Greenland telescope project: Direct confirmation of black hole with sub-millimeter VLBI

• Published in: Radio science 2014-07, Vol.49 (7), p.564-571
• Main Authors: Inoue, M., Algaba-Marcos, J. C., Asada, K., Blundell, R., Brisken, W., Burgos, R., Chang, C.-C., Chen, M.-T., Doeleman, S. S., Fish, V., Grimes, P., Han, J., Hirashita, H., Ho, P. T. P., Hsieh, S.-N., Huang, T., Jiang, H., Keto, E., Koch, P. M., Kubo, D. Y., Kuo, C.-Y., Liu, B., Martin-Cocher, P., Matsushita, S., Meyer-Zhao, Z., Nakamura, M., Napier, P., Nishioka, H., Nystrom, G., Paine, S., Patel, N., Pradel, N., Pu, H.-Y., Raffin, P. A., Shen, H.-Y., Snow, W., Srinivasan, R., Wei, T.-S.
• Format: Article
• Language: English
• Subjects: Black holes; submm and THz observing site; submm telescope; submm VLBI; supermassive Black Hole
• ISSN: 0048-6604; 1944-799X
• DOI: 10.1002/2014RS005450

A 12 m diameter radio telescope will be deployed to the Summit Station in Greenland to provide direct confirmation of a Super Massive Black Hole (SMBH) by observing its shadow image in the active galaxy M87. The telescope (Greenland Telescope: GLT) is to become one of the Very Long Baseline Interferometry (VLBI) stations at sub‐millimeter (submm) regime, providing the longest baseline >9000 km to achieve an exceptional angular resolution of 20 µas at 350 GHz, which will enable us to resolve the shadow size of ~40 µas. The triangle with the longest baselines formed by the GLT, the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, and the Submillimeter Array (SMA) in Hawaii will play a key role for the M87 observations. We have been working on the image simulations based on realistic conditions for a better understanding of the possible observed images. In parallel, retrofitting of the telescope and the site developments are in progress. Based on 3 years of opacity monitoring at 225 GHz, our measurements indicate that the site is excellent for submm observations, comparable to the ALMA site. The GLT is also expected to make single‐dish observations up to 1.5 THz. Key Points A submm telescope is coordinated to establish it at the Summit of Greenland Black Hole shadow imaging is the primary target for the submm VLBI The Summit shows low opacity at 225 GHz and is expected excellent up to THz regime