Last year we captured shadow of black hole at the centre of M87 by Event Horizon telescope. I am wondering if Hawking radiation can have any effect on the black hole shadow. The more I think about Hawking radiation: if it can have some observational effect on blackhole shadow, the more I am convinced that it won't because:

  • The basic principle of calculation of shadow is to find those photons which are just captured by the black hole. Hawking's calculation, on the other hand, doesn't even discuss the origin of that radiation, we just calculate a matrix element and bam! late time observer has the radiation. So how I'm going to incorporate that radiation in my calculation?
  • Blackhole shadow doesn't probe the event horizon(as far I understand by doing the calculation maybe this is wrong) for example for Schawarzschild black hole it's a circle of radius $3GM$.
  • For massive black hole it is just too small (their temp is very small).

Can someone tell me if there has been any work done on this idea because as far as I have seen papers on black hole shadow don't take hawking radiation into consideration?

  • $\begingroup$ Have you calculated the Hawking temperature for this black hole? $\endgroup$ – G. Smith Jun 29 at 6:23
  • $\begingroup$ @G.Smith yes for the Schwarzschild one by bogoliubov transformation. $\endgroup$ – aitfel Jun 29 at 6:30
  • $\begingroup$ I meant the value in Kelvins for the hole at the center of M87. $\endgroup$ – G. Smith Jun 29 at 6:32
  • $\begingroup$ @G.Smith It's of the order of -19 K while the temperature around may be different from the CMBR because of the accretion disc $\endgroup$ – aitfel Jun 29 at 6:41

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