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Capabilities and prospects of the East Asia Very Long Baseline Interferometry Network


The very long baseline interferometry (VLBI) technique offers angular resolutions superior to any other instruments at other wavelengths, enabling unique science applications of high-resolution imaging of radio sources and high-precision astrometry. The East Asia VLBI Network (EAVN) is a collaborative effort in the East Asian region. The EAVN currently consists of 21 telescopes with diverse equipment configurations and frequency setups, allowing flexible subarrays for specific science projects. The EAVN provides the highest resolution of 0.5 mas at 22 GHz, allowing the fine imaging of jets in active galactic nuclei, high-accuracy astrometry of masers and pulsars, and precise spacecraft positioning. The soon-to-be-operational Five-hundred-meter Aperture Spherical radio Telescope (FAST) will open a new era for the EAVN. This state-of-the-art VLBI array also provides easy access to and crucial training for the burgeoning Asian astronomical community. This Perspective summarizes the status, capabilities and prospects of the EAVN.

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Fig. 1: Geographic distribution of the EAVN telescopes and correlators.
Fig. 2: Comparison of uv coverages on a 12-hour track of the EAVN with the EVN and the VLBA at 22 GHz frequency band.
Fig. 3: A sketch map of the EAVN science cases and corresponding subarrays and frequency setups.
Fig. 4: The radio structure of the giant radio galaxy M87.
Fig. 5: Interstellar masers (harboured in star-forming regions) are used for determining the Galactic structure.
Fig. 6: Motion of the Chang'E-3 rover with respect to the lander determined by phase-referencing VLBI, which produces an image at each parking site from A to E.


  1. Kardashev, N. S. et al. “RadioAstron”—A telescope with a size of 300 000 km: main parameters and first observational results. Astron. Rep. 57, 153–194 (2013).

    ADS  Article  Google Scholar 

  2. Doeleman, S. et al. Imaging an event horizon: submm-VLBI of a super massive black hole. In Astro2010: The Astronomy and Astrophysics Decadal Survey, Science White Paper no. 68. Preprint at (2009).

  3. Kellermann, K. I. & Moran, J. M. The development of high-resolution imaging in radio astronomy. Ann. Rev. Astron. Astrophys. 39, 457–509 (2001).

    ADS  Article  Google Scholar 

  4. Clark, B. G. A review of the history of VLBI. In Radio Astronomy at the Fringe (eds Zensus, A. J., Cohen, M. H. & Ros, E.) 1–8 (ASP Conf. Ser. Vol. 300, Astronomical Society of the Pacific, San Francisco, 2003).

  5. Honma, M., Akiyama, K., Uemura, M. & Ikeda, S. Super-resolution imaging with radio interferometry using sparse modeling. Publ. Astron. Soc. Jpn 66, 95–108 (2014).

    ADS  Article  Google Scholar 

  6. Ikeda, S., Tazaki, F., Akiyama, K., Hada, K. & Honma, M. PRECL: a new method for interferometry imaging from closure phase. Publ. Astron. Soc. Jpn 68, 45–53 (2016).

    ADS  Article  Google Scholar 

  7. Ye, S., Wan, T. & Qian, Z. Progress on Chinese VLBI network project. In Radio Interferometry: Theory, Techniques, and Applications, IAU Colloq. 131 (eds Cornwell, T. J. & Perley, R. A.) 386–389 (ASP Conf. Ser. Vol. 19, Astronomical Society of the Pacific, San Francisco, 1991).

  8. Doi, A. et al. Japanese VLBI Network. In Proc. 8th European VLBI Network Symposium (eds Baan W. A. et al.) PoS (8thEVN) 71 (2006).

  9. Kobayashi, H. et al. VERA: a new VLBI instrument free from the atmosphere. In New Technologies in VLBI (ed. Minh, Y. C.) 367–371 (ASP Conf. Ser. Vol. 306, Astronomical Society of the Pacific, San Francisco, 2003).

  10. Minh, Y. C., Roh, D.-G., Han, S.-T. & Kim, H.-G. Construction of the Korean VLBI Network (KVN). In New Technologies in VLBI(ed. Minh, Y. C.) 373–382 (ASP Conf. Ser. Vol. 306, Astronomical Society of the Pacific, San Francisco, 2003).

  11. Nan, R. et al. The Five-hundred-meter Aperture Spherical radio Telescope (FAST) project. Int. J. Mod. Phys. D. 20, 989–1024 (2011).

    ADS  Article  Google Scholar 

  12. Nan, R. D. & Zhang, H. Y. Super bowl. Nat. Astron. 1, 0012 (2017).

    ADS  Article  Google Scholar 

  13. Kawaguchi, N., Sasao, T. & Manabe, S. Dual-beam VLBI techniques for precision astrometry of the VERA project. In Proc. SPIE. Vol. 4015 (ed. Butcher, H. R.) 544–551 (SPIE, Bellingham, 2000).

  14. Honma, M., Kawaguchi, N. & Sasao, T. Science with VERA: VLBI exploration of radio astrometry. In Proc. SPIE. Vol. 4015 (ed. Butcher, H. R.) 624–631 (SPIE, Bellingham, 2000).

  15. Kim, H.-G., Han, S. T. & Sohn, B. W. The Korean VLBI Network project. In Exploring the Cosmic Frontier: Astrophysical Instruments for the 21st Century Vol. 37, (eds Lobanov, A. P., Zensus, J. A., Cesarsky, C. & Diamond, P. J.) 41–42 (ESO Astrophysics Symposia, Berlin, 2007).

  16. Han, S.-T. et al. Millimeter-wave receiver optics for Korean VLBI Network. Int. J. Infrared Millim. Waves 29, 69–78 (2008).

    ADS  Article  Google Scholar 

  17. Rioja, M. J. et al. Verification of the astrometric performance of the Korean VLBI Network, using comparative SFPR studies with the VLBA at 14/7 mm. Astron. J. 148, 84–98 (2014).

    ADS  Article  Google Scholar 

  18. Hagiwara, Y. et al. Current status of the EAVN experiments. Publ. Korean Astron. Soc. 30, 641–643 (2015).

    ADS  Google Scholar 

  19. Lee, S.-S. et al. Early science with the Korean VLBI Network: evaluation of system performance. Astron. J. 147, 77–90 (2014).

    ADS  Article  Google Scholar 

  20. Wajima, K. et al. The East-Asian VLBI Network. In Frontiers in Radio Astronomy and FAST Early Sciences Symposium (eds Qian, L. & Li, D.) 81–86 (ASP Conf. Ser. Vol. 502, Astronomical Society of the Pacific, San Francisco, 2016).

  21. Niinuma, K. et al. VLBI observations of bright AGN jets with the KVN and VERA Array (KaVA): evaluation of imaging capability. Publ. Astron. Soc. Jpn. 66, 103–118 (2014).

    ADS  Article  Google Scholar 

  22. Matsumoto, N. et al. The first very long baseline interferometry image of a 44 GHz methanol maser with the KVN and VERA Array (KaVA). Astrophys. J. Lett. 789, L1–L6 (2014).

    ADS  Article  Google Scholar 

  23. Yun, Y. J. et al. SiO masers around WX Psc mapped with the KVN and VERA Array (KaVA). Astrophys. J. 822, 3–11 (2016).

    ADS  Article  Google Scholar 

  24. Whitney, A. R. et al. Quasars revisited: rapid time variations observed via very-long-baseline interferometry. Science 173, 225–230 (1971).

    ADS  Article  Google Scholar 

  25. Cohen, M. H. et al. The small-scale structure of radio galaxies and quasi-stellar sources at 3.8 centimeters. Astrophys. J. 170, 207–217 (1971).

    ADS  Article  Google Scholar 

  26. Hada, K. et al. An origin of the radio jet in M87 at the location of the central black hole. Nature 477, 185–187 (2011).

    ADS  Article  Google Scholar 

  27. Doi, A. et al. Japanese VLBI Network observations of radio-loud narrow-line Seyfert 1 galaxies. Publ. Astron. Soc. Jpn 59, 703–709 (2007).

    ADS  Article  Google Scholar 

  28. An, T. et al. VLBI observations of 10 compact symmetric object candidates: expansion velocities of hot spots. Astrophys. J. Suppl. Ser. 198, 5–24 (2012).

    ADS  Article  Google Scholar 

  29. Zhang, Y. K. et al. J0906+6930: a radio-loud quasar in the early Universe. Mon. Not. R. Astron. Soc. 468, 69–76 (2017).

    ADS  Article  Google Scholar 

  30. Reid, M. J. & Moran, J. M. Masers. Ann. Rev. Astron. Astrophys. 19, 231–276 (1981).

    ADS  Article  Google Scholar 

  31. Reid, M. J. & Honma, M. Microarcsecond radio astrometry. Ann. Rev. Astron. Astrophys. 52, 339–372 (2014).

    ADS  Article  Google Scholar 

  32. Honma, M. et al. Fundamental parameters of the Milky Way galaxy based on VLBI astrometry. Publ. Astron. Soc. Jpn 64, 136–148 (2012).

    ADS  Article  Google Scholar 

  33. Imai, H. et al. Japanese VLBI Network mapping of SiO υ = 3 J = 1–0 maser emission in W Hydrae. Publ. Astron. Soc. Jpn 62, 431–439 (2010).

    ADS  Article  Google Scholar 

  34. Matsumoto, N. et al. Astrometry of 6.7 GHz methanol maser toward W3(OH) with Japanese VLBI Network. Publ. Astron. Soc. Jpn 63, 1345–1356 (2011).

    ADS  Article  Google Scholar 

  35. Fujisawa, K. et al. Observations of 6.7 GHz methanol masers with East-Asian VLBI Network. I. VLBI images of the first epoch of observations. Publ. Astron. Soc. Jpn 66, 31–59 (2014).

    ADS  Article  Google Scholar 

  36. Imai. H. Stellar molecular jets traced by maser emission. In IAU Symposium, Vol. 242 (eds Chapman, J. M. & Baan, W. A.) 279–286 (Cambridge Univ. Press, Cambridge, 2007).

  37. Baan, W. A., Wood, P. A. D. & Haschick, A. D. Broad hydroxyl emission in IC4553. Astrophys. J. Lett. 260, L49–L52 (1982).

    ADS  Article  Google Scholar 

  38. Lo, K. Y. Mega-masers and galaxies. Ann. Rev. Astron. Astrophys. 43, 625–676 (2005).

    ADS  Article  Google Scholar 

  39. Tong, F., Zheng, W. & Shu, F. Accurate relative positioning of Yutu lunar rover using VLBI phase-referencing mapping technology. Chin. Sci. Bull. 59, 3362–3369 (2014).

    Article  Google Scholar 

  40. Liu, Q. et al. Monitoring motion and measuring relative position of the Chang’E-3 rover. Radio Sci. 49, 1080–1086 (2014).

    ADS  Article  Google Scholar 

  41. Weiler, K. W., Panagia, N., Monters, M. J. & Sramek, R. A. Radio emission from supernovae and gamma-ray bursters. Ann. Rev. Astron. Astrophys. 40, 387–438 (2002).

    ADS  Article  Google Scholar 

  42. Brisken, W. F., Benson, J. M., Goss, W. M. & Thorsett, S. E. Very Long baseline array measurement of nine pulsar parallaxes. Astrophys. J. 571, 906–917 (2002).

    ADS  Article  Google Scholar 

  43. Deller, A. T., Verbiest, J. P. W., Tingay, S. J. & Bailes, M. Extremely high precision VLBI astrometry of PSR 0437–4715 and implications for theories of gravity. Astrophys. J. Lett. 685, L67–L70 (2008).

    ADS  Article  Google Scholar 

  44. Dodson, R. et al. The KaVA and KVN Pulsar Project. Publ. Astron. Soc. Jpn 66, 105–117 (2014).

    ADS  Article  Google Scholar 

  45. Counselman, C. C. III Radio astrometry. Ann. Rev. Astron. Astrophys. 14, 197–214 (1976).

    ADS  Article  Google Scholar 

  46. Li, D. Summary of the FAST project. In Frontiers in Radio Astronomy and FAST Early Sciences Symposium (eds Qian, L. & Li, D.) 93–97 (ASP Conf. Ser. Vol. 502, Astronomical Society of the Pacific, San Francisco, 2016).

  47. Hirabayashi, H. et al. The VLBI Space Observatory Programme and the radio-astronomical satellite HALCA. Publ. Astron. Soc. Jpn 52, 955–965 (2000).

    ADS  Article  Google Scholar 

  48. Hirabayashi, H. et al. Overview and initial results of the Very Long Baseline Interferometry Space Observatory Programme. Science 281, 1825–1829 (1998).

    ADS  Article  Google Scholar 

  49. Hong, X., Shen, Z., An, T. & Liu, Q. The Chinese space millimeter-wavelength VLBI array—a step toward imaging the most compact astronomical objects. Acta Astronaut. 102, 217–225 (2014).

    ADS  Article  Google Scholar 

  50. Owen, F. N., Eilek, J. A. & Kassim, N. E. M87 at 90 centimeters: a different picture. Astrophys. J. 543, 611–619 (2000).

    ADS  Article  Google Scholar 

  51. Hada, K. et al. Pilot KaVA monitoring on the M87 jet: confirming the inner jet structure and superluminal motions at sub-pc scales. Publ. Astron. Soc. Jpn. 69, 71–80 (2017).

    ADS  Article  Google Scholar 

  52. Dame, T. M., Hartmann, D. & Thaddeus, P. The Milky Way in molecular clouds: a new complete CO survey. Astrophys. J. 547, 792–813 (2001).

    ADS  Article  Google Scholar 

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T.A. thanks the grant supported by the Ministry of Science and Technology of China (2016YFE0100300), the Youth Innovation Promotion Association and FAST Fellowship of Chinese Academy of Sciences. H.I. thanks the grants supported by KAKENHI (16H02167) and the Korea Astronomy and Space Science Institute Commissioning Program. The authors are grateful to the engineering and scientific teams of the EAVN for test experiments. The authors thank Y. Hagiwara for his contribution in preparing the draft, W. Baan, D. Byun, R. Dodson, S. Frey, K. Fujisawa, K. Hada, M. Honma, D.R. Jiang, T. Jung, M. Kino, S.-S. Lee, D. Li, P. Mohan, R.D. Nan, C.S. Oh, Z.H. Qian, M. Rioja, K. Shibata, F.W. Tong, K. Wajima, N. Wang, S.H. Ye, Y. Yonekura and Y.J. Yun for comments on the manuscript and for providing helpful information. B.W.S. is grateful for the support of the National Research Council of Science and Technology, Korea (EU-16-001).

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T.A. coordinated the writing of the paper. All authors have contributed to the EAVN commissioning and the preparation for this Perspective.

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Correspondence to T. An.

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An, T., Sohn, B.W. & Imai, H. Capabilities and prospects of the East Asia Very Long Baseline Interferometry Network. Nat Astron 2, 118–125 (2018).

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