[CLC]Si[/CLC]O Maser Survey of the Galactic Disk [ITAL]IRAS[/ITAL] Sources. I. [FORMULA][F]15[SUP][j0][/SUP]<l<25[SUP][j0][/SUP][/F][/FORMULA], Near End of the Galactic Bar

A survey has been made in the SiO J = 1-0, v = 1 and 2 transitions (~43 GHz) for the color-selected IRAS sources in the Galactic disk area of 15 ° < l < 25 ° and | b | < 3° with the Nobeyama 45 m telescope. We have detected 67 out of 119 observed sources in SiO masers. Distances to the sources are deduced by the IRAS 12 and 25 μm flux densities and range approximately from 2 to 12 kpc. The lines of sight of this region cross the location of the near end of the bar in the Galaxy. Radial velocities of the detected sources spread between -100 and 200 km s -1 . This range slightly exceeds the possible limits expected from Galactic rotation. A comparison of the SiO with the CO and H I velocity-longitude ( v - l ) diagrams reveals that the overall distribution of the SiO maser sources on the v - l diagram resembles the molecular ring feature. Observational data are compared with the theoretical results of the bar models.