Publications of The Korean Astronomical Society (천문학논총)

The Korean Astronomical Society (한국천문학회)
권호 표지
DOI QR코드

DOI QR Code

IMAGE SIMULATIONS OF THE KVN AND EAST ASIA VLBI FACILITIES WITH A SiO MASER MODEL IMAGE

KVN과 동아시아 VLBI 관측시설을 이용한 SiO 메이저 모델이미지 모의실험

  • Received : 2009.11.30
  • Accepted : 2010.03.03
  • Published : 2010.03.31
Download PDF
⟨ Previous Next ⟩

Abstract

We report results of image simulations of the KVN and VLBI experiments of the KVN with several other East Asia VLBI facilities. To investigate their imaging capability a model-generated image of 7 mm SiO maser emission in Mira variables is used. The resulting simulations show that the joint VLBI experiments of the KVN with East Asia VLBI facilities can produce reasonably good images at 7 mm spectral line experiments. However, there are no apparent differences in peak flux densities and images themselves in the simulations among different combinations of these facilities. In addition, the simulated images of observations which include bigger antennas do not show any expected improvement to the image sensitivity. The small variations in the peak flux density and similar image sensitivity, irrespective of different antenna sizes or numbers of baselines used in the simulations, turn out due to a specific characteristic of the adopted model image. Test simulations using another SiO maser image from R Cas observations prove that the participation of bigger antennas in the VLBI experiments does improve image sensitivity. We confirm the need of additional longer baselines in the experiments of the East Asia VLBI facilities to study very compact maser clumps on sub-milliarcsecond scales.

Keywords

References

  1. 김봉규 등, 2008, 한국우주전파관측망 건설사업(최종년도), 한국천문연구원
  2. 이지윤, 정태현, 2008, SiO MASERS의 VLBA 이미지를 이용한 KVN 이미지 모의실험, 천문학논총, 23, 37(논문 1) https://doi.org/10.5303/PKAS.2008.23.2.037
  3. Boboltz, D. A., Diamond, P. J., & Kemball, A. J., 1997, R Aquarii: First Detection of Circumstellar SiO Maser Proper Motions, ApJ, 487, L147 https://doi.org/10.1086/310896
  4. Boboltz, D. A. & Wittkowski, M., 2005, Joint VLBA /VLTI Observations of the Mira Variable S Orionis, ApJ, 618, 953 https://doi.org/10.1086/426107
  5. Cotton, W. D., Mennesson, B., Diamond, P. J., et al., 2004, VLBA Observations of SiO Masers towards Mira Variable Stars, A&A, 414, 275 https://doi.org/10.1051/0004-6361:20031597
  6. Cotton, W. D., Vlemmings, W., Mennesson, B., et al., 2006, Further VLBA Observations of SiO Masers toward Mira Variable Stars, A&A, 456, 339 https://doi.org/10.1051/0004-6361:20065134
  7. Diamond, P. J. & Kemball, A. J., 2003, A Movie of a Star: Multiepoch Very Long Baseline Array Imaging of the SiO Masers toward the Mira Variable TX Cam, ApJ, 599, 1372 https://doi.org/10.1086/379347
  8. Gray, M. D., Wittkowski, M., Scholz, M., Humphreys, E. M. L., & Ohnaka, K., 2009, SiO Maser Emission in Miras, MNRAS, 394, 51 https://doi.org/10.1111/j.1365-2966.2008.14237.x
  9. Humphreys, E. M. L., Gray, M. D., Yates, J. A., Field, D., Bowen, G. H., & Diamond, P. J., 2002, Numerical Simulations of Stellar SiO Maser Variability. Investigation of the Effect of Shocks, A&A, 386, 256 https://doi.org/10.1051/0004-6361:20020202
  10. Jung, T. -H., Rhee, M. -H., Roh, D. -G., Kim, H. -G., & Sohn, B. -W., 2005, Imaging Simulations for the Korean VLBI Network(KVN), JASS, 22, 1
  11. Li, B., 2009, Status of Shanghi 65 m Radio Telescope, 2009 East Asia VLBI Workshop, Seoul/Korea, http://kvn-web.kasi.re.kr/eavw/program.shtml
  12. Reid, M. J. & Menten, K. M., 1997, Radio Photospheres of Long-Period Variable Stars, ApJ, 476, 327 https://doi.org/10.1086/303614
  13. Wittkowski, M., Boboltz, D. A., Ohnaka, K., Driebe, T., & Scholz, M., 2007, The Mira Variable S Orionis: Relationships between the Photosphere, Molecular Layer, Dust Shell, and SiO Maser Shell at 4 Epochs, A&A, 470, 191 https://doi.org/10.1051/0004-6361:20077168
  14. Yi, Jiyune, 2005, High Resolution Observations of Masers in Star Formation Regions and Evolved Stars, Ph. D. Thesis, Chalmers University of Technology
  15. Yi, Jiyune, Booth, R. S., Conway, J. E., & Diamond, P. J., 2005, SiO Masers in TX Cam. Simultaneous VLBA Observations of Two 43 GHz Masers at Four Epochs, A&A, 432, 531 https://doi.org/10.1051/0004-6361:20041658