Further Steps Toward Understanding Galaxy Evolution

Mauro Giavalisco
UMass

I will discuss recent results from a suite of new observations
targeting high-redshift galaxies identified during the Great
Observatories Origins Deep Survey (GOODS). These include follow-up
spectroscopy of Lyman-Break galaxies at redshift 4<z<6, which yielded
the largest sample of spectra at z~6, shed light on the variety of
their spectroscopic properties, and provided the first validation of
the photometrically selected samples at such early epochs. It also
include samples of galaxies at z~3, selected from their rest-frame
optical/UV colors in a way that is largely independent on dust
reddening. These samples include galaxies with substantially larger
stellar mass and star-formation rate than Lyman-break galaxies at the
same redshifts and contribute a larger fraction to the cosmic
star-formation rate density. They also include essentially
passively-evolving sources. I will also discuss deep mapping at
millimeter-wavelength of the GOODS fields, which are providing
independent information on the star-formation activity of some of the
galaxies, as well as helping understand the nature of the recently
discovered powerful Compton-think AGN buried in star-forming galaxies
at redshifts z~2. Finally, I will also touch on the lessons learned by
studying the spatial clustering of star-forming galaxies at high
redshift.