Journal of The Korean Astronomical Society (천문학회지)

The Korean Astronomical Society (한국천문학회)
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A STUDY OF MOLECULAR CLOUD ASSOCIATED WITH THE H II REGION Sh 156

  • KANG MEEJOO (Department of Astronomy & Space Science, Chungnam National University) ;
  • LEE YOUNGUNG (Korea Astronomy and Space Science Institute, Taeduk Radio Astronomy Observatory)
  • Published : 2005.06.01
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Abstract

We have conducted observations toward the molecular cloud associated with the H II region Sh 156 in $^{13}CO$(J = 1-0), $C^{18}O$(J = 1-0), and CS(J = 2 -1) using the TRAO 14 m telescope. Combining with existing $^{12}CO$(J = 1- 0) data of the Outer Galaxy Survey, we delineated the physical properties of the cloud. We found that there is a significant sign of interaction between the H II region and the molecular gas. We estimated the masses of the molecular cloud, using three different techniques; the most plausible mass is estimated to be $1.37 {\times} 10^5 M_{\bigodot}$, using a conversion factor of $X = 1.9 {\times} 10^{20}\;cm^{-2} (K\;km\;s^{-1})^{-1}$, and this is similar to virial mass estimate. This implies that the cloud is gravitationally bound and in virial equilibrium even though it is closely associated with the H II region. In addition to existing outflow, we found several MSX and IRAS point sources associated with dense core regions. Thus, more star forming activities other than the existing H II region are also going on in this region.

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References

  1. Barbon, R., & Hassan, S. M., 1996, A new study of the young open cluster NGC 7510, A&AS,115, 325
  2. Barlow, M. J., Cohen, M., & Gull, T. R., 1976, Extinction variations in the H II regions Sharpless 156 and 162, MNRAS, 176, 359 https://doi.org/10.1093/mnras/176.2.359
  3. Blair, G. N., Peters, W. L., & vanden Bout, P. A., 1975, Strong molecular line emission associated with small Halpha emission regions, ApJ, 200, 161 https://doi.org/10.1086/181921
  4. Blitz, L., Fich, M., & Stark, A. A., 1982, Catalog of CO radial velocities toward galactic H II regions, ApJS, 49, 183 https://doi.org/10.1086/190795
  5. Cohen, M., & Barlow, M. J., 1973, Infrared Observations of Two Symmetric Nebulae, ApJ, 185, 37 https://doi.org/10.1086/181316
  6. Crampton, D., Georgelin, Y. M., & Georgelin, Y. P., 1978, First optical detection of W51 and observations of new H II regions and exciting stars, A&A, 66, 1
  7. Dickman, R. L., 1978, The ratio of carbon monoxide to molecular hydrogen in interstellar dark clouds, ApJS, 37, 407 https://doi.org/10.1086/190535
  8. Elmegreen, B. G., & Moran, J. M., 1979, Observations of the shock in a region of shock-induced star formation - NGC 281, ApJ, 227, 93 https://doi.org/10.1086/156707
  9. Elmergreen, B. G., & Wang, M., 1987, in Molecular Clouds in the Milky way and External Galaxies, ed. R. L. Dickman, R. L. Snell., & J. S. Young (Berlin: Springer), 240
  10. Fich, M., Treffers, R. R., & Dahl, G. P., 1990, Fabry-Perot H-alpha observations of Galactic H II regions, AJ, 99, 622 https://doi.org/10.1086/115356
  11. Furst, E., Reich, W., Reich, P., & Reif, K., 1990, A Radio Continuum Survey of the Galactic Plane at 11-CENTIMETER Wavelength - Part Three - the Area 76 DEG < L < 240 DEG, A&AS, 85, 691
  12. Heydari-Malayeri, M., Testor, G., & Lortet, M. C., 1980, Interaction of hot stars and the interstellar matter. X - Morphology, excitation, and structure of the bright galactic nebula Sh2-156 /IC 1470/, A&A, 84, 154
  13. Heyer, M. H., Brunt, C., Snell, R. L., Howe, J. E., Schloerb, F. P., & Carpenter, J. M., 1998, The Five College Radio Astronomy Observatory CO Survey of the Outer Galaxy, ApJS, 115, 241 https://doi.org/10.1086/313086
  14. Hodapp, K-W., 1994, A K' imaging survey of molecular outflow sources, ApJS, 94, 615 https://doi.org/10.1086/192084
  15. Hunter, D.A., & Massey, P., 1990, Small Galactic H II regions. I - Spectral classifications of massive stars, AJ, 99, 846 https://doi.org/10.1086/115378
  16. Israel, F. P., 1978, H II regions and CO clouds - The blister model, A&A, 70, 769
  17. Keto, E. R., & Ho, P. T. P., 1989, $NH_3$ observations of compressed postshock molecular gas in ionization-shock fronts around W33, ApJ, 347, 349 https://doi.org/10.1086/168123
  18. Kutner, M. L., & Ulich, B. L., 1981, Recommendations for calibration of millimeter-wavelength spectral line data, ApJ, 250, 341 https://doi.org/10.1086/159380
  19. Lada, C. J., Elmegreen, B. G., Cong, H.-I., & Thaddeus, P., 1978, Molecular clouds in the vicinity of W3, W4, and W5, ApJ, 226, 39 https://doi.org/10.1086/182826
  20. Lee, Y., 1994, Mass estimate of molecular clouds, PKAS, 9(1), 55
  21. Lee, Y., & Jung, J. H., 2003, A molecular cloud complex above the galactic plane. I. Extended CO observations of the NGC 281 region, New Astronomy, 8, 191
  22. Lonsdale, Carol J., & Helou, G., 1985, Cataloged galaxies and quasars observed in the IRAS survey, (Pasadena: Jet Propulsion Laboratory )
  23. Lynds, B. T., & O'Neil, E. J., Jr., 1983, An optical study of IC 1470, ApJ, 265, 803 https://doi.org/10.1086/160725
  24. Roh, D.G., & Jung, J. H., 1999, Characteristics of TRAO 14M Radio Telescope (1999), PKAS, 14, 123
  25. Scoville, N. Z., Yun, M. S., Clemens, D. P., Sanders, D. B., & Waller, W. H., 1987, Molecular clouds and cloud cores in the inner Galaxy, ApJS, 63, 821 https://doi.org/10.1086/191185
  26. Schmidt, M., 1965, in Stars and Stellar Systems, Vol. 5, ed. A. Blaauw and M. Schmidt (Chicago: University of Chicago Press), 513
  27. Smutko, Michael F., & Larkin, James E., 1999, A Morphological Study of Infrared Line Emission in Compact Star-Forming Regions, AJ, 117, 2448 https://doi.org/10.1086/300828
  28. Strong, A. W., & Mattox, J. R., 1996, Gradient model analysis of EGRET diffuse Galactic -ray emission, A&A, 308, L21
  29. Tenorio- Tagle, G., 1979, The gas dynamics of H II regions. I - The champagne model, A&A, 71, 59
  30. Valdettaro, R., Palla, F., Brand, J., Cesaroni, R., Comoretto, G., Di Franco, S., Felli, M., Natale, E., Palagi, F., Panella, D., & Tofani, G., 2001, The Arcetri Catalog of $H_2O$ maser sources: Update 2000, A&A, 368, 845 https://doi.org/10.1051/0004-6361:20000526
  31. Williams S. J., Fuller G. A., & Sridharan T. K., 2004, The circumstellar environments of HMPOs. I: Submillimetre continuum emission, A&A, 417, 115 https://doi.org/10.1051/0004-6361:20031733
  32. Wouterloot, J. G. A., Henkel, C., & Walmsley, C. M., 1989, CO observations of IRAS sources in Orion and Cepheus, A&A, 215, 131
  33. Wu, Y., Wei, Y., Zhao, M., Shi, Y., Yu, W., Qin, S., & Huang, M., 2004, A study of high velocity molecular outflows with an up-to-date sample, A&A, 426, 503 https://doi.org/10.1051/0004-6361:20035767