An SiO Maser Search off the Galactic Plane

Abstract

Abstract We searched for the SiO $J=1$-0, $v= 1$ and 2 maser lines at $\sim 43$ GHz in 277 2 MASS/MSX/IRAS sources off the Galactic plane ($\vert b\vert\gtrsim 3^{\circ}$), which resulted in 119 (112 new) detections. Among the new detections, two are very faint objects with MSX 12$\mu$m flux densities below 2 Jy. These are likely to be O-rich AGB-stars associated with dwarf-galaxy tidal tails. The sample also includes medium bright MSX objects at moderately high galactic latitudes ($3^{\circ}<\vert b\vert<5^{\circ}$) and in the IRAS gap at higher latitudes. A signature of a warp of the inner Galactic disk is found for a disk subsample. This warp appears relatively strongly in the area of $0^{\circ}<l<45^{\circ}$ and $3^{\circ}<\vert b\vert<5^{\circ}$. We also found a group of stars that does not follow to the Galactic rotation. This feature appears in the Galactic disk at $l\sim 27^{\circ}$, and extends more than $15^{\circ}$ in the galactic latitude, like a stream of tidal debris from a dwarf galaxy.