AAS Meeting #193 - Austin, Texas, January 1999
Session 3. Galaxy Evolution and Surveys II - High Redshift
Display, Wednesday, January 6, 1999, 9:20am-6:30pm, Exhibit Hall 1

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[3.04] CIV Absorption and MgII Cloud Kinematics in Galaxies at z~

R.R. Mellon, C.W. Churchill, J.C. Charlton, D.P Schneider (Penn State), B.T. Jannuzi (NOAO), S. Kirhakos (IAS), C.C. Steidel (Caltech)

We have investigated the properties of a sample of 45 MgII absorption selected systems from 0.45We find a very tight correlation between the kinematic spread of MgII (i.e. the velocity range covered by MgII clouds in a given system) and the equivalent width of CIV. This correlation is even tighter than the correlation between the the kinematic spread of MgII and the MgII equivalent width itself, or between the MgII and CIV equivalent widths. In the cases of strong CIV absorption, the higher ionization CIV either arises in a diffuse phase in which the lower ionization MgII is embedded or in gas undergoing bulk/turbulent motions that produce broader CIV profiles. These facts suggest that a higher ionization, possibly turbulent ``CIV halo'' encompasses the MgII gas phase. Individual clouds with Mg II ``cores'' with higher ionization CIV layers are not fully consistent with the observations.

The physical processes governing the production of CIV absorbing gas may give rise to highly ionized galactic-like coronae in early epoch galaxies and also may govern the kinematics of the lower ionization gas. As an example scenario, massive star formation in a galactic disk could propel high velocity clouds and chemically enrich, produce, and sustain extended ``CIV halos''. If such scenarios explain the trends seen in the data, it would imply that the chemical evolution of present day normal galaxies is dominated by the build up of galactic coronae from the inside out.

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

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