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| Paper: |
Testing Theories of Gravity via Black Hole Shadows in Sgr A* |
| Volume: |
528, New Horizons in Galactic Center Astronomy and Beyond |
| Page: |
255 |
| Authors: |
Mizuno, Y.; Younsi, Z.; Fromm, C. M.; Porth, O.; De Laurentis, M.; Olivares, H.; Falcke, H.; Kramer, M.; Rezzolla, L. |
| Abstract: |
Upcoming sub-millimetre very-long-baseline-interferometry (VLBI) images of Sagittarius A* (Sgr A*) carried out by the Event Horizon Telescope (EHT) Collaboration are expected to provide critical evidence for the existence of a supermassive black hole at our galactic centre. In this work we assess our present ability to use EHT images to determine if they correspond to a Kerr black hole as predicted by Einstein's theory of general relativity or to a black hole in alternative theories of gravity. To this end, we perform general relativistic magnetohydrodynamic simulations and use general relativistic radiation transfer calculations to generate synthetic shadow images of a magnetized accretion flow onto a Kerr black hole and a non-rotating dilaton black hole, which we take as a representative solution of an alternative theory of gravity. Taking into account the VLBI configuration of the 2017 EHT observation of Sgr A*, we found that it could be difficult to distinguish between black holes from different theories of gravity, unless additional information were available. |
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