unknownskywalker:

The wild early lives of today’s most massive galaxies

The LABOCA camera on the ESO-operated 12-metre APEX telescope reveals distant galaxies (marked in red) undergoing the most intense type of star formation activity known, called a starburst. This image shows these distant galaxies, found in a region of sky known as the Extended Chandra Deep Field South, in the constellation of Fornax.

These galaxies are so distant that their light has taken around ten billion years to reach us, so we see them as they were about ten billion years ago. Because of this extreme distance, the infrared light from dust grains heated by starlight is redshifted into longer wavelengths, and the dusty galaxies are therefore best observed in submillimetre wavelengths of light. The galaxies are thus known as submillimetre galaxies.

By studying how some of these distant starburst galaxies are clustered together, astronomers have found that they eventually become so-called giant elliptical galaxies — the most massive galaxies in today’s Universe.

The bright starbursts in these distant galaxies last for a mere 100 million years, yet in this brief time they are able to double the quantity of stars in the galaxies. Astronomers believe that the sudden end to this rapid growth is because the intense starburst also powers the quasar by feeding enormous quantities of material into the supermassive black hole. The quasar in turn emits powerful bursts of energy that blow away the galaxy’s remaining gas — the raw material for new stars — and this effectively shuts down the star formation phase.