An SiO maser search off the galactic plane

Abstract

We searched for the SiO J = 1-0, v = 1 and 2 maser lines at ∼ 43 GHz in 277 2MASS/MSX/IRAS sources off the Galactic plane (|b| ≳ 3°), which resulted in 119 (112 new) detections. Among the new detections, two are very faint objects with MSX 12 μm 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° < |b | < 5°) 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° < l < 45° and 3° < |b| < 5°. We also found a group of stars that does not follow to the Galactic rotation. This feature appears in the Galactic disk at l ∼ 27°, and extends more than 15° in the galactic latitude, like a stream of tidal debris from a dwarf galaxy. © 2007. Astronomical Society of Japan.