7983(  1) - 04/16/98 14:06  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      7983
                                                       Version: 1
                                                       Check-in Date: 16-Apr-1998
                                                                      14:04:11

1.Proposal Title:
The Neutral and High Ionization Gas in 51 Mg II Absorption Systems
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2. Proposal For  3. Cycle
AR               7
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4. Investigators
                                                                                     Contact?
    PI: Chris Churchill                   The Pennsylvania State University
   CoI: Jane Charlton                     The Pennsylvania State University             N
   CoI: Buell Jannuzi                     National Optical Astronomy Observatory        N
   CoI: Sofia Kirakos                     Institute for Advanced Study                  N
   CoI: Charles Steidel                   California Institute of Technology            N
   CoI: Donald Schneider                  The Pennsylvania State University             N

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5. Abstract

We propose to perform a comprehensive study of the ionization and kinematic
conditions of absorbing gas in 51 Mg II absorption systems over the redshift range
0.4 <= z <= 1.4, including 23 newly discovered ``weak'' Mg II absorbers with 0.02 <=
W_ r(2796) <= 0.3 Angstrom. We have obtained high resolution HIRES/Keck spectra and
measured the kinematic component structure of the Mg II (and Fe II) absorbing gas.
For 21 of the systems, we know the associated galaxy's redshift, rest frame B and K
luminosity, color, and QSO-- galaxy impact parameter. Archival FOS G190H and G270
spectra of quasars provide a rich and varied database of absorption lines of neutral
hydrogen (Lyman series and limit), high ionization metals (CIV,[S II]V, N V, and O
VI), and low ionization metals (\CIII, SiII,O I). Combining our existing data on low
ionization gas and galaxy properties with this information from the FOS archive, we
will perform a multivariate correlation analysis. Some key diagnostics are: 1)
kinematic spread of the Mg II profiles vs. overall strength of various high and low
ionization transitions; 2) high ionization vs. low ionization strength as a probe of
collisional vs. photoionization sources; 3) high ionization transition equivalent
widths vs. impact parameter as a test of ionization structure; 4) the ratio of high
to low ionization gas vs. indicators of star formation in galaxies to distinguish
stellar from extragalactic sources. The ultimate goal is to know the chemical
enrichment histories and evolution of ionization structures in galaxies.
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  Data Distribution

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                                                7983(  1) - 04/16/98 14:06  - [  2]

            Summary Form for Proposal  7983

  Item                         Used in this proposal
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  Proposal Category            AR
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