Journal of The Korean Astronomical Society (천문학회지)

The Korean Astronomical Society (한국천문학회)
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OBSERVATIONS OF $HC_3N$ TOWARD THE SGR B2 MOLECULAR CLOUD

  • MINH Y. C. (Korea Astronomy Observatory) ;
  • KIM HYUN-GOO (Korea Astronomy Observatory)
  • Published : 1998.10.01
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Abstract

We have observed the 10-9 transitions of $HC_3N$ and its $^{13}C$ substitutes ($H^{13}CCCN,\;HC^{13}CCN$, and $HCC^{13}CN$), and the vibration ally excited 12-11 ($v_r=1$) $HC_3N$ transition toward the Sgr B2 molecular cloud. The observed $HC_3N$ emission shows an elongated shape around the Principal Cloud ($\~$4.5 pc in R.A. $\times$ 7.4 pc in Decl.). The optically thin $H^{13}CCCN$ line peaks around the (N) core and we derive the total column density $N(H^{13}CCCN) = 4 {\times}10^{13} cm^{-2}$ at this position. Toward the 2' N cloud which shows the peculiar chemistry, the $HC_3N$ lines show enhancements compared to the extended envelope. The shocks of the 2' N may have resulted in the enhancement of $HC_3N$. The hot component of $HC_3N$ is strongly concentrated around the (N) core and its HPW is $\~$0.9 pc in diameter. We derive the lower limit of the abundance ratio $N(HC_3N)/N(H^{13}CCCN)$ to be larger than 40 in most regions except the (M) and (N) cores. The fractionation processes of $^{13}C $at this region may not be as effective as previously reported.

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References

  1. ApJ v.324 Bally, J.;Stark, A. A.;Wilson, R. W.;Henkel, C.
  2. A&A v.216 Booth, R. S.;Delgado, G.;Hagstrom, M.;Johansson, L.E.B.;Murphy, D.C.
  3. ApJS v.60 Cummins, S.E.;Linke, R.A.;Thaddeus, P.
  4. ApJ v.299 Goldsmith, P. F.;Krotkov, R.;Snell, R. L.
  5. ApJ v.314 Goldsmith, P.G.;Snell, R.;Hasegawa, T.;Ukita, N.
  6. A&A v.280 Gordon, M.A.;Berkermann, U.;Mezger, P.G.;Zylka, R.;Haslam, C.G.T.;Kreysa, E.;Sievers, A.;Lemke, R.
  7. ApJ v.429 Hasegawa, T.;Sato, F.;Whiteoak, J.B.;Miyawaki, R.
  8. ApJS v.53 Herbst, E.
  9. Interstellar Processes(IGH) Irvine, W.M.;Goldsmith, P.F.;Hjalmarson, A.;D.J. Hollenbach(ed.);H.A. Thronson, Jr.
  10. J. Phys. Chem. Ref. Data v.21 Lovas, F.J.
  11. ApJ v.498 Minh, Y.C.;Hjalmarson, A.
  12. Adv. Sp. Res. submitted Minh, Y.C.;Hjalmarson, A.
  13. A&AS, submitted Nummelin, A.(et al.)
  14. ApJ v.201 Scoville, N.Z.;Solomon, P.M.;Penzias, A.A.
  15. Thesis, Univ. of Massachusetts Taylor, D.
  16. ApJ v.300 Thronson, H. A.;Harper, D. A.
  17. A&A v.314 Wilson, T.L.;Snyder, L.E.;Comoretto, G.;Jewell, P.R.;Henkel, C.