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Will the Event Horizon Telescope picture of the shadow the Sagittarius A* agree with the prediction of general relativity ?


The Event Horizon Telescope (EHT) team is currently analyzing data that will allow for the imaging of the Sagittarius A*, the (presumed) supermassive black hole at the centre of our galaxy. See this article from Forbes for an account of the basics.

The team hopes to test various aspects of the region and compare to the properties general relativity predicts for a black hole of about 3.6 million solar masses. We can ask:

Will the inferred size of the Sagittarius A* object match predictions?

resolution is negative if the EHT generates a measurement of the physical size of the Sag A* object that leads to a 3-sigma equivalent or more conflict with the size of a black hole with the best known measurements of the object's mass (incorporating uncertainties in both). Resolution is positive if EHT measures the size and it is consistent (within 3-sigma) with those other measurement and that model, and ambiguous if no good measurement (say one within a factor of two) ends up being made, or if not publication is made prior to start of 2019.

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