While mankind has recently accomplished the achievement of capturing the ‘Sagittarius A black hole’ at the center of our galaxy, a ‘new weapon’ to capture various celestial bodies, including black holes, is being built in the future. Starting next summer, driving tests will begin, and practical use will be possible next year. Based on its excellent performance, it is expected to be active in large international research such as the observation of black holes in our galaxy.
According to the Korea Astronomy and Space Science Institute on the 25th, the fourth telescope of the Korea Space Radio Observation Network (KVN) is currently being built on the Seoul National University Pyeongchang campus.
KVN is a system to which VLBI is applied. It is a method of simultaneously observing the same celestial body with several telescopes that are far away from each other and comprehensively analyzing the data to achieve high performance (resolution). The greater the distance between the telescopes, the larger the signal is amplified, and the more the telescope is stretched, the more lines (baselines) connecting each pair increase the performance. Existing KVN telescopes are being operated at Yonsei University in Seoul, Ulsan University in Ulsan, and Tamna University in Jeju.
The foundation for the fourth telescope will be completed next month. The pedestal serves to support the telescope structure. Construction of the observation building is expected to be completed in September.
Currently, the telescopic structure elements are being made, and the cone supporting the structure, the yoke and the yoke base that the upper structure moves, and the wheel and girder have already been manufactured, leaving only the painting process.
The production of key elements such as the main and sub-mirror, which plays a role of receiving signals, and the dish-shaped backup structure (BUS) that holds the shape of the main mirror, is also planned to be made soon. The Astronomical Institute will also begin assembling the telescope structure around September when the construction of the observation building is completed. In April of next year, it will carry out the core work of putting the main mirror surface and BUS on the telescope structure.
From July next year, the actual telescope driving test will begin and test observation will be conducted to verify the performance by the end of the year. If nothing happens, the telescope can be operated starting with some functions in 2024.
The fourth KVN telescope features a variety of weapons. By adding 230 GHz to 22, 43, 86, and 129 gigahertz (GHz) that the existing KVN can observe, a total of 5 channels can be simultaneously received.
This is the first time simultaneous observation of 5 channels. Above all, it is considered a very important achievement to include the 230 GHz region for simultaneous observation.
It also serves as a catalyst to increase the overall performance of KVN. In the case of the existing three-stage telescope, there are three baselines, but when the telescope is increased to four, the baseline is doubled to six. Considering the performance factors of the new telescope, it is expected that the KVN will perform more than twice as much as the previous one.
A fourth telescope is expected to be used in a project currently underway with the KVN. It contributes to research that explores jets of powerful energy from black holes and matter emitted by old stars. It is expected that the contribution will increase in the international joint research of the ‘Event Horizon Telescope (EHT)’ that captured the black hole of our galaxy. In the meantime, EHT research directly observed black holes with a 230 GHz telescope, and a low-frequency telescope was used as an assistant. Our research team also played a role in verifying the observation data in this black hole capture study. If the KVN is newly strengthened, it can add power to direct observation.
“We were concerned about the aftermath of COVID-19, but the construction of the telescope is in progress without serious difficulties,” said Byun Do-young, senior researcher at the Radio Astronomy Headquarters at the Astronomical Observatory. will increase,” he said.
Pyeongchang KVN Telescope Construction Progress and Plan
By Kim Young-jun, staff reporter [email protected]