«Gravitational wave kicks monster black hole out of galactic core.» (sciencedaily.com)
No Middle Ground Astronomers know of the giant black holes at galactic cores and the comparatively lightweight versions that form when stars collapse. (scientificamerican.com)
So, instead of relying on this method, Melis» team used radio measurements to perform the work, which opened up a more reliable distance beacon: quasars, amazingly bright galactic cores powered by supermassive black holes. (space.com)