First Ever Image Captured of the Milky Way's Central Black Hole [Reading Science]

-Korea Astronomy and Space Science Institute + International 'EHT' Researchers Observe Supermassive Black Hole at the Center of the Milky Way
-Eight Radio Telescopes Worldwide Connected... Korea Participates with KVN and Others

[Asia Economy Reporter Kim Bong-su] An international joint research team, including a Korean research group, has succeeded for the first time in capturing an image of the black hole located at the center of our galaxy.

The Korea Astronomy and Space Science Institute (KASI) announced on the 12th that, together with the international joint research team participating in the Event Horizon Telescope (EHT), they captured an image of the supermassive black hole Sagittarius A (Sgr A) located at the center of our galaxy.

The EHT, or Event Horizon Telescope, is an international collaborative project that connects eight radio telescopes scattered around the world to create a virtual Earth-sized telescope to capture images of black holes. The Sagittarius A black hole discovered this time is the second black hole photographed by the EHT team following M87. Sagittarius A, located at the center of our galaxy, is about 27,000 light-years away from Earth and has a mass approximately 4 million times that of the Sun. It is a prime target for black hole research because it is about 1/2000th the distance from the solar system compared to the M87 black hole. However, it is more than 1,500 times less massive than M87. The gas flow around the black hole changes rapidly, and the image suffers from severe scattering effects, making observation more difficult than for M87.

The research involved over 300 EHT researchers from 80 institutions worldwide. In particular, to process the large-scale black hole observation data, supercomputers were used to analyze the data while simultaneously reproducing a large amount of black hole images for comparison through simulation experiments conducted continuously over five years. After correcting the observation data and completing the imaging process, the researchers discovered a ring-shaped structure and a dark region at the center, which is the shadow of the black hole.

The research team plans to develop theories analyzing the accretion flow around supermassive black holes. Through this, they expect to clarify the formation and evolution processes of galaxies, and anticipate that additional research will yield new results such as precise verification of general relativity.

KASI deployed three units of the Korean VLBI Network (KVN) for this research. Participating in the EHT multi-wavelength campaign, they confirmed that the structure of Sagittarius A black hole is close to circular. This suggests that the accretion disk plane of the black hole is oriented toward Earth. Additionally, KASI researchers, together with Korean researchers residing abroad, participated in the operation of major EHT telescopes such as the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile and the James Clerk Maxwell Telescope (JCMT) in Hawaii, carrying out various processes from observation, data processing, to imaging for this research.

Dr. Son Bong-won of KASI explained, “Sagittarius A black hole is the closest black hole directly observed by humanity through collective intelligence,” and added, “KASI is preparing for KVN to directly participate in the EHT beyond joint operation of ALMA and JCMT telescopes.”

The results of this research were published in The Astrophysical Journal on the same day.