Can anyone tell me books/papers related to any such effect.
I'm going to disagree with your basic premise(s) as you have stated it: There is nothing "virtual" about a photon emitted from a black hole...it's just like any other photon... it's "Hawking radiation" (or "black hole evaporation") and you can read about it via those names...which is all we can observe...but Hawking radiation has never been obvserved. It is based on quantum reasoning.
Photons are massless, but having energy (and momentum) do respond to a gravitational field...photons follow geodesics so they get curved in the presence of gravitational potential. A black hole has HUGE gravity, the most that a given volume can hold, so its EM fields outside the event horizon are also HUGE.
If a virtual photon pair appears just outside the event horizon of a black hole, and one is gobbled up by the black hole, the remaining photon is REAL. I don't think an isolated virtual photon has ever been detected, nor do we expect to ever do so. A photon always travels at the speed of light (locally) but as it moves away from a black hole it's frequency (and energy) is reduced...but it still moves at c locally. You could argue that the curvature due to the black hole causes it to take a different classical path, so maybe it takes longer to get to a given point, but all electromagnetic radiation has infinite reach.
A popular text, minimal math, that discusses black holes, horizons, information, virtual particles and such is THE BLACK HOLE WAR by Leonard Susskind..a founder of the holographic principle...the war was with Stephen Hawking.
If none of the above is what you were seeking, you might check out the four relativistic black hole solutions: Schwarzschild solution, Reissner–Nordström metric , Kerr metric, Kerr–Newman metric...
These have been discussed here on Physics Forums and you can find an introduction here:
http://en.wikipedia.org/wiki/Schwarzschild_metric
Be sure to read SEE ALSO at the bottom of the above reference...
Maybe somebody knows how these solutions affect electromagnetic radiation mathematically...mathematically/specifically...we generally consider electromagnetic and gravitation fields as varying the inverse of distance squared...don't know exactly how these might be affected by the above solutions...anybody??
