10688(  1) - 04/05/05 12:39  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      10688
                                                       Version: 1
                                                       Check-in Date: 05-Apr-2005
                                                                      16:39:03

1.Proposal Title:
High resolution simulations of the low redshift intergalactic medium
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2. Proposal For  3. Cycle  4. Parallel Pointing Tolerance
AR               14        <none>
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5. Investigators
                                                                                     Contact?
    PI: Dr. David R. Tytler               University of California - San Diego
   CoI: Dr. David Kirkman                 University of California - San Diego          N
   CoI: Dr. Michael L. Norman             University of California - San Diego          N

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6. Abstract

We propose to use the hydrodynamic code Enzo to run the first adaptive mesh
refinement (AMR) simulations of the Lyman alpha forest to z=0 that have the size,
resolution and parameter values to permit precise quantitative comparison with
redshifted H I absorption lines in hundreds of HST QSO spectra from FOS, GHRS, and
STIS. We will explicitly explore the effects of the intensity of the ionizing
radiation (UVB) and the amplitude of the matter power spectrum. We will derive
scaling relations between the simulation input and the statistics of the output
Lyman alpha forest, which we will use to estimate the parameters that best match the
Lyman-alpha forest in HST spectra. We expect two immediate results. First, we will
discover whether popular values for cosmological parameters and UVB provide a
precise description of the Lyman-alpha forest at z < 1.6. Second, we will make more
accurate measurements of the evolution of the intensity of the UVB. The simulations
will be useful for a wide variety of studies of the redshifted absorption in QSO
spectra, such as the distribution of metals including O~VI absorption that traces
the warm-hot intergalactic medium. We will make the simulated absorption spectra and
the raw simulation box data available to the community through our site
http://www.cosmos.ucsd.edu/~gso/index.html.
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                                                10688(  1) - 04/05/05 12:39  - [  2]

            Summary Form for Proposal  10688

  Item                         Used in this proposal
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  Proposal Category            AR
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