Large, mature galaxies formed

Surprisingly early. You’d expect that a census of the farthest galaxies that formed earliest in the universe’s history would feature numerous small, hot, young, blue galaxies, perhaps smashing into and coalescing with each other. But the new Gemini Deep Deep Survey (GDDS) shows something very different. The GDDS explored the so-called Redshift Desert, the poorly patrolled region of cosmic history roughly 3–6 billion years after the Big Bang. Galaxies there are redshifted into a spectral region that corresponds to a natural, obscuring glow in Earth’s nighttime atmosphere. Astronomers used a sophisticated technique at the 8-m Gemini North telescope in Hawaii to reveal the feeble spectra of more than 300 galaxies. Survey team member Roberto Abraham (University of Toronto) now speaks of a “Redshift Dessert” with plenty of massive old galaxies where you’d expect few. He and his colleagues reported the results at the January meeting of the American Astronomical Society in Atlanta, Georgia. They found that, in a 4-billion-year-old universe, elliptical galaxies up to 3 billion years old already existed. Furthermore, the galaxies in the survey have many heavy atoms that need to be cooked up in repeated cycles of star birth and supernovae. Abraham says that all of their observations should make theorists sweat. (R. G. Abraham et al. , Astron. J., in press; S. Savaglio et al. , Astrophys. J., in press.)