Zooming in on star-forming galaxies in the early Universe seen with ALMA

This video sequence starts with a broad view of the sky, including the famous constellation of Orion (The Hunter). We gradually close in on an unremarkable patch of sky called the Chandra Deep Field South that has been studied by many telescopes on the ground and in space.

A team of astronomers has used ALMA (the Atacama Large Millimeter/submillimeter Array) to pinpoint the locations of over 100 of the most fertile star-forming galaxies in the early Universe in this part of the sky.

The best map so far of these distant dusty galaxies was made using the Atacama Pathfinder Experiment (APEX), but the observations were not sharp enough to unambiguously identify these galaxies in images at other wavelengths. ALMA needed just two minutes per galaxy to pinpoint each one within a comparatively tiny region 200 times smaller than the broad APEX blobs, and with three times the sensitivity.

At the end of this sequence the fuzzy APEX detections of the galaxies appear first, followed by the much sharper ALMA images that pin down the emitting galaxies much more precisely. The ALMA and APEX observations, at submillimetre wavelengths, are overlaid on an infrared view of the region as seen by the IRAC camera on the Spitzer Space Telescope (coloured blue).