M87 as Black Hole Candidate

The case for identifying an object as a black hole sometimes takes the form of eliminating other possible explanations for its behavior. Shown below is an image captured by the Wide Field and Planetary Camera of the Hubble Space Telescope. It is a portion of the active galaxy M87 showing a spiral of hot gas at its center. The inset at upper left shows the central region. Measurements by the space telescope indicate that the central disc is rotating so rapidly that a black hole is likely the energy source. Further evidence comes from the brilliant relativistic jet of electrons seen as a diagonal line at lower right. This also points to a black hole "engine" to supply that kind of energy in that small a volume of space. The volume from which the energy emanates is no larger than our solar system. Models of the phenomena indicate a black hole at the center of M87 with as much as 3 billion solar masses.