SiO Maser Survey of Southern IRAS Sources

We have surveyed 163 southern IRAS sources in the SiO $J=2$-$1 v=1$ maser line at 86 GHz, obtaining 38 (22 new and 16 previously known) detections. These detections include 6 stars not previously detected in OH 1612 MHz surveys, and 4 sources assigned incorrect OH radial velocities. The distance reachable in this survey turned out to be about 4 kpc. The local velocity dispersion near the Sun were found to be approximately 30~km~s⁻¹ for these IRAS/SiO sources. A relatively high concentration of the SiO detected sources were found at the area 320∘ < l < 340∘ (toward “Norma tangent”). The estimated distances for these sources suggest that this concentration is spread between 2 and 6 kpc from the Sun, peaking on the Scutum–Crux arm.