The nature of obscured active galactic nuclei

Most galaxies host a supermassive black hole (SMBH) at their nucleus, one whose mass exceeds a million solar-masses. When material actively accretes onto the SMBH, associated processes can produce an active galactic nucleus ...

Supermassive black hole

A supermassive black hole is a black hole with a mass of the order of between 105 and 1010 solar masses. Most, if not all, galaxies, including the Milky Way, are believed to contain supermassive black holes at their centers.

Supermassive black holes have properties which distinguish them from their relatively low-mass cousins:

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