The excitation of H2O masers usually needs very high density gas,hence it can serve as a marker of dense gas in HⅡ region. We selected a sample of H2O maser sources from Plume et al. （four with, and four without det...The excitation of H2O masers usually needs very high density gas,hence it can serve as a marker of dense gas in HⅡ region. We selected a sample of H2O maser sources from Plume et al. （four with, and four without detected CS（J = 7 - 6） emission）, and observed them in ^13CO（J=1-0） and C^18O （J=1-0）. C^18O （J=1-0） emission was detected only in three of the sources with detected CS（J=7-6） emission. An analysis combined with some data in the literature suggests that these dense cores may be located at different evolutionary stages. Multi-line observation study may provide us clues on the evolution of massive star forming regions and the massive stars themselves.展开更多
We made the first CO（1-0） mapping to SNR G21.8-0.6 and SNR G32.8-0.1, both associated with OH 1720MHz maser. Based on the morphological correspondence and velocity and position agreement between the radio remnant an...We made the first CO（1-0） mapping to SNR G21.8-0.6 and SNR G32.8-0.1, both associated with OH 1720MHz maser. Based on the morphological correspondence and velocity and position agreement between the radio remnant and the CO clouds, we tentatively identify the clouds that are respectively interacting with the two SNRs.展开更多
基金Supported by the National Natural Science Foundation of China.
文摘The excitation of H2O masers usually needs very high density gas,hence it can serve as a marker of dense gas in HⅡ region. We selected a sample of H2O maser sources from Plume et al. （four with, and four without detected CS（J = 7 - 6） emission）, and observed them in ^13CO（J=1-0） and C^18O （J=1-0）. C^18O （J=1-0） emission was detected only in three of the sources with detected CS（J=7-6） emission. An analysis combined with some data in the literature suggests that these dense cores may be located at different evolutionary stages. Multi-line observation study may provide us clues on the evolution of massive star forming regions and the massive stars themselves.
基金Supported by the National Natural Science Foundation of China.
文摘We made the first CO（1-0） mapping to SNR G21.8-0.6 and SNR G32.8-0.1, both associated with OH 1720MHz maser. Based on the morphological correspondence and velocity and position agreement between the radio remnant and the CO clouds, we tentatively identify the clouds that are respectively interacting with the two SNRs.
