NGC 1365 seems to have a supermassive black hole in it, and ionized iron in its vicinity. The spectrum from the radiating iron has some odd features: are they due to the "frame dragging" around the spinning black hole or some interference from the clouds? Two X-ray space observatories, NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) and the European Space Agency’s XMM-Newton teamed up to determine that the clouds don't seem to be playing a major role.
If that is true, and the odd features in the iron spectrum are due to general relativistic effects around the black hole, then the thing must be spinning so fast that at its radius it must be moving at nearly the speed of light. I guess you have to collide two black holes or something equally dramatic to get the final one spinning that fast.
One way you can think of the weirdness is that orbiting the thing in one direction is slower than orbiting in the other; time doesn't work exactly the same way in both directions. Yes, it gives me a headache too.
3 comments:
More like a case of inner-ear queasiness for me!
Time doesn't work the same way, depending on the direction of orbit. Meaning that is (possibly) observably faster in one direction? Much faster, or just a bit? And direction in relation to what?
If the orbit is around the singularity in the same direction as the thing rotates, it is, IIRC, faster than if it goes the other way. How much depends on how massive the black hole is and how fast it is rotating--here the effect would be pretty dramatic. There's quite a jog in the iron line spectrum.
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