Cosmoview Episode 86: DECam Confirms that Early-Universe Quasar Neighborhoods are Indeed Cluttered

Observations using the Dark Energy Camera (DECam) confirm astronomers’ expectation that early-Universe quasars formed in regions of space densely populated with companion galaxies. DECam’s exceptionally wide field of view and special filters played a crucial role in reaching this conclusion, and the observations reveal why previous studies seeking to characterize the density of early-Universe quasar neighborhoods have yielded conflicting results.