The Event Horizon of M87

Understand

The 6 billion solar mass supermassive black hole at the center of the giant elliptical galaxy M87 powers a relativistic jet.

• Observations at millimeter wavelengths with the Event Horizon Telescope have localized the emission from the base of this jet to angular scales comparable to the putative black hole horizon.
• The jet might be powered directly by an accretion disk or by electromagnetic extraction of the rotational energy of the black hole.
• However, even the latter mechanism requires a confining thick accretion disk to maintain the required magnetic flux near the black hole.