"Astronomers Uncover Massive Protocluster Surrounding Luminous Quasar"

Astronomers have discovered a massive protocluster around a luminous quasar known as J0910–0414, which is one of the most overdense structures known in the early universe. The protocluster, estimated to be three times greater than the nearby Coma cluster, is the most massive one found at a redshift higher than 6.0. This discovery was made possible through observations using the Hyper Suprime-Cam on the Subaru Telescope, the Atacama Large Millimeter/submillimeter Array (ALMA), and other ground-based facilities. The findings suggest that targeting quasar fields with both ALMA and narrow-band observations is an efficient way to identify galaxy overdensities and study the environmental dependence of galaxy evolution.