Fifty-five million light-years from Earth is a monster.
It is a supermassive black hole, with a mass equivalent to 6.5 billion Alone. It may be hiding among the stars in the huge elliptical galaxy M87, but it does a bad job of it. It is in the center of the galaxy, the first place we would look. In addition, as it feeds, it expels radiation from the material that falls into it, making it bright and obvious.
And he also roars. Two long rays of material escape at a high percentage of the speed of light; fed, focused, and fired by magnetic fields wrapped around the material as it swirls around the point of no return.
We are lucky that he is not very daring for attention. Because we are watching it closely, using a literal fleet of observatories both on and above Earth.
You’ve probably seen the amazing image of material around the M87’s central supermassive black hole. The first was launched in 2019 and meant a revolution, showing the shadow of the back hole, the region around it, even the photons cannot orbit stably. Shortly afterwards astronomers saw changes in this material over time. And then, a few weeks ago, a second version was released that showed the effects of the ridiculously powerful magnetic field wrapped around this matter.
All of this data was captured by 2017 radio telescopes scattered around the Earth, which combined its power to achieve sharp vision of a virtual telescope the size of a planet, called the Event Horizon Telescope.
Almost at the same time, 19 observatories that monitor light across the electromagnetic spectrum, from radio waves to gamma rays, also observed the black hole. This type of campaign, called synoptic observations, helps astronomers understand what is happening not only at different energies, but also at different spatial scales around the black hole.
For example, the mass of the black hole is only known with an uncertainty of about 10%. The mass is determined by how all the material seen in these images is swallowed. But physical models must be used to determine mass, and these make assumptions about some features that are not well known. Observations at different wavelengths can help nail them better.
Also, this stream of material flowing away from the black hole is a mystery. The details of how exactly the fierce magnetic field in the material orbiting the black hole ends up are not well known, nor how it really accelerates the jets of the intense gravity of the black hole. And what happens inside the beam when the material is flooded at such high speeds? We see agglomerations in the beam, and in some places faster gas clouds sink into material that moves slower ahead, creating huge shock waves. What effect does this have?
And the space ladder, yikes. The jet starts very close to the black hole, just a few tens of billions of kilometers from it, but extends to 200,000 light years – is longer than our Milky Way! It is necessary to use different telescopes that contemplate all these scales – that have different magnifications, if you want – even to make a prayer to understand what happens in this maelstrom.
Almost simultaneous observations of the black hole and the beam were made using the Event Horizon telescope, but also Hubble (visible light), Chandra (X-rays), Fermi (gamma rays), Swift (X-rays and gamma rays), NuSTAR X-rays) and more. For a brief moment, some of the most powerful eyes astronomers have were closed at M87.
All this data has been made known to the astronomical public so that eager scientists can attack it and use it to perfect their theoretical models. But the team (more than 750 scientists from nearly 200 institutions and 32 countries) was able to make some preliminary conclusions based on what they have seen.
On the one hand, activity from the supermassive black hole was at an all-time low during observations. The material falls into the black hole at different rates. Sometimes it is a constant flow and its brightness is also constant, sometimes a large cloud of gas or a star falls which illuminates considerably, and sometimes less matter falls into it, and the black hole dies of hunger temporarily. so that it is reduced. The low activity was somehow useful, as it allowed astronomers to obtain such close observations (it will also be useful when we obtain observations similar to that of our own local supermassive black hole, Sgr A *).
We are fairly certain that the environment around black holes can also produce incredibly high-energy cosmic rays, which are subatomic particles like protons and nuclei of helium atoms that move almost at the speed of light. Cosmic rays can affect our atmosphere and subtly affect the chemistry of the air and rocks on the surface. They are also key to understanding other subatomic particles, and the fact that they exist can tell us how black holes generate them. Some probably occur in these shock waves, but others may come from near the black hole.
Cosmic rays can produce gamma rays as blows around the inner material, and new observations examined that end of the extremely high energy spectrum. They found very little gamma ray light coming from the black hole, which is a bit surprising. Does this mean that the ray dominates in the realization of cosmic rays? Or is this low gamma ray count due to the low activity seen from the black hole?
Hopefully, the new data will be of great help to astronomers trying to figure out what all the moving parts do here. It’s incredibly complex and we’re just starting to understand it.
One thing I know for sure is that this is not enough to satiate astronomers. In a way, they closely resemble the objects they study: surrounded by large amounts of data, voracious consumers of them, always wanting more, and sometimes information and conclusions explode with a lot of energy and speed.
So stay tuned. No doubt a new stream of information from these observations will direct us soon.