The first image of the black hole in our galaxy , Sagittarius A*, is already a reality. It is the first direct visual evidence of the presence of this black hole. The Event Horizon Telescope (EHT) team presented the first photograph of a black hole in 2019, and today, May 12, 2022, we can see the first photo of Sagittarius A*.
The international presentation has had eight simultaneous press conferences around the world and is overwhelming proof that it is indeed a black hole and provides crucial clues about the functioning of these colossal objects of the cosmos that are believed to reside in the center of most galaxies in the universe .
The researchers have worked with a virtual telescope the size of the Earth, a tool that has only been possible with the combination of the capabilities of eight large telescopes located in different parts of the planet. To get the image, the team stitched together eight existing radio observatories around the planet to form a single virtual telescope observing our black hole over multiple nights, collecting data for many hours at a time, similar to using a long exposure time on a photografic camera. In total, more than 300 people from eight research institutes around the world have participated in this finding.
EHT scientists have been working for years to obtain images of the large black hole that occupies the interior of the Milky Way, Sagittarius A*, which has a mass equivalent to four million suns and is located about 27,000 light years away from Earth. .
What is Sagittarius A* like?
Sagittarius A* is virtually inactive and occasionally absorbs gas or dust, but apart from a few details, there were still many mysteries surrounding our galaxy’s supermassive black hole.
We can’t see the black hole itself as they trap everything that falls in, including light, so they are, in a very real sense, invisible, but the glowing gas that surrounds it does reveal a telltale signature: they warp the space-time around them so sharply that, when illuminated by bright streams of crushed falling matter in their gravitational grip, they cast a “shadow”, this shadow being surrounded by a bright ring-like structure. Sagittarius A* is hidden by a multi-layered veil.
“We were surprised by how well the ring size matched the predictions of Einstein’s general theory of relativity, ” said Geoffrey Bower, EHT project scientist, Institute for Astronomy and Astrophysics, Academia Sinica, Taipei. “These unprecedented observations have greatly improved our understanding of what is happening at the center of our galaxy and offer new insights into how these giant black holes interact with their surroundings.”
EHT scientists have discovered that the black hole at the center of the Milky Way is very similar to the black hole photographed in 2019, the one in the galaxy M87, even though the latter is monstrously larger than our own.
“These new EHT results are exciting because they show us how far astronomy has come and also because they confirm that there is still much out there that we haven’t seen and haven’t yet been able to observe and study,” said Tony Beasley, Director of the NRAO. “The antennas and instrumentation we design and develop at NRAO are making this progress possible, and we look forward to continuing to lead advances in radio astronomy that will uncover black holes and other phenomena lurking in the corners of the galaxy and universe.”
In addition to other facilities, the EHT network of radio observatories that made this image possible includes the Atacama Large Millimeter/submillimeter Array (ALMA) and the Atacama Pathfinder EXperiment (APEX), located in the Atacama Desert in Chile.
The mystery at the heart of the Milky Way has finally been solved.
Referencia: The Astrophysical Journal Letters: iopscience.iop.org/journal/2041-8205
