Journal of The Korean Astronomical Society (천문학회지)

The Korean Astronomical Society (한국천문학회)
권호 표지
DOI QR코드

DOI QR Code

RENOVATION OF SEOUL RADIO ASTRONOMY OBSERVATORY AND ITS FIRST MILLIMETER VLBI OBSERVATIONS

  • Naeun, Shin (Department of Physics and Astronomy, Seoul National University) ;
  • Yong-Sun, Park (Department of Physics and Astronomy, Seoul National University) ;
  • Do-Young, Byun (Korea Astronomy and Space science Institute) ;
  • Jinguk, Seo (Department of Physics and Astronomy, Seoul National University) ;
  • Dongkok, Kim (Department of Physics and Astronomy, Seoul National University) ;
  • Cheulhong, Min (Department of Physics and Astronomy, Seoul National University) ;
  • Hyunwoo, Kang (Korea Astronomy and Space science Institute) ;
  • Keiichi, Asada (Academia Sinica Institute of Astronomy and Astrophysics) ;
  • Wen-Ping, Lo (Academia Sinica Institute of Astronomy and Astrophysics) ;
  • Sascha, Trippe (Department of Physics and Astronomy, Seoul National University)
  • Received : 2022.10.16
  • Accepted : 2022.11.22
  • Published : 2022.12.31
Download PDF
⟨ Previous Next ⟩

Abstract

The Seoul Radio Astronomy Observatory (SRAO) operates a 6.1-meter radio telescope on the Gwanak campus of Seoul National University. We present the efforts to reform SRAO to a Very Long Baseline Interferometry (VLBI) station, motivated by recent achievements by millimeter interferometer networks such as Event Horizon Telescope, East Asia VLBI Network, and Korean VLBI Network (KVN). For this goal, we installed a receiver that had been used in the Combined Array for Research in Millimeter-wave Astronomy and a digital backend, including an H-maser clock. The existing hardware and software were also revised, which had been dedicated only to single-dish operations. After several years of preparations and test observations in 1 and 3-millimeter bands, a fringe was successfully detected toward 3C 84 in 86 GHz in June 2022 for a baseline between SRAO and KVN Ulsan station separated by 300 km. Thanks to the dual frequency operation of the receiver, the VLBI observations will soon be extended to the 1 mm band and verify the frequency phase referencing technique between 1 and 3-millimeter bands.

Keywords

Acknowledgement

The authors gratefully acknowledge the contribution of Jongho Park for providing a code of the 3D plot of fringes and a kind explanation. We are grateful to the staff of the KVN who helped to operate the array and to correlate the data. The KVN and a high-performance computing cluster are facilities operated by the KASI. The KVN observations and correlations are supported through the high-speed network connections among the KVN sites provided by the KREONET, which is managed and operated by the KISTI. This work was supported partially by National Research Foundation of Korea grant funded by the Korean government (MEST) (No. 2019R1A6A1A10073437 and 2022R1F1A1075115) and partially by KASI under the R&D program (Project No. 2022-1-860-03) supervised by the Ministry of Science and ICT.

References

  1. Algaba, J.-C., Zhao, G.-Y., Lee, S.-S., et al. 2015, Interferometric monitoring of Gamma-Ray bright Active Galactic Nuclei II: Frequency Phase Transfer, JKAS, 48, 237
  2. Byun, D., & Yun, Y.-Z. 2002, Development of control softwares for the SRAO 6-meter telescope based on PCs running Linux, Exp. Astron., 14, 183 https://doi.org/10.1023/b:expa.0000009967.00716.98
  3. The Event Horizon Telescope Collaboration, Akiyama, K., Alberdi, A., Alef, W., et al. 2019, First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole, ApJL, 875, L1 https://doi.org/10.3847/2041-8213/ab0ec7
  4. Hudson, J. 1998, Ray-tracing the BIMA reflectors, BIMA Memoranda Series, No. 64
  5. Hull, C., & Plambeck, R. 2015, The 1.3 mm full-stokes polarization system at CARMA, J. Astron. Instrum., 4, 1550005 https://doi.org/10.1142/S2251171715500051
  6. Koo, B., Park, Y.-S., Hong, S., et al. 2003, Performance of the SRAO 6-meter radio telescope, JKAS, 36, 43
  7. Lee, S.-S., Byun, D.-Y., Park, Y.-S., et al. 2003, Surface Adjustment of the SRAO 6-M Antenna Based on NearField Radio Holography at 86 GHz, International journal of infrared and millimeter waves, 24, 1687 https://doi.org/10.1023/A:1026039402404
  8. Lee, J.-W., Kim, C.-H., Kang, H., et al. 2013, Development of 230 GHz radio receiver system for SRAO, JKAS, 46, 225
  9. Oh, S.-J., Yeom, J.-H., Roh, D.-K., et al. 2017, A Study on the Test Results of 32 Gbps Observing System for Wideband VLBI Observation, Journal of the institute of signal processing and systems, 18, 13
  10. Ogawa, M., Li, R., & Hashimoto, T. 1991, Thermal conductivities of magnetic intermetallic compounds for cryogenic regenerator, Cryogenics, 31, 405 https://doi.org/10.1016/0011-2275(91)90198-6
  11. Park, J., Kam, M., Trippe, S., et al. 2018, Revealing the Nature of Blazar Radio Cores through Multifrequency Polarization Observations with the Korean VLBI Network, ApJ, 860, 112 https://doi.org/10.3847/1538-4357/aac490
  12. Plambeck, R., Thatte, N., & Sykes, P. 1992, A 4K Gifford-Mcmahon refrigerator for radio astronomy, 7th International cryocooler conference proceeding, 2, 401
  13. Rioja, M. J., Dodson, R., Malarecki, J., et al. 2011, Exploration of Source Frequency Phase Referencing Techniques for Astrometry and Observations of Weak Sources with High Frequency Space Very Long Baseline Interferometry, AJ, 142, 157 https://doi.org/10.1088/0004-6256/142/5/157
  14. Rioja, M. J., Dodson, R., Jung, T., et al. 2014, Verification of the Astrometric Performance of the Korean VLBI Network, Using Comparative SFPR Studies with the VLBA at 14/7 mm, AJ, 148, 84 https://doi.org/10.1088/0004-6256/148/5/84
  15. Vertatschitsch, L., Primiani, R., Young, A., et al. 2015, R2DBE: A Wideband Digital Backend for the Event Horizon Telescope, PASP, 127, 1226 https://doi.org/10.1086/684513
  16. Wajima, K., Kino, M., & Kawakatu, N. 2020, Constraints on the Circumnuclear Disk through Free-Free Absorption in the Nucleus of 3C 84 with KaVA and KVN at 43 and 86 GHz, ApJ, 895, 35 https://doi.org/10.3847/1538-4357/ab88a0