Chip Kobulnicky
UCSC/Lick Observatory
http://zem.ucolick.org/chip


 On the Chemical Properties of Faint Blue Galaxies from z=0.1-0.5.

The history of star formation within individual galaxies and on cosmic
scales is closely coupled to the production of heavy elements.  The
measurement of the metallicity as a function of cosmic epoch is a
consistency check on the star formation rates derived from imaging
surveys.  It is now possible to study the chemical properties of
distant galaxies  through emission line diagnostics which have long
been used in local H II regions.  Initial results from a sample of
compact, narrow emission line galaxies at z=0.2 to z=0.5 show a range
of metallicities from metal-poor like the SMC to super solar.  The
oxygen abundances correlate strongly with optical luminosity just like
local glaxies. This suggests that the chemical production and retention
in individual galaxies is determined prodominantly by local
characteristics, such as the integral star formation history and the
depth of the gravitaional potential rather than the universal star
formation history.  The ratios of specific elements like
nitrogen-to-oxygen can constrain the evolutionary descendants of
hi-z galaxies.