The Spin Angular Momentum and Black Hole Mass Components of Sagittarius A* · arXivDesk
2608.17978Aug 18, 20266 pages, summary of oral report presented at the Galactic Center workshop 2026 (IAU Symposium 405, Traversing the Galactic Center in Space and Time)
The Spin Angular Momentum and Black Hole Mass Components of Sagittarius A*
The dimensionless spin angular momentum, dimensionless spin function, and blackhole mass components of Sagittarius A* (Sgr A*) were obtained by Daly et al. (2024) by applying the outflow method to six independent sets of simultaneously or contemporaneously obtained X-ray and radio data. Here, results obtained for Sgr A* with the outflow method are reviewed. Consistent results were obtained with each data set. Set I (the preferred data set) indicates that Sgr A* has a dimensionless spin angular momentum a∗=(0.90±0.06) and a dimensionless spin function F=(0.62±0.10)
Nearby in the stack
. The results are consistent with the value of
a∗=(0.93±0.15)
obtained with the outflow method applied to an independent data set (Daly 2019). The application of the outflow method to a weak compact radio source such as Sgr A* in its current state is most accurately determined with simultaneous or contemporaneous radio and X-ray measurements.