10648(  1) - 04/05/05 12:16  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      10648
                                                       Version: 1
                                                       Check-in Date: 05-Apr-2005
                                                                      16:16:33

1.Proposal Title:
A Search for the Missing Baryons in Nearby Cosmic Filaments II - Sources of Bias
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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. Renato A. Dupke               University of Michigan
   CoI: Prof. Joel N. Bregman             University of Michigan                        Y
   CoI: Dr. Eric D. Miller                University of Michigan                        N

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6. Abstract

The local "missing baryons" are predicted to be in a warm-hot low density phase,
largely in the giant cosmic filaments that connect the denser virialized clusters
and groups of galaxies. We have recently detected a high fraction of absorption
systems towards the direction that connects galaxy clusters within superclusters,
indicating the presence of the predicted cosmic filaments. The association between
the absoption systems and individual clusters of galaxies is, however, a source of
uncertainty in determining the nature of the detections. Here, we aim at improving
the reliability of previous determination of absoption systems in the line of sight
towards cosmic filaments by establishing a relation between absorption systems and
galaxy cluster "halos". We will look for Ly\alpha absorption lines in the spectra of
a large sample of background AGNs distributed at various projected distances from
clusters of galaxies. This will be used to quantify the likelihood of competing
scenarios to explain the recently detected series of absorption systems in cosmic
filaments.
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                                                10648(  1) - 04/05/05 12:16  - [  2]

            Summary Form for Proposal  10648

  Item                         Used in this proposal
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  Proposal Category            AR
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