Supercomputers model the first black hole ever imaged


Along the magnetic field lines, the particles are accelerated so efficiently that they form a jet at scales of 6000 light years in the case of M87.
ALEJANDRO CRUZ-OSORIO

Theoretical physicists have succeeded in modeling, with the computing power of 3D supercomputers, the supermassive black hole at the center of the galaxy Messier 87, first of which an image exists.

Messier 87 (M87) is located 55 million light years from Earth in the constellation Virgo. It is a giant galaxy with 12,000 globular clusters, which makes the Milky Way’s 200 globular clusters appear modest in comparison. A 6.5 billion solar mass black hole is housed at the center of M87. In 2019, the international research collaboration EHT (Event Horizon Telescope) obtained the first image of an object of this nature.

This black hole shoots out a jet of plasma at a speed close to the speed of light, a so-called relativistic jet, on a 6,000 light-year scale. The tremendous energy required to drive this jet probably stems from the gravitational pull of the black hole, but how a jet like this is produced and what keeps it stable across the enormous distance is not yet fully understood.

M87 attracts matter that rotates in a disk in smaller and smaller orbits until it is swallowed by the black hole. The jet is launched from the center of the accretion disk surrounding M87, and theoretical physicists at Goethe University, along with scientists from Europe, the United States and China, have modeled this region in great detail.

They used highly sophisticated three-dimensional supercomputer simulations using a staggering one million CPU hours per simulation and had to simultaneously solve Albert Einstein’s equations of general relativity, the equations of James Maxwell’s electromagnetism and Leonhard Euler’s fluid dynamics equations.

The result was a model in which the calculated values ​​for temperatures, matter densities and magnetic fields correspond remarkably well with what was deduced from astronomical observations. On this base, the scientists were able to trace the complex motion of photons in the curved spacetime of the jet’s innermost region and translate it into radio images. They were then able to compare these computer-modeled images with observations made using numerous radio telescopes and satellites over the past three decades.

Dr. Alejandro Cruz-Osorio, lead author of the study, comments in a statement: “Our theoretical model of the electromagnetic emission and the morphology of the M87 jet matches surprisingly well with the observations in the radio, optical and infrared spectra. This tells us that the supermassive black hole M87 probably spins around a lot and the plasma is strongly magnetized in the jet., accelerating particles to scales of thousands of light years. ”

Professor Luciano Rezzolla, from the Institute for Theoretical Physics at the Goethe University in Frankfurt, notes: “The fact that the images we calculate are so close to the astronomical observations is another important confirmation that the Einstein’s theory of general relativity is the most accurate and natural explanation for the existence of supermassive black holes at the center of galaxies. While there is still room for alternative explanations, the findings of our study have made this possibility much smaller. ”The findings were published in Nature Astronomy.

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