Active Galaxies

A supermassive black hole awakes

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Science  24 Feb 2017:
Vol. 355, Issue 6327, pp. 809-810
DOI: 10.1126/science.355.6327.809-d

Every large galaxy hosts a supermassive black hole at its center, which grows by consuming passing gas or stars. Most are quiescent, but when the black hole is feeding, an accretion disk forms, causing the galaxy nucleus to shine brightly as a quasar. Gezari et al. have discovered a bright quasar in a galaxy that was previously in an unremarkable quiescent state. As the black hole began feeding, the nucleus brightened by at least a factor of 10 in about a year. Such a rapid switch-on is unexpected, challenging theories of how quickly accretion disks can change state.

Astrophys. J. 10.3847/1538-4357/835/2/144 (2017).

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