Editor's Summary

9 October 2008

Inside a young galaxy

Much of what we know about galaxies comes from observations of those that are cosmologically close to us. It is much harder to find out what is going on in the remote star-forming regions of the Universe, where faintness and small angular size mean that only the overall properties of a galaxy are normally observable. But adaptive optics is beginning to bring the interiors of young galaxies, at redshifts equivalent to two to three billion years after the Big Bang, into the observable range. Now by combining adaptive optics with gravitational lensing, where light from a distant galaxy is magnified by the pull of a massive object on the way to Earth, Stark et al. have observed J21352–0102, a typical star-forming galaxy down to a linear resolution of about 100 parsecs. They find a well-ordered compact source in which molecular gas is being converted efficiently into stars, likely to result in a spheroidal bulge similar to those seen in spiral galaxies at the present day.

LetterThe formation and assembly of a typical star-forming galaxy at redshift z approximately 3

Daniel P. Stark, A. Mark Swinbank, Richard S. Ellis, Simon Dye, Ian R. Smail & Johan Richard