ALMA and the First Galaxies

摘要

ALMA will become fully operational in a few years and open a new Window on primordial galaxies. The mm and submm domain is privileged, since the peak of dust emission boss een 60 and 100 microns is redshifted there for z = 5-10, and the continuum benefits from a negative K-correction. At least 100 times more sources than with present instruments could be discovered, so that more normal galaxies, with tosser luminosities than huge starbursts and quasars will be surveyed. The high spatial resolution will suppress the confusion, which plagues single dish bolometer surveys today. Several CO lines detected in broad-hand receivers will determine the redshift of objects too obscured to he seen in the optical. With the present instrumentation. only the most massive and gas rich objects have been detected in CO at high z, most of them being ultra-luminous starbursts with an extremely high star formation efficiency. However, selection biases are omni-present in this domain. and ALMA will statistically clarify the evolution of star formation efficiency, being fully complementary to JWST and ELTs.