The breakthrough follows the EHT collaboration’s 2019 release of the first image of a black hole, called M87*, at the centre of the more distant Messier 87 galaxy. 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. 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 centre 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 centre of the Milky Way.
The image is a long-anticipated look at the massive object that sits at the very centre 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 centre of most galaxies. The EHT is also laying the groundwork for extended observing campaigns to make movies of jet launching in M87.Astronomers have unveiled the first image of the supermassive black hole at the centre of our own Milky Way galaxy. The EHT is pushing toward observing at 345 GHz (0.87 mm), which will enable imaging at even higher angular resolution. In addition to these two sources, the EHT observes a wide range of AGN sources with prominent jets, ranging from radio galaxies to blazars, at a resolution unobtainable with any other instrument. Sgr A* has no obvious jet and is orders of magnitude smaller than M87 in mass and accretion rate. M87 is a low-luminosity active galactic nucleus (AGN) source that launches a jet that is prominent at radio and optical wavelengths. The two main targets for general relativity, M87 and Sgr A*, are very different in astrophysical character. The EHT also aims to understand the astrophysics of supermassive black hole systems. M87 and Sgr A* are the primary targets in which the photon ring is easily resolvable by the EHT. Confirming that the inner edge of the ring is circular and of the predicted size constitutes a test of general relativity in a strong-field environment. General relativity predicts that a bright photon ring will appear whose size is proportional to the mass of the black hole. The EHT aims to image the region affected by strong gravitational lensing around supermassive black holes. The Sparse Modeling Imaging Library for Interferometry (SMILI) has proven to be better than traditional imaging methods at reconstructing super-resolved images. Haystack is at the forefront in algorithms to turn calibrated data into images. Haystack is in the middle of a development program to modernize HOPS based on lessons learned from years of handling EHT data. Originally designed in the 1990s to handle geodetic VLBI data, HOPS has proven to be well suited to the challenges of reducing millimeter VLBI data. The main EHT data reduction pathway uses the Haystack Observatory Post-processing System (HOPS). Event Horizon Telescope observations were made by observations around the globe data was sent to MIT Haystack Observatory and the Max-Planck-Institut für Radioastronomie for correlation Algorithms
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