Galaxy growth in a massive halo in the first billion years of cosmic history

Understand

According to the current understanding of cosmic structure formation, the precursors of the most massive structures in the Universe began to form shortly after the Big Bang, in regions corresponding to the largest fluctuations in the cosmic density field.

• Observing these structures during their period of active growth and assembly - the first few hundred million years of the Universe - is challenging because it requires surveys that are sensitive enough to detect the distant galaxies that act as signposts for these structures and wide enough to capture the rarest objects.
• As a result, very few such objects have been detected so far.
• Here we report observations of a far-infrared-luminous object at redshift 6.900 (less than 800 Myr after the Big Bang) that was discovered in a wide-field survey.