Spin of the M87 Black Hole. Issue 4 (24th February 2020)

• Record Type: Journal Article
• Authors: Garofalo, David
• Is Part Of: Annalen der Physik. Volume 532:Issue 4(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-02-24
• Subjects: M87 -- supermassive black hole; Physics -- Periodicals; Chemistry -- Periodicals; 530.05
• DOI: 10.1002/andp.201900480
• Languages: English
• ISSNs: 0003-3804

Abstract

Abstract: Spin measurement of the 6.5 billion solar mass black hole in M87 from the Event Horizon Telescope image is the latest in a series that span a wide range in values, but that tend to share the feature of corotation between the accretion flow and black hole. The spin paradigm for black holes predicts very high black hole spin which in that framework is produced in its last significant merger. High black hole spin appears to be ruled out in the gap paradigm, however, which predicts early formation with a mass already in excess of 4 billion solar masses. In this picture, the black hole experiences slow evolution as it departs from its original radio quasar phase and over billions of years not only fails to double its mass but also falls short of regaining its original high spin, such that it is now compatible with a corotating accreting black hole whose dimensionless spin fits best in the range 0.2 < a < 0.5. Abstract : The black hole in M87 produces a powerful jet most likely produced by extraction of the rotational energy of the black hole from magnetic fields threading the horizon. While general relativistic magnetohydrodynamic simulations suggest the spin is close to its maximum value, the gap paradigm is compatible with the lower range 0.2 < a < 0.5.