Journal of The Korean Astronomical Society (천문학회지)

The Korean Astronomical Society (한국천문학회)
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KVNCS: 2. The Fringe Survey of New Candidates for VLBI Calibrators in the K Band

  • Received : 2023.05.14
  • Accepted : 2023.07.04
  • Published : 2023.12.30
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Abstract

The main goal of the Korean VLBI Network Calibrator Survey (KVNCS) is to expand the VLBI calibrators catalog for KVN, KaVA (KVN and VERA Array), EAVN (East-Asian VLBI Network), and other extended regions. The second KVNCS (KVNCS2) aimed to detect VLBI fringes of new candidates for calibrators in the K band. Out of the 1533 sources whose single-dish flux density in the K band was measured with KVN telescopes (Lee et al. 2017), 556 sources were observed with KVN in the K band. KVNCS2 confirmed the detection of VLBI fringes of 424 calibrator candidates over a single baseline. All detected sources had a high Signal-to-Noise Ratio (SNR) of >25. Finally, KVNCS2 confirmed 347 new candidates as VLBI calibrators in the K band, resulting in a 5% increase in the sky coverage compared to previous studies. The spatial distribution was quasi-uniform across the observable region (Dec. > -32.5°). In addition, the possibility as calibrator candidates for the detected sources was checked, using an analysis of the flux-flux relationship. Ultimately, the KVNCS catalog will not only become the VLBI calibrator list but is also useful as a database of compact radio sources for astronomical studies.

Keywords

Acknowledgement

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 KASI (Korea Astronomy and Space Science Institute). The KVN observations and correlations are supported through the high-speed network connections among the KVN sites provided by KREONET (Korea Research Environment Open NETwork), which is managed and operated by KISTI (Korea Institute of Science and Technology Information). Thanks to KaVA (recently EAVN) Science Working Group, which supported the first KVNCS imaging survey (KVNCS3.1) proposal.

References

  1. An, T., Wang, A., Zhang, Y., et al. 2022, MNRAS, 511, 4572
  2. Angioni, R., Ros, E., Kadler, M., et al. 2019, A&A, 627, A148
  3. Beasley, A. J., & Conway, J. E. 1995, in ASPCS, Vol. 82, Very Long Baseline Interferometry and the VLBA, ed. J. A. Zensus, P. J. Diamond, & P. J. Napier, 327
  4. Charlot, P., Boboltz, D. A., Fey, A. L., et al. 2010, AJ, 139, 1713
  5. Charlot, P., Jacobs, C. S., Gordon, D., et al. 2020, A&A, 644, A159
  6. de Witt, A., Jacobs, C. S., Gordon, D., et al. 2023, AJ, 165, 139
  7. Deller, A. T., Brisken, W. F., Phillips, C. J., et al. 2011, PASP, 123, 275
  8. Desai, K. 1998, in AIPS memo 101
  9. Dodson, R., Rioja, M. J., Jung, T.-H., et al. 2014, AJ, 148, 97
  10. Fomalont, E. B., Petrov, L., MacMillan, D. S., Gordon, D., & Ma, C. 2003, AJ, 126, 2562
  11. Gordon, D., Jacobs, C., Beasley, A., et al. 2016, AJ, 151, 154
  12. Han, S.-T., Lee, J.-W., Kang, J., et al. 2008, Int. j. infrared millim. waves, 29, 69
  13. Jung, T. 2018, in 14th European VLBI Netw. Symp. & Users Meet. (EVN 2018), 104
  14. Jung, T., Sohn, B. W., Kobayashi, H., et al. 2011, PASJ, 63, 375
  15. Kovalev, Y. Y., Petrov, L., Fomalont, E. B., & Gordon, D. 2007, AJ, 133, 1236
  16. Krezinger, M., Perger, K., Gabanyi, K. E., et al. 2022, ApJS, 260, 49
  17. Lanyi, G. E., Boboltz, D. A., Charlot, P., et al. 2010, AJ, 139, 1695
  18. Lee, J. A. 2017, PhD thesis, Univ. of Sci. and Technol. (UST), Repub. of Korea
  19. Lee, J. A., Sohn, B. W., Jung, T., Byun, D.-Y., & Lee, J. W. 2017, ApJS, 228, 22
  20. Lee, S.-S., Byun, D.-Y., Oh, C. S., et al. 2011, PASP, 123, 1398
  21. Lee, S.-S., Petrov, L., Byun, D.-Y., et al. 2014, AJ, 147, 77
  22. Lee, S.-S., Oh, C. S., Roh, D.-G., et al. 2015, JKAS, 48, 125
  23. Lee, S.-S., Wajima, K., Algaba, J.-C., et al. 2016, ApJS, 227, 8
  24. Lobanov, A. P., Krichbaum, T. P., Witzel, A., & Zensus, J. A. 2006, PASJ, 58, 253
  25. Ma, C., Arias, E. F., Eubanks, T. M., et al. 1998, AJ, 116, 516
  26. Petrov, L. 2012, MNRAS, 419, 1097
  27. Petrov, L., Honma, M., & Shibata, S. M. 2012, AJ, 143, 35
  28. Petrov, L., Kovalev, Y. Y., Fomalont, E., & Gordon, D. 2005, AJ, 129, 1163
  29. Petrov, L., Kovalev, Y. Y., Fomalont, E. B., & Gordon, D. 2006, AJ, 131, 1872
  30. Petrov, L., Kovalev, Y. Y., Fomalont, E. B., & Gordon, D. 2008, AJ, 136, 580
  31. Petrov, L., Kovalev, Y. Y., Fomalont, E. B., & Gordon, D. 2011, AJ, 142, 35
  32. Rioja, M. J., Dodson, R., Jung, T., & Sohn, B. W. 2015, AJ, 150, 202
  33. Traianou, E. T. 2020, PhD thesis, Andreas Eckart Univ. of Cologne, Germany
  34. Zhao, G.-Y., Algaba, J. C., Lee, S. S., et al. 2018, AJ, 155, 26
  35. Zhao, G.-Y., Jung, T., Sohn, B. W., et al. 2019, JKAS, 52, 23