3 mm band line survey toward the high-velocity compact cloud CO-0.40-0.22

T. Oka, K. Tanaka, S. Matsumura, K. Miura, S. Takekawa, Y. Takahata, Akihiko Nishino

Research output: Contribution to journalArticlepeer-review


High-velocity compact clouds (HVCCs) are a population of molecular clouds which have compact appearance (d < 10 pc) and large velocity width (Δ V > 50 km s-1), and are found in the central molecular zone of our Galaxy. We performed a 3 mm band line survey toward CO-0.40-0.22, a spatially unresolved HVCC with an extremely large velocity width (Δ V ≃ 90 km s-1), using the Mopra 22 m telescope. We surveyed the frequency range between 76 GHz and 116 GHz with a 0.27 MHz frequency resolution. We detect at least 54 lines from 32 molecules. Many line profiles show a prominent peak at vLSR ~ 70 km s-1 with very large velocity width, indicating they are emitted by the HVCC. Detections of largish molecules are indicative of non-equilibrium chemistry. We extracted some prominent lines based on velocity structure, intensity ratios, and PCA analyses. Shock diagnostic lines (SiO, SO, CH3OH, HNCO) and dense gas probes (HCN, HCO+) appear to be prominent. Excitation analysis of CH3OH lines show an enhancement in Trot in the negative high-velocity end of the profile. These results suggest that CO-0.40-0.22 has experienced a shock, acceleration, compression, and heating in the recent past.

Original languageEnglish
Pages (from-to)202-204
Number of pages3
JournalProceedings of the International Astronomical Union
Issue numberS303
Publication statusPublished - 2014 May


  • Galaxy: center
  • ISM: clouds
  • ISM: molecules
  • radio lines: ISM

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Astronomy and Astrophysics
  • Nutrition and Dietetics
  • Public Health, Environmental and Occupational Health
  • Space and Planetary Science


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