Astrophysicists reweighed the “photographed” black hole

UNITED STATES (OBSERVATORY NEWS) — In April 2019, scientists first received the image of a black hole. Then they determined its mass. Now astronomers from Russia, Italy and the USA have weighed this “model” using a different method and obtained unexpected results.

The achievement is described in a scientific article published in the journal Astronomy and Astrophysics.

The first black hole for which it was possible to obtain an image of the event horizon turned out to be a “predator” in the center of the M87 galaxy. The “snapshot” was obtained thanks to the grandiose system of radio telescopes EHT, scattered across several continents. According to the results of this study, experts determined its mass: approximately six billion suns.

This figure is much higher than previous estimates based on observations of the M87 galaxy using optical telescopes. Therefore, the authors of the new article decided to double-check the data of colleagues.

They used the relationship between the mass of a black hole and the characteristics of the x-ray radiation of a substance incident on it. As specified in a press release from Moscow State University named after M.V. Lomonosov, this method is widely known and tested on many black holes both in the Galaxy and beyond.

It turned out that the “mistress” of M87 weighs only 50 million suns. This is about a hundred times less than the EHT team did.

To check their own calculations, the authors used the same method to weigh the central black hole of the galaxy 3C 454.3. The mass of this object is well known and measured in several different ways.

The result of astronomers according to 3C 454.3 was in good agreement with all other measurements of the mass of this black hole. This means, the researchers conclude, that the method works well.

It turns out that the problem arose nevertheless when determining the mass according to EHT data. Recall that this was the first such observation in history, so that humanity has no experience in such measurements.

On the other hand, the clue may be hidden in the object M87. Perhaps, for some reason, the “x-ray” method works poorly for him. Further observations should put an end to this question.


This article is written and prepared by our foreign editors writing for OBSERVATORY NEWS from different countries around the world – material edited and published by OBSERVATORY staff in our newsroom.

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