Hubble sees double
Grad student Hsiang-Chih Hwang helps refine the technique for identifying quasar pairs, opening the floodgates for the discovery of merging galaxies and revealing more information about galaxy formation and gravitational waves By Rachel Wallach / Published April 28, 2021
Astrophysicists know that just about every large galaxy has a supermassive black hole at its center. They know that when galaxies merge, so, ultimately, do their black holes. But they don t yet know much about how the merging process occurs, or exactly what happens to the supermassive black holes during it.
That s because there haven t been many examples to study. Scientists search for supermassive black holes by looking for quasars, the brilliant objects formed when supermassive black holes feed on bits of matter, which emits copious radiation as it falls into the black hole. Most galaxy mergers happened 10 billion years ago, and when looking tha