The famous image of a black hole needs to be corrected? Japanese scientists with allegations
When two years ago we saw an image of the black hole Sagittarius A* located in the heart of the Milky Way, it was a real sensation. Unfortunately, according to scientists from the National Astronomical Observatory of Japan, the effect may be inaccurate.
The image of the Sagittarius A black hole is the result of the work of the Event Horizon Telescope team, which is a network of eight ground-based such objects. The original analysis showed a bright ring structure surrounding a dark central region. This last part is a black hole that absorbs light (hence it cannot be shown in such an image). In turn, the color visible around it is the so-called accretion disc. And it is precisely this element that Japanese scholars have doubts about.
Different disc shape?
In their opinion, this disk may be more elongated than shown in the image resulting from the work of the Event Horizon Telescope. Problems with the interpretation and presentation of the collected data may result from the extremely complex analysis of radio interferometry data used to create the image.
We hypothesize that the ring image resulted from errors in the analysis of EHT imaging and that part of it was an artifact rather than an actual astronomical structure
– suggested Miyoshi Mikato from NAOJ, quoted by sciencealert.com.
According to NAOJ researchers, the disk surrounding Sgr A* is slightly elongated on the horizontal axis, and the right half is brighter than the left. This shape is supposed to influence the speed of rotation of this element and is supposed to be about 60% of the speed of light. The disk itself is filled with superheated material falling into a black hole with the mass of 4 million suns. Through the circulation of matter on the disk, the material is heated, which causes the emission of X-rays, visible light and even radio waves – describes sciencealert.com.
However, you may find that both depictions are accurate or both are wrong. All because of the complicated matter they are dealing with. The shape of the accretion disk itself is influenced by more factors than just the rotation of the black hole. It is also the rate of accretion itself, i.e. the amount of material that becomes part of the disk at a given time, and the momentum of the material carried that are important here.
At the same time, the gravitational pull of Sgr A* may also distort our view of the disk. The icing on the cake is the collected data, which, despite great accuracy, may still have gaps in information that researchers sometimes try to fill in themselves. That’s exactly what the EHT team did. The Japanese researchers in their paper indicate that the ring structure in the 2022 image published by EHT may be an artifact caused by the bumpy scatter function of the EHT data point. The NAOJ team reanalyzed the data and used a different mapping method to smooth out gaps in the data. This resulted in the conclusion about the elongated shape of the Sgr A* accretion disk.
