Water abundance in four of the brightest water sources in the southern sky

Bing-Ru Wang; Lei Qian; Di Li; Zhi-Chen Pan

doi:10.1088/1674-4527/16/3/039

paper

Water abundance in four of the brightest water sources in the southern sky

arXiv:1704.08431 · doi:10.1088/1674-4527/16/3/039

Abstract

We estimated the ortho-{\rm{H $_{2}$ O}} abundances of G267.9--1.1, G268.4--0.9, G333.1--0.4 and G336.5--1.5, four of the brightest ortho-{\rm{H $_{2}$ O}} sources in the southern sky observed by the Submillimeter Wave Astronomy Satellite (ortho-{\rm{H $_{2}$ O}} 1 $_{10}$ -- 1 $_{01}$ line, 556.936~GHz). The typical molecular clumps in our sample have H $_{2}$ column densities of $1 0^{22}$ to $1 0^{23}$ {\,}cm $^{- 2}$ and ortho-{\rm{H $_{2}$ O}} abundances of 10 $^{- 10}$ . Compared with previous studies, the ortho-{\rm{H $_{2}$ O}} abundances are at a low level, which can be caused by the low temperatures of these clumps. To estimate the ortho-{\rm{H $_{2}$ O}} abundances, we used the CS $J = 2 \to 1$ line (97.98095~GHz) and CS $J = 5 \to 4$ (244.93556~GHz) line observed by{ the} Swedish-ESO 15\,m Submillimeter Telescope (SEST) to calculate the temperatures of the clumps and the 350~$\upmu$m dust continuum observed by{ the} Caltech Submillimeter Observatory (CSO) telescope to estimate the H $_{2}$ column densities. The observations of {\rm{N $_{2}$ H $^{+}$ }} ( $J = 1 \to 0$ ) for these clumps were also acquired by SEST and the corresponding abundances were estimated. The {\rm{N $_{2}$ H $^{+}$ }} abundance in each clump shows a common decreasing trend toward the center and {a} typical abundance range from 10 $^{- 11}$ to 10 $^{- 9}$ .

Published in RAA. 11 figures

Water abundance in four of the brightest water sources in the southern sky

Abstract

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