Jet from giant galaxy M87: Computer modelling explains black hole
observations
Further confirmation of Einstein's theory of general relativity

Date:
November 4, 2021
Source:
Goethe University Frankfurt
Summary:
An enormous jet of particles emitted by the giant galaxy M87 can
be observed astronomically in various wavelengths. Scientists
have developed a theoretical model of the morphology of this jet
using complex supercomputer calculations. The images from these
calculations provide an unprecedented match with astronomical
observations and confirm Einstein's theory of general relativity.



FULL STORY ==========================================================================
The galaxy Messier 87 (M87) is located 55 million light years away
from Earth in the Virgo constellation. It is a giant galaxy with 12,000 globular clusters, making the Milky Way's 200 globular clusters appear
modest in comparison. A black hole of six and a half billion sun masses
is harboured at the centre of M87. It is the first black hole for which an image exists, created in 2019 by the international research collaboration
Event Horizon Telescope.


==========================================================================
This black hole (M87*) shoots a jet of plasma at near the speed of light,
a so- called relativistic jet, on a scale of 6,000 light years. The
tremendous energy needed to power this jet probably originates from
the gravitational pull of the black hole, but how a jet like this comes
about and what keeps it stable across the enormous distance is not yet
fully understood.

The black hole M87* attracts matter that rotates in a disc in ever smaller orbits until it is swallowed by the black hole. The jet is launched
from the centre of the accretion disc surrounding M87, and theoretical physicists at Goethe University, together with scientists from Europe,
USA and China, have now modelled this region in great detail.

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

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

Dr Alejandro Cruz-Osorio, lead author of the study, comments: "Our
theoretical model of the electromagnetic emission and of the jet
morphology of M87 matches surprisingly well with the observations
in the radio, optical and infrared spectra. This tells us that the
supermassive black hole M87* is probably highly rotating and that the
plasma is strongly magnetized in the jet, accelerating particles out
to scales of thousands of light years." Professor Luciano Rezzolla,
Institute for Theoretical Physics at Goethe University Frankfurt,
remarks: "The fact that the images we calculated are so close to the astronomical observations is another important confirmation that
Einstein's theory of general relativity is the most precise and
natural explanation for the existence of supermassive black holes
in the centre of galaxies. While there is still room for alternative explanations, the findings of our study have made this room much smaller." ========================================================================== Story Source: Materials provided by Goethe_University_Frankfurt. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Alejandro Cruz-Osorio, Christian M. Fromm, Yosuke Mizuno, Antonios
Nathanail, Ziri Younsi, Oliver Porth, Jordy Davelaar, Heino Falcke,
Michael Kramer, Luciano Rezzolla. State-of-the-art energetic and
morphological modelling of the launching site of the M87 jet. Nature
Astronomy, 2021; DOI: 10.1038/s41550-021-01506-w ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/11/211104140122.htm

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