The first-ever image of our galaxy's Black Hole, Sagittarius A*, unveiled!

First image of Sagittarius A*, the supermassive black hole at the center of our galaxy. | EHT Collaboration

Astronomers announced on 13th May 2022 that they had captured the first picture of “the gentle giant” dwelling in our Milky Way galaxy: a supermassive black hole, famously known as Sagittarius A, a trapdoor in space-time through which the equivalent of four million suns have been dispatched to eternity, leaving behind only their gravity and violently bent space-time.

The new picture was captured by researchers from the Event Horizon Telescope (EHT) Collaboration who unveiled their first image in 2019. The group targeted both black holes at the outset but focused their attention on one at a time, owing to a difference in the complexity of the two projects.

The Event Horizon Telescope (EHT) is a large telescope array consisting of a global network of radio telescopes. The EHT project combines data from several very-long-baseline interferometry (VLBI) stations around Earth, which form a combined array with an angular resolution sufficient to observe objects the size of a supermassive black hole's event horizon.

Astronomers said the new result would lead to a better understanding of gravity, galaxy evolution and how even placid-seeming clouds of stars like our own majestic pinwheel of stars, the Milky Way, can generate quasars, enormous geysers of energy that can be seen across the universe. (NY Times)

The image of this object known as Sagittarius A-star, often referred to as Sgr A* (pronounced sadge-ay-star), shows the telltale sign of a black hole, as did the earlier one in the Messier 87 galaxy (M87): a bright ring of superhot glowing material circling a dark centre so dense and bottomless that not even light can escape. The way the light bends around the dark center, known as the event horizon, shows the object’s powerful gravity, which is four million times that of our sun.

The new picture, described today in a special issue of The Astrophysical Journal Letters, provides the first direct visual evidence that the giant lurking 27,000 light-years away at the center of Earth’s galaxy is, in fact, a supermassive black hole.

https://video.wixstatic.com/video/4c4215_d6e3077c7bea401095c23bb96f2a3d51/1080p/mp4/file.mp4

Simulations comparing M87 with SgrA* show how much faster material moving at the speed of light orbits SgrA* because of its smaller size. Center for Astrophysics | Harvard & Smithsonian

Members of the EHT project unveiled the picture at the National Press Club in Washington, D.C., shortly after 9 a.m. EST, in sync with six other news conferences in cities worldwide.

At the press conference in D.C., Michael Johnson, an astrophysicist at the CfA and a leading member of the EHT said one of the key lessons from the project was that the black hole at the center of the Milky Way doesn’t appear to be pulling in as much material as others, making the environment more relatively stable. (Harvard Gazette)