No Doughnut | by Brian Koberlein



27 Could 2014

Galaxies clumped together in the Fornax cluster.
Galaxies clumped collectively within the Fornax cluster.

Inside most galaxies is a supermassive black gap. These black holes can have a mass of tens of millions and even billions of Suns. When actively consuming materials, these black holes can produce great quantities of power, and could be seen as quasars, blazars and radio galaxies, relying upon the best way they’re oriented relative to our vantage level. Not less than that’s been our understanding. However now a brand new paper within the Astrophysical Journal has thrown a wrench in a single a part of that concept.

The paper appears on the variations between obscured and unobscured black holes. With some supermassive black holes, the area close to the black gap is comparatively freed from fuel and mud (unobscured) and thus is pretty vivid. With others, the black gap is surrounded by fuel and mud (obscured) and thus the area close to it’s pretty darkish.

In the doughnut model, black holes are obscured or unobscured based upon their orientation.
Within the doughnut mannequin, black holes are obscured or unobscured based mostly upon their orientation.

Within the unified mannequin, it’s usually thought {that a} black gap is surrounded by a torus of fabric, gathered by way of gravitational and electromagnetic interplay with close by fuel and mud. If the torus is oriented alongside our line of sight, then the black gap is obscured. If we’re trying by way of the center area, then the black gap is unobscured. This mannequin is usually known as the doughnut mannequin, for the reason that torus is mainly formed like a doughnut.

If so, then there needs to be a random distribution of obscured and unobscured black holes. Since galaxies are oriented randomly, the “doughnuts” must also have random orientations. So the authors checked out information from the WISE infrared telescope, and recognized 170,000 supermassive black holes. They then seemed on the distribution of obscured and unobscured black holes. What they discovered was that obscured black holes have been extra prevalent in clusters of galaxies than unobscured ones. In different phrases they aren’t simply randomly distributed.

This implies the doughnut thought doesn’t match the info. Does this imply the entire unified mannequin thought of quasars, blazars, and radio galaxies must be discarded? No, however it does imply that the straightforward torus thought will have to be modified. Obscured black holes are extra clustered collectively, and we don’t know why.

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