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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