This achievement was considerably more difficult than for M87*, even though Sgr A* is much closer to us. "We have two completely different types of galaxies and two very different black hole masses, but close to the edge of these black holes they look amazingly similar,” says Sera Markoff, co-chair of the EHT Science Council and a professor of theoretical astrophysics at the University of Amsterdam, the Netherlands. "This tells us that General Relativity governs these objects up close, and any differences we see further away must be due to differences in the material that surrounds the black holes.” The two black holes look remarkably similar, even though our galaxy’s black hole is more than a thousand times smaller and less massive than M87*. The breakthrough follows the EHT collaboration’s 2019 release of the first image of a black hole, called M87*, at the center of the more distant Messier 87 galaxy. Now a member in the lab of UC Santa Barbara/Las Cumbres Observatory astronomy professor Andy Howell, Farah conducted much of the work for this project as an undergrad at University of Massachusetts, Boston. He is the lead author on the paper released today, Selective dynamical imaging of interferometric data, in the special issue of The Astrophysical Journal Letters. The EHT observed Sgr A* on multiple nights, collecting data for many hours in a row, similar to using a long exposure time on a camera.įarah devised a new technique for producing a dynamical movie representation of the black hole Sgr A*. To image it, the team created the powerful EHT, which linked together eight existing radio observatories across the planet to form a single “Earth-sized” virtual telescope. "These unprecedented observations have greatly improved our understanding of what happens at the very center of our galaxy, and offer new insights on how these giant black holes interact with their surroundings.” The EHT team's results are being published today in a special issue of The Astrophysical Journal Letters.īecause the black hole is about 27,000 light-years away from Earth, it appears to us to have about the same size in the sky as a donut on the Moon. “We were stunned by how well the size of the ring agreed with predictions from Einstein’s Theory of General Relativity,” said EHT Project Scientist Geoffrey Bower from the Institute of Astronomy and Astrophysics, Academia Sinica, Taipei. 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 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.Īlthough 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. Scientists had previously seen stars orbiting around something invisible, compact, and very massive at the center of the Milky Way. The image is a long-anticipated look at the massive object that sits at the very center of our galaxy. The image was produced by a global research team called the Event Horizon Telescope (EHT) Collaboration, using observations from a worldwide network of radio telescopes. This result provides overwhelming evidence that the object is indeed a black hole and yields valuable clues about the workings of such giants, which are thought to reside at the center of most galaxies. UC Santa Barbara and Las Cumbres Observatory graduate student Joseph Farah participated this morning in a press conference in Washington D.C., where astronomers unveiled the first image of the supermassive black hole at the center of our own Milky Way galaxy. The image of the Sgr A* black hole is an average of the different images the EHT Collaboration has extracted from its 2017 observations. The telescope is named after the “event horizon,” the boundary of the black hole beyond which no light can escape.Īlthough we cannot see the event horizon itself, because it cannot emit light, glowing gas orbiting around the black hole reveals a telltale signature: a dark central region (called a “shadow”) surrounded by a bright ring-like structure. It was captured by the Event Horizon Telescope (EHT), an array which linked together eight existing radio observatories across the planet to form a single “Earth-sized” virtual telescope. It’s the first direct visual evidence of the presence of this black hole. This is the first image of Sagittarius A* (or Sgr A* for short), the supermassive black hole at the centre of our galaxy.
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