AAS 197, January 2001
Session 3. QSO Absorbers and the IGM
Display, Monday, January 8, 2001, 9:30am-7:00pm, Exhibit Hall

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[3.06] The Remarkable Mixed Ionization Double Kinematics of a z ~ 1 MgII Absorber

S. G. Zonak, C. W. Churchill, J. C. Charlton, J. Ding (Penn State)

We present an analysis of an unusual redshift z=1.0414 intervening MgII absorber along the line of sight to QSO 1634+706. Combining STIS/HST spectra with HIRES/Keck spectra, high resolution profiles are available for most of the key transitions (Ly-alpha and the Lyman series, MgII, FeII, SiII, CII, SiIII, SiIV, NV and OVI.) These data facilitate a detailed analysis of the kinematic structure of the different phases of gas associated with this system. Four clouds are required to fit this z=1.0414 weak MgII profile. A metallicity (Z~-1.5), constrained by the Lyman limit break, fails to fully account for the broad and saturated Ly-alpha absorption, giving evidence for an additional phase. This additional phase was also needed to fit the CIV profile in a lower resolution FOS spectrum. From the STIS/HST profiles of the Lyman series, CII, SiIII and SiIV, we see clear evidence for this separate higher ionization phases of gas offset by ~150 km/s blueward of the MgII. In the redward component, the SiIV traces the kinematic structure of the MgII indicating an origin in the same clouds. Although not covered in the STIS spectrum, the CIV absorption expected from these clouds is consistent with the earlier FOS/HST spectrum.

This work was supported by and NSF/REU supplement and by the NASA/LTSA program

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The author(s) of this abstract have provided an email address for comments about the abstract: szonak@astro.psu.edu

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