Bad Astronomy | Supermassive black hole in the M87 galaxy is seen by 19 observatories

Fifty-five million light-years from Earth lay a monster.

This is a supermassive black hole, one with a mass equivalent of 6.5 billion Sun. It can hide among the stars of the enormous elliptical galaxy M87, but it does it badly. It’s in the middle of the galaxy, the first place we would look. As it feeds, it also explodes the radiation of the material falling into it, making it bright and clear.

And it roars too. Two long rays of material shout at it with a high percentage the speed of light; fed, focused and fired by magnetic fields wrapped in the material as it revolves around The Point of No Return.

We are lucky that it is not very smart about attention. Because we monitor it closely, we use a literal fleet of observatories on as well as above the earth.

You’ve probably seen the incredible image of material around M87’s central supermassive black hole. The first was released in 2019 and was a revolution that shows the shadow of the back hole, the region around it, where even photons cannot rotate stably. Not long after astronomers saw changes in the material over time. And then, a few weeks ago, a second version was published showing the effects of the ridiculously powerful magnetic field wrapped around the case.

All the data was taken in 2017 by radio telescopes spread across the earth, combining their power to get a sharp view of a virtual telescope as big as a planet, called the Event Horizon telescope.

At almost the same time, 19 observatories monitoring the light across the electromagnetic spectrum, from radio waves to gamma rays, also observed the black hole. This type of campaign, called summary observations, helps astronomers understand what’s going on not only with different energies, but also on different spatial scales around the black hole.

The mass of the black hole, for example, is only known with an uncertainty of about 10%. The mass is determined by swallowing all the material seen in the images. But physical models must be used to determine the mass, and this makes assumptions about some properties that are not known. Observations at different wavelengths can help pin those better.

The jet of material flowing from the black hole is also a mystery. The details of how exactly the bright magnetic field orbits in the material orbiting the black hole are not well understood nor how it accelerates the rays of the intense gravity of the black hole. And what happens inside the jet when the material floods at such high speeds? We see tufts in the jet, and in some places faster gas clouds fall into slower moving material in front of them, causing tremendous shock waves. What effect does it have?

And the spatial scale, yikes. The jet starts very close to the black hole, just a few decades billions of miles away, but extends further 200,000 ligjare – it’s longer than our own Milky Way! You have to use different telescopes to look at all these scales – with different magnifications, if you will – to even have a prayer to understand what is going on in this maelstrom.

The almost simultaneous observations of the black hole and ray were made using the Event Horizon Telescope, but also Hubble (visible light), Chandra (X-rays), Fermi (gamma rays), Swift (X- and gamma rays), NuSTAR ( X-rays), and more. For a brief moment, some of the most powerful astronomers were locked on M87.

All of these data have been made public to the astronomy public so that eager scientists can attack and use them to sharpen their theoretical models. But the team (more than 750 scientists from nearly 200 institutions and 32 countries) were able to draw preliminary conclusions based on what they saw.

First, the activity of the supermassive black hole during the observations was at a historic low. Material falls into the black hole at different rates. Sometimes it is a steady stream and its brightness is also steady, sometimes a large gas cloud or star falls in and it becomes considerably brighter, and sometimes less matter falls in and the black hole is temporarily starved so that it fades. The low activity was useful in some ways, as it allowed astronomers to get observations so close (it would also be useful if we get similar observations of this for our own local supermassive black hole, Sgr A *).

We are pretty sure that the environment around black holes can also produce incredibly high-energy cosmic rays, which are subatomic particles, such as protons and helium atomic nuclei that move at almost the speed of light. Cosmic rays can hit our atmosphere and subtly affect the chemistry of the air and rocks on the surface. It is also a key to understanding other subatomic particles, and the fact that they exist can tell us how black holes generate them. Some are probably made in those radiation waves, but some can get close to the black hole.

Cosmic rays can make gamma rays as they strike inside the material, and the new observations looked at the extremely high-energy end of the spectrum. They found very little gamma ray coming close to the black hole, which is surprising. Does this mean that the ray dominates by making cosmic rays? Or is this low gamma radiation due to the low activity from the black hole?

Hopefully the new data will be extremely useful for astronomers trying to figure out what all the moving parts are doing here. It’s incredibly complex and we’re just beginning to understand it.

One thing I know for sure is that it is not enough to saturate astronomers. In a way, it looks a lot like the objects they study: Surrounded by massive amounts of data, greedy consumers of it, always wanting more, and sometimes exploding information and conclusions with high energy and at high speeds.

So stay tuned. A new stream of information from these observations will no doubt be on our way.

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