The uncertainty of science: New research suggests first image in ’22 of Milky Way’s central black hole is likely not accurate

Sagittarius A*
The original interpretation. Click for full image.

The new interpretaion
The new asymmetrical interpretation. Click for original image.

Surprise, surprise! A new analysis of the data behind the 2022 false-color radio image of the supermassive black hole at the center of the Milky Way, posted to the right, suggests that image was not accurately interpreted from the data.

Astronomers led by the National Astronomical Observatory of Japan (NAOJ) say their analysis points at Sagittarius A* having an elongated accretion disk, as opposed to the ring-like “doughnut” image released in 2022 by an international team called the Event Horizon Telescope (EHT) collaboration.

The EHT image shows a central dark region where the hole resides, circled by the light coming from super-heated gas accelerated by immense gravitational forces.

But a new paper published today in Monthly Notices of the Royal Astronomical Society suggests that part of this appearance may actually be an artefact because of the way the image was put together. … Assistant professor Miyoshi Makoto, of the NAOJ, said: “Our image is slightly elongated in the east-west direction, and the eastern half is brighter than the western half. We think this appearance means the accretion disk surrounding the black hole is rotating at about 60 per cent of the speed of light.” He added: “Why, then, did the ring-like image emerge? Well, no telescope can capture an astronomical image perfectly. We hypothesise that the ring image resulted from errors during EHT’s imaging analysis and that part of it was an artefact, rather than the actual astronomical structure.”

It must be noted that this false color radio image was assembled from eight different radio telescopes across the globe, and to bring the data together required a great deal of massaging. While most astronomers appear to favor the top picture, it is just as likely that the bottom picture is a better representation. Either way, both must be considered in any future studies of Sagittarius A*’s environment and structure.

First radio image of event horizon of Milky Way’s central black hole

Sagittarius A*
Click for full image.

Using an array of eight radio telescopes worldwide, dubbed the Event Horizon Telescope because its purpose is to study black holes, scientists have obtained the first radio image of the event horizon of Sagittarius A* (pronounced “A-star”), the supermassive black hole at the center of the Milky Way.

The image to the right, reduced to post here, is that photo.

The image is a long-anticipated look at the massive object that sits at the very centre of our galaxy. Scientists had previously seen stars orbiting around something invisible, compact, and very massive at the centre of the Milky Way. This strongly suggested that this object — known as Sagittarius A* (Sgr A*, pronounced “sadge-ay-star”) — is a black hole, and today’s image provides the first direct visual evidence of it.

Although we cannot see the black hole itself, because it is completely dark, glowing gas around it reveals a telltale signature: a dark central region (called a “shadow”) surrounded by a bright ring-like structure. The new view captures light bent by the powerful gravity of the black hole, which is four million times more massive than our Sun.

This is the second supermassive black hole that the Event Horizon array has imaged. In 2019 it captured the central black hole of the galaxy M87, 55 million light years away. Like that first image, much of what we see here is created by computer, since the data from the eight radio telescopes needs to be massaged to create something as smooth and as complete as this.