![]() The first image of SgrA* demonstrates the critical role astronomical research in Hawaiʻi plays on a world-wide scale. The Milky Way’s newly imaged black hole is more than 1,000 times smaller and less massive than Pōwehi making it much more challenging to image. In April 2017, the EHT project captured an image of Pōwehi, the world’s very first picture of a supermassive black hole at the center of the distant Messier 87 galaxy. The collective “Earth-sized” virtual telescope observed Sgr A* on multiple nights, and collected data for many hours in a row, similar to using a long exposure time on a camera to record the gas moving quickly around the black hole. ![]() JCMT and SMA, two of the world’s most powerful high frequency radio telescopes, provided coverage of the most western point. ![]() To produce the image, the team linked together eight existing radio observatories from across the globe to form a single “Earth-sized” virtual telescope. The EHT team’s study, published in a special issue of The Astrophysical Journal Letters, shows the black hole is about 27,000 light-years away from Earth, and its size on the sky is about the same as a donut would appear on the Moon. “We were stunned by how well the size of the ring agreed with predictions from Einstein’s Theory of General Relativity,” Bower explained. The new view captures light bent by the powerful gravity of the black hole. Although the black hole is not visible, because it is completely dark, glowing gas around it reveals a telltale signature, a dark central region or shadow surrounded by a bright ring-like structure. Scientists had previously seen stars orbiting around something invisible, compact and very massive in the heart of the Milky Way which strongly suggested that the object-known as Sagittarius A* (Sgr A*, pronounced “Sadge-A-star”)-was a black hole, and the long anticipated image provides the first direct visual evidence of it. Marrone University of Arizona) Click for larger image Individual telescopes involved in the EHT in April 2017, when observations were conducted. “These unprecedented observations have greatly improved our understanding of what happens at the very centre of our galaxy, and offer new insights on how these giant black holes interact with their surroundings,” said Geoffrey Bower, an affiliate astronomer at the University of Hawaiʻi at Mānoa and EHT project scientist, who led Hawaiʻi operations for the Institute of Astronomy and Astrophysics, Academia Sinica, Taipei. 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 including the James Clerk Maxwell Telescope ( JCMT) and the Submillimeter Array ( SMA) on Maunakea. ![]() This result provides overwhelming evidence that the object, 4-million-times more massive than the Sun, 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. (Credit: EHT Collaboration)Īstronomers have unveiled the first image of a supermassive black hole at the center of the Milky Way galaxy. First image of the black hole at the centre of the Milky Way. ![]()
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