Astronomers Throw Shade At Image Of Supermassive Black Hole In Center Of Milky Way

hero eht collaboration image
Researchers from Japan’s National Astronomical Observatory (NAOJ) are throwing shade at the now iconic image of the supermassive black hole at the center of the Milky Way captured by the Event Horizon Telescope (EHT). The image in question, constructed by another group of researchers from data collected by the EHT, was revealed to the public for the first time in 2022.

The EHT Collaboration unveiled the image of the black hole at the heart of the Milky Way, known as Sagittarius A* (Sgr A*) during a live stream in May 2022, while discussing how they developed the first image of Sgr A*. This led scientists and astronomers to study Sgr A* in polarized light, which they believed provided strong evidence that powerful magnetic fields may be common to all black holes, as well as hinting at the supermassive black hole hiding a jet. However, new research may indicate the first image of Sgr A* may not be accurate, even though many other researchers say they validated the results.

The latest research points to Sgr A* as having an elongated accretion disk, instead of the ring-like “doughnut” image released in 2022 by the EHT Collaboration. The research suggests that part of the appearance could be an artifact due to the way the image was put together.

new sgr a image cropped
New final image of Sgr A* obtained from NAOJ imaging process.

“Our image is slightly elongated in the east-west direction, and the eastern half is brighter than the western half,” explained assistant professor Miyoshi Makoto of the NAOJ. He continued, “We think this appearance means the accretion disk surrounding the black hole is rotating at about 60 percent of the speed of light.”

Makoto added no telescope can capture an astronomical image perfectly. He also said the group of astronomers he is associated with hypothesized the ring image provided by the EHT collaboration resulted from errors during EHT’s imaging analysis, with an artifact causing the problem.

Another aspect of the opposing images lies in the fact data from observations differs greatly from typical photography. Special algorithms are utilized to construct images from the observed data. As different research teams employ different algorithms, differing images are bound to occur, as well as theories as to which is correct.

According to the Royal Astronomical Society, the NAOJ team applied widely used traditional methods to EHT data, as opposed to the EHT’s own original analysis method. While the appearance of Sgr A* provided by the new research differs from that of the EHT Collaboration’s, both are considered to be plausible structures derived from the data using the respective methods.

If the new research into the EHT's Sgr A* data proves anything, it is as Makoto pointed out, capturing images of structures such as Sgr A* is hard, and deciphering the data collected can be even harder.