Frequency shifts in matter falling into a black hole
Abstract
We consider luminous test particles which are falling radially into a Schwarzschild black hole from rest at infinity. For an observer traveling with the particles inside of the horizon, we calculate the frequency shift of light received from sources in various directions and at positions up to r equals 5m. The differential equations for the particles and the photons are set up in Kruskal coordinates. They are valid both inside and outside the horizon. We find exclusively red shifts in radial directions. For light from offradial directions we find blue shifts in the vicinity of the observer, but increasing red shifts for sources further out. This behavior of frequency shifts is similar to that seen by comoving observers outside of the horizon.
 Publication:

Physical Review D
 Pub Date:
 December 1974
 DOI:
 10.1103/PhysRevD.10.3931
 Bibcode:
 1974PhRvD..10.3931T
 Keywords:

 Black Holes (Astronomy);
 Frequency Shift;
 Particle Motion;
 Red Shift;
 Schwarzschild Metric;
 Astronomical Models;
 Differential Equations;
 Gravitational Effects;
 Particle Interactions;
 Particle Trajectories;
 Radial Velocity;
 Astrophysics