Signature of an Intermediate-Mass Black Hole in the Central Molecular
  Zone of Our Galaxy
  We mapped the high-velocity compact cloud CO-0.40-0.22 in 21 molecular lines
in the 3 mm band using the Nobeyama Radio Observatory 45 m radio telescope.
Eighteen lines were detected from CO-0.40-0.22. The map of each detected line
shows that this cloud has a compact appearance (d=~3 pc) and extremely broad
velocity width (DV=~100 km/s). The mass and kinetic energy of CO-0.40-0.22 are
estimated to be 10^{3.6} M_sun and 10^{49.7} erg, respectively. The
representative position-velocity map along the major axis shows that
CO-0.40-0.22 consists of an intense region with a shallow velocity gradient and
a less intense high-velocity wing. Here, we show that this kinematical
structure can be attributed to a gravitational kick to the molecular cloud
caused by an invisible compact object with a mass of ~10^5 M_sun. Its
compactness and the absence of counterparts at other wavelengths suggest that
this massive object is an intermediate-mass black hole.
