A recent independent analysis of the data used to create the first image of a black hole in 2019 has confirmed the presence of a bright ring-like structure around the dark region. These findings were published on November 11 in the scientific journal Nature.
The study largely aligns with the initial conclusions of the Event Horizon Telescope (EHT), but it leaves open questions regarding the distribution of luminosity and the methods used for image reconstruction.
The international EHT collaboration presented the first image of a black hole shadow in 2019. The recorded structure was a glowing ring around the central dark zone, consistent with Albert Einstein's predictions from general relativity.
To obtain this image, the project combined simultaneous observations from radio telescopes located on different continents. These instruments function as a single virtual telescope with a resolution comparable to an Earth-sized antenna.
Nevertheless, the reconstruction process faces limitations. Since radio telescopes do not cover the entire surface of the planet, gaps in observations arise that must be compensated for using mathematical methods and computational models. The choice of these methods can influence the final result.
It is this aspect that raised doubts about the original image. Starting in 2022, astrophysicist Junichiro Makino from Kobe University in Japan and his colleagues began challenging the EHT's conclusions. By applying one of the methods used by the collaboration, but with different assumptions, the team obtained an image where the radio emissions appeared concentrated in an irregular structure rather than clearly forming a ring.
In response to these discrepancies, Samuel Lai, an astrophysicist from the Australian Centre for Scientific and Industrial Research (CSIRO), and his co-authors developed their own methodologies to re-examine the data. Their results generally matched the data presented by the EHT in 2019.
According to Nithyanandana Thyagarajan, a CSIRO astrophysicist and co-author of the study, different models used to guide the neural network can lead to slightly different reconstructions. He explained: 'Depending on your prior model, you may follow slightly different paths.'
Despite these differences, the researcher noted that the new group also discovered a ring-like structure.
However, Makino continues to question the results obtained. One of the differences noted by the researcher relates to the placement of the brightest points around the central structure, which changes depending on the reconstruction method used. He stated: 'If both methods are mathematically sound, it is difficult to understand why this happens.'
Thus, the new analysis confirms the general existence of a ring-like structure but does not establish definitive confirmation of all image details. The distribution of luminosity remains one of the areas of disagreement among different reconstructions.
