What feature suggests the presence of a supermassive black hole or dense stellar remnants in the core of massive ellipticals like M87?

Answer

Steeply rising stellar velocities toward the center.

Observations showing stellar velocities rising sharply toward the galactic center in massive ellipticals strongly indicate the gravitational influence of a supermassive black hole or a dense concentration of stellar remnants.

What feature suggests the presence of a supermassive black hole or dense stellar remnants in the core of massive ellipticals like M87?
galaxiesastronomyelliptical galaxiesgalaxy classificationgalaxy shape