Black hole's affected by surrounding matter

Many black holes are affected by matter that is found around them. These objects that affect black       holes include orbiting stars, gas, planetary objects, comets, asteroids,  and many other celestial object.

When Black holes are affected astronomers can view the effects through X-ray emissions from the luminous black holes.  Astronomers, through X-ray emissions, can see the black hole's strong gravitational affects, its gravity redshifts, its gravitational light bending, its delays, and its dragging of inertial frames in the Kerr metric. 

The accretion disks that surround black holes include lots of dust that affect the energy outputs of the black holes.  These disks can create soft X-ray emission or hard X-ray emission.  These accretion disks can surround both spinning and non spinning black holes.  However, spinning black holes produce 5 times as much power as non spinning black holes.