Supermassive black holes may be surrounded by dark matter clusters, new 'echo map' technique suggests

Astronomers have used a technique called echo mapping to detect hints that supermassive black holes, such as the cosmic titan at the heart of the Milky Way, known as Sagittarius A* (Sgr A*), are surrounded by dense clouds and clusters of dark matter. The research could teach us more about this mysterious substance and the environments around supermassive black holes. Dark matter is the universe's most mysterious stuff, outweighing ordinary matter in the cosmos by a ratio of five to one — but remaining effectively invisible because it doesn't interact with electromagnetic radiation , including the light we use to see. The only way scientists can even infer the presence of dark matter is via its interaction with gravity , and the impact that this interaction has on objects made of traditional matter like stars. For instance, the gravitational effect of dark matter allows stars at the edges of galaxies to whip around at much greater speeds while not flying loose than the visible matter of those galaxies would allow. This team decided to test the gravitational influence of dark matter at the hearts of galaxies, environments dominated by supermassive black holes which can have masses millions or even billions of times that of the sun. Ordinary matter around these supermassive black holes is often very visible, especially when spiraling into the maw of one of these cosmic titans from a flattened cloud called an accretion disk. …