https://phys.org/news/2018-10-high-redshift-quasars-ogle.html

Astronomers are especially interested in finding new high-redshift quasars as they are the most luminous and most distant compact objects in the observable universe. Spectra of such QSOs can be used to estimate the mass of supermassive black holes that constrain the evolution and formation models of quasars. Therefore, high-redshift quasars could serve as a powerful tool to probe the early universe.

Recently, a team of astronomers led by Szymon Kozłowski of Warsaw University Observatory in Poland has conducted a search for high-redshift quasars in Magellanic Clouds. They analyzed the images from OGLE-IV survey and mid-infrared data collected by NASA's Wide-field Infrared Survey Explorer (WISE), which resulted in the detection of 33 quasar candidates.