ATCA observations of SiO masers in the Galactic center
  We present the Australia Telescope Compact Array (ATCA) observations of the
SiO masers in the Galactic center in transitions of v=1, J=2--1 at 86 GHz and
v=1, J=1--0 at 43 GHz. Two 86-GHz SiO masers were detected within the central
parsec, and they are associated with IRS 10EE and IRS 15NE, respectively. We
detected eighteen 43-GHz SiO masers within a projected separation of <2 pc from
Sagittarius A* (Sgr A*), among which seven masers are newly discovered from our
observations. This raises the total number of 43-GHz SiO masers within the
central 4 parsecs of the GC region to 22. Simultaneous observations at 86 and
43 GHz showed that the intensity of 43-GHz SiO maser is ~3 times higher than
that of 86-GHz maser in IRS 10EE (an OH/IR star), while the integrated flux of
the SiO maser emission at 43 GHz is comparable with that at 86~GHz in IRS~15NE
(an ordinary Mira variable). These results are consistent with previous
observations of massive late-type stars in the Galaxy in which the 86-GHz SiO
maser is in general weaker than the 43-GHz SiO maser in OH/IR stars, while the
two transitions are comparably strong in Mira stars.
