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 \lesssim 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 \sim 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 .