Distance to the Low-velocity Cloud in the Direction of the High-velocity Compact Cloud CO-0.40-0.22

作者：Iwata Yuhei^*; Kato Haruka; Sakai Daisuke; Oka Tomoharu

来源：Astrophysical Journal, 2017, 840(1): 18.

DOI：10.3847/1538-4357/aa67f9

• astrometry
• Galaxy: center
• ISM: clouds
• masers

CO-0.40-0.22 is a peculiar molecular cloud that is compact and has an extraordinary broad velocity width. It is found in the central molecular zone (CMZ) of our Galaxy. In this direction, there is another cloud with an H2O maser spot at a lower velocity. A collision with this low-velocity cloud could be responsible for the broad velocity width of CO-0.40-0.22. We performed phase-referencing very long baseline interferometry (VLBI) astrometry with VERA and detected the annual parallax of the H2O maser spot in the low-velocity cloud to be 0.33 +/- 0.14 mas, which corresponds to a distance of 3.07(-0.91)(+2.22) kpc from the Sun. This implies that the low-velocity cloud is located in the Galactic disk on the near side of the CMZ.

• 出版日期2017-5-1
• 单位中国科学院国家天文台