@article{9d6f1ad0a63d428d8fc97b8d944dc76b,
title = "An energetic high-velocity compact cloud: CO-0.31+0.11",
abstract = "We have discovered an energetic high-velocity compact cloud CO-0.31+$0.11 in the central molecular zone of our Galaxy. CO-0.31+$0.11 is located at a projected distance of ∼45 pc from the Galactic nucleus Sgr A∗. It is characterized by its compact spatial appearance (d 4 pc), extremely broad velocity width (ΔV > 100 km s-1), and high CO J = 3-2/J = 1-0 intensity ratio. The total gas mass and kinetic energy are estimated as approximately 104, M⊙ and 1051 erg, respectively. Two expanding bubble-like structures are found in our HCN J = 1-0 map obtained with the Nobeyama Radio Observatory 45 m telescope. In the longitude-velocity maps, CO-0.31+$0.11 exhibits an asymmetric V shape. This kinematical structure can be well fitted by Keplerian motion on an eccentric orbit around a point mass of 2× 105 M⊙. The enhanced CO J = 3-2/J = 1-0 ratio is possibly attributed to the tidal compression during the pericenter passage. The model suggests that a huge mass is packed within a radius of r < 0.1 pc. The huge mass, compactness, and absence of luminous stellar counterparts may correspond to a signature of an intermediate-mass black hole (IMBH) inside. We propose a formation scenario of CO-0.31+0.11 in which a compact cloud has gravitationally interacted with an IMBH and a bipolar molecular outflow was driven by the past activity of the putative IMBH.",
keywords = "Galaxy: center, ISM: clouds, ISM: kinematics and dynamics, ISM: molecules",
author = "Shunya Takekawa and Tomoharu Oka and Sekito Tokuyama and Kyosuke Tanabe and Yuhei Iwata and Shiho Tsujimoto and Mariko Nomura and Yukihiro Shibuya",
note = "Funding Information: This study is based on observations by the Nobeyama Radio Observatory (NRO) 45 m telescope and the James Clerk Maxwell Telescope (JCMT). The NRO is a branch of the National Astronomical Observatory of Japan, National Institutes of Natural Sciences. The JCMT is operated by the East Asian Observatory on behalf of the National Astronomical Observatory of Japan, Academia Sinica Institute of Astronomy and Astrophysics, the Korea Astronomy and Space Science Institute, the National Astronomical Observatories of China, and the Chinese Academy of Sciences (grant no. XDB09000000), with additional funding support from the Science and Technology Facilities Council of the United Kingdom and participating universities in the United Kingdom and Canada. We are grateful to the NRO for their excellent support of the 45 m telescope observations. We also acknowledge the JCMT Galactic Plane Survey (JPS) team for providing us with the excellent data. We thank Dr. S. Nakashima for comments and suggestions on the handling of X-ray data. We are also grateful to the anonymous referee for helpful comments and suggestions that improved this paper. This study was supported by a Grant-in-Aid for Research Fellow from the Japan Society for the Promotion of Science (15J04405). Publisher Copyright: {\textcopyright} 2019 The Author(s) 2019. Published by Oxford University Press on behalf of the Astronomical Society of Japan.",
year = "2019",
month = dec,
day = "1",
doi = "10.1093/pasj/psz027",
language = "English",
volume = "71",
journal = "Publications of the Astronomical Society of Japan",
issn = "0004-6264",
publisher = "Astronomical Society of Japan",
}