Indication of Another Intermediate-mass Black Hole in the Galactic
  Center
  We report the discovery of molecular gas streams orbiting around an invisible
massive object in the central region of our Galaxy, based on the
high-resolution molecular line observations with the Atacama Large
Millimeter/submillimeter Array (ALMA). The morphology and kinematics of these
streams can be reproduced well through two Keplerian orbits around a single
point mass of $(3.2 \pm 0.6)\times 10^4 \ M_\odot$. We also found ionized gas
toward the inner part of the orbiting gas, indicating dissociative shock and/or
photoionization. Our results provide new circumstantial evidences for a
wandering intermediate-mass black hole in the Galactic center, suggesting also
that high-velocity compact clouds can be probes of quiescent black holes abound
in our Galaxy.
