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Session 84 - IGM.
Display session, Friday, January 09
Exhibit Hall,

[84.02] The Relationship Between Galaxies and Low Redshift Weak Lyman Alpha Clouds in the Directions of H 1821+643 and PG 1116+215

T. M. Tripp (Princeton), L. Lu (Caltech), B. D. Savage (U. Wisconsin)

We are conducting a study of the relationship between Lyman alpha clouds and galaxies at low redshifts using the high resolution spectrographs on the Hubble Space Telescope and the multi-object spectrograph on the WIYN telescope. We have obtained high signal-to-noise spectra of two UV-bright QSOs with sufficient sensitivity to detect weak Lyman alpha clouds with rest equivalent widths as low as 50 mA (4sigma), and a third QSO will be observed with STIS in Cycle 7. These clouds are too weak to be detected in spectra obtained by the QSO absorption line Key Project and are apparently less closely tied to galaxies than the stronger Lyman alpha clouds. In support of this HST project, we have measured galaxy redshifts in the 1 degree fields of the QSOs using the WIYN fiber-fed spectrograph. Results of this program for the first two sightlines will be presented.

Program listing for Friday