The first detection of the 232 GHz vibrationally excited H2O maser in
  Orion KL with ALMA
  We investigated the ALMA science verification data of Orion KL and found a
spectral signature of the vibrationally excited H2O maser line at 232.68670 GHz
(nu2=1, 5,5,0-6,4,3). This line has been detected in circumstellar envelopes of
late-type stars so far but not in young stellar objects including Orion KL.
Thus, this is the first detection of the 232 GHz vibrationally excited H2O
maser in star-forming regions. The distribution of the 232 GHz maser is
concentrated at the position of the radio Source I, which is remarkably
different from other molecular lines. The spectrum shows a double-peak
structure at the peak velocities of -2.1 and 13.3 km s-1. It appears to be
consistent with the 22 GHz H2O masers and 43 GHz SiO masers observed around
Source I. Thus, the 232 GHz H2O maser around Source I would be excited by the
internal heating by an embedded protostar, being associated with either the
root of the outflows/jets or the circumstellar disk around Source I, as traced
by the 22 GHz H2O masers or 43 GHz SiO masers, respectively.
