our new code PRMAT, designed for accurate calculations
of excitation rates for ions with open d-shells, to produce results for Fe II. We
have already shown that existing atomic data for Fe II are in error. Calculations
with PRMAT will allow Fe II emission lines in astronomical sources to be properly
analysed, and in particular will permit the reliable modeling of UV spectra from
HST.
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                                                9923(  1) - 04/04/03 10:18  - [  2]

            Summary Form for Proposal  9923

  Item                         Used in this proposal
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  Proposal Category            AR
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