Behavior of the Black Hole at the Center of our Galaxy
University of California, Santa Barbara | 2020 Jun 15
Like most galaxies, the Milky Way hosts a supermassive black hole at its center. Called Sagittarius A*, the object has captured astronomers’ curiosity for decades. And now there is an effort to image it directly.
The incredibly strong solar winds are visible in Ressler and White’s simulation of the
Wolf-Rayet stars orbiting Sagittarius A*. Credit: Sean Ressler, Chris White (UCSB)
Catching a good photo of the celestial beast will require a better understanding of what’s going on around it, which has proved challenging due to the vastly different scales involved. “That’s the biggest thing we had to overcome,” said Sean Ressler, ... who just published a paper ... investigating the magnetic properties of the accretion disk surrounding Sagittarius A*.
In the study, Ressler, ... Chris White and their colleagues ... sought to determine whether the black hole’s magnetic field, which is generated by in-falling matter, can build up to the point where it briefly chokes off this flow, a condition scientists call magnetically arrested. Answering this would require simulating the system all the way out to the closest orbiting stars.
The system in question spans seven orders of magnitude. The black hole’s event horizon, or envelope of no return, reaches around 4 to 8 million miles from its center. Meanwhile, the stars orbit around 20 trillion miles away, or about as far as the sun’s nearest neighboring star. ...
Ab Initio Horizon-scale Simulations of Magnetically Arrested Accretion
in Sagittarius A* Fed by Stellar Winds ~ Sean M. Ressler et al
- Astrophysical Journal Letters 896(1):L6 (2020 Jun 10) DOI: 10.3847/2041-8213/ab9532
- arXiv.org > astro-ph > arXiv:2006.00005 > 29 May 2020 (v1), 12 Jun 2020 (v2)