Published in "The Hubble Deep Field", eds. M. Livio,
S.M. Fall and P. Madau 1998
THE PROPERTIES OF LYMAN-BREAK GALAXIES AT REDSHIFT z ~ 3
Mauro Giavalisco
The Observatories of the
Carnegie Institution of Washington,
813 Santa Barbara Street, Pasadena, CA 91101, USA
Abstract. The Lyman-break technique has opened the very
high-redshift universe (e.g., z > 2) to the
empirical investigation. The efficiency of the technique in detecting
very distant star-forming
galaxies has allowed the compilation of large samples at redshifts as
high as z ~ 4.5 with well
controlled selection criteria and homogeneous characteristics. Such data
sets are essential to
explore the spectrum of properties of early galaxies, including spectra,
luminosity function,
morphology, star-formation history, clustering and mass, that are
necessary to constrain the
theories of galaxy formation. Developed for a ground-based survey, the
Lyman-break technique
has been successfully transported to HST observations during the
HDF. Although the HDF
sample of Lyman-break galaxies is very small compared to the
ground-based survey, it is
considerably deeper and covers a larger redshift range. This has allowed
us to study the luminosity
distribution of these galaxies on a large dynamic range and probe their
evolution with redshift.
Here we discuss the salient features of this combined exploration, from
the ground and from
space, of star-forming galaxies during the first
15% of the age of the
universe, emphasizing
how the two surveys have complemented each other to help us unveil the
fundamental traits of
this population. More empirical information will be necessary (at high
as well as intermediate
redshifts) before we can map the Lyman-break galaxies onto systems at
lower redshifts along
an evolutionary sequence with some confidence. However, there is a good
deal of fruitful work
that can be started now by comparing the predictions of cosmological
theories to the properties
of the galaxies that the Lyman-break technique, both in its ground-based
and space-borne incarnation, has allowed us to explore.
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