Scientists from Mizusawa, Iwate talk about their team’s contribution to the first picture of a black hole

The original article was published in the Iwate Nichinichi (April 16th edition). Read the original here.

On April 15th, Iwate Nichinichi sat down with Dr. Mareki Honma and two other researchers at the Mizusawa VLBI Observatory in Oshu City to talk about the first-ever picture of a black hole released by the Event Horizon Telescope (EHT). “We were able to contribute to this result because the local residents believe in the work we’re doing. We’re grateful. We were able to achieve something amazing during this, the anniversary of the discovery of the Z-term (a term dealing with latitude variation of the Earth, discovered in Mizusawa 120 years ago).”

The EHT is a project helmed by around 200 people. There are 14 members in Japan, with six at the VLBI Observatory. On the 15th, Iwate Nichinichi sat with Honma (head of the observatory), Tomoaki Oyama (specially-appointed researcher in charge of devices), and Fumie Tazaki (specially-appointed researcher in charge of image processing).

The existence of black holes had been predicted, but humanity had not been able to actually see one. The EHT project joined together many different radio telescopes to form one giant telescope using VLBI (Very Long Baseline Interferometry). With this Earth-sized telescope, they were able to observe the black hole.

During imaging done in April 2017, the Mizusawa Observatory used the sparse modeling method to process the data, a mathematical method for gaining information from small amounts of data (used in MRIs as well). They also simulated various theoretical models using the Aterui II supercomputer at the observatory.

Data was taken from two black holes: a giant black hole in the middle of the M87 galaxy (an elliptical galaxy 55 million light years away), and the black hole in the middle of our own Milky Way called the Sagittarius A*. Honma said, “After some debate, it was affirmed that M87 was best for our first shot.” Tazaki added they had more data from M87.

As the image developed from analysis and processing became clearer, Dr. Tazaki said, “I felt so relieved. And it was exciting to be part of the team that was in charge of that process.”

Dr. Honma spoke about the importance of the project. “It’s an international project, so there were different opinions (on how to move forward), but it was so wonderful to overcome borders and move in the same direction in order to take this photo.” He said another success of the project was young researchers and experienced researchers working together and influencing each other.

The researchers also had messages for the local residents of Oshu City. Oyama said, “We have researchers right here who were closely connected to the effort to bring about the black hole picture. Please come visit us at the VLBI.” Tazaki said, “Researchers right here in Oshu City contributed to this picture that has the world in awe. I hope for the children of today to try new things too, things that will surprise everyone around them.”

This year marks the 120th anniversary of the discovery of the Z-term by Hisashi Kimura, who was the director of the Latitude Observatory in Mizusawa a century ago. “It may be a coincidence, but it was wonderful that we were able to achieve something huge during this anniversary year,” said Honma. “This is the result of all the researchers who worked on this project. And it is also due to the support of the residents of the city and our families.”

The EHT project will continue going forward. In 2020, they aim to add more organizations and continue their observations.