COSMOS2020: Discovery of a Protocluster of Massive Quiescent Galaxies at z = 2.77
COSMOS2020: Discovery of a Protocluster of Massive Quiescent Galaxies at z = 2.77
Protoclusters of galaxies have been found in the last quarter century. However, most of them have been found through the overdensity of star-forming galaxies, and there had been no known structures identified by multiple spectroscopically confirmed quiescent galaxies at $z>2.5$. In this letter, we report the discovery of an overdense …