First Very Long Baseline Interferometry Detections at 870 μm
Alexander W. Raymond, Sheperd S. Doeleman, Keiichi Asada, Lindy Blackburn, Geoffrey C. Bower, Michael Bremer, Dominique Broguière, Ming‐Tang Chen, G. Crew, Sven Dornbusch, Vincent L. Fish, Roberto García, Olivier Gentaz, C. Goddi, Chih-Chiang Han, M. H. Hecht, Teddy Huang, Michaël Janssen, Garrett K. Keating, Jun Yi Koay, T. P. Krichbaum, Wen-Ping Lo, Satoki Matsushita, Lynn D. Matthews, J. M. Moran, Timothy Norton, Nimesh Patel, Dominic W. Pesce, Venkatessh Ramakrishnan, Helge Rottmann, A. L. Roy, Salvador Sánchez, R. P. J. Tilanus, Michael Titus, Pablo Torné, Jan Wagner, Jonathan Weintroub, Maciek Wielgus, André Young, Kazunori Akiyama, Ezequiel Albentosa-Ruíz, A. Alberdi, Walter Alef, Juan Carlos Algaba, Richard Anantua, Rebecca Azulay, U. Bach, Anne-Kathrin Baczko, David Ball, Mislav Baloković, Bidisha Bandyopadhyay, John Barrett, Michi Bauböck, B. A. Benson, Dan Bintley, R. Blundell, Katherine L. Bouman, Hope Boyce, Roger Brissenden, S. Britzen, Avery E. Broderick, Thomas Bronzwaer, Sandra Bustamante, J. E. Carlstrom, Andrew Chael, Chi‐kwan Chan, Dominic O. Chang, Koushik Chatterjee, Shami Chatterjee, Yongjun 永军 Chen 陈, Xiaopeng Cheng, Ilje Cho, Pierre Christian, Nicholas S. Conroy, J. E. Conway, T. M. Crawford, Alejandro Cruz-Osorio, Yuzhu Cui, Rohan Dahale, Jordy Davelaar, Mariafelicia De Laurentis, Roger Deane, Jessica Dempsey, G. Desvignes, Jason Dexter, Vedant Dhruv, Indu K. Dihingia, Sergio A. Dzib, Ralph P. Eatough, Razieh Emami, H. Falcke, Joseph Farah, E. B. Fomalont, Anne-Laure Fontana, H. Alyson Ford, Marianna Foschi, Raquel Fraga-Encinas, William T. Freeman, Per Friberg, Christian M. Fromm
Abstract
Abstract The first very long baseline interferometry (VLBI) detections at 870 μ m wavelength (345 GHz frequency) are reported, achieving the highest diffraction-limited angular resolution yet obtained from the surface of the Earth and the highest-frequency example of the VLBI technique to date. These include strong detections for multiple sources observed on intercontinental baselines between telescopes in Chile, Hawaii, and Spain, obtained during observations in 2018 October. The longest-baseline detections approach 11 G λ , corresponding to an angular resolution, or fringe spacing, of 19 μ as. The Allan deviation of the visibility phase at 870 μ m is comparable to that at 1.3 mm on the relevant integration timescales between 2 and 100 s. The detections confirm that the sensitivity and signal chain stability of stations in the Event Horizon Telescope (EHT) array are suitable for VLBI observations at 870 μ m. Operation at this short wavelength, combined with anticipated enhancements of the EHT, will lead to a unique high angular resolution instrument for black hole studies, capable of resolving the event horizons of supermassive black holes in both space and time.