SIMBAD references

In the direction of l = 17.°6-19°, the star-forming sites Sh 2-53 and IRAS 18223-1243 are prominently observed, and seem to be physically detached from each other. Sh 2-53 has been investigated at the junction of the molecular filaments, while a larger-scale environment of IRAS 18223-1243 remains unexplored. The goal of this paper is to investigate the star formation processes in the IRAS site (area ∼0.°4 x 0.°4). Based on the GRS ¹³CO line data, two molecular clouds, peaking at velocities of 45 and 51 km s^–1, are found. In the position-velocity plots, a relatively weak ¹³CO emission is detected at intermediate velocities (i.e., 47.5-49.5 km s^–1) between these two clouds, illustrating a link between two parallel elongated velocity structures. These clouds are physically connected in both space and velocity. The MAGPIS data at 20 cm trace free-free continuum emission toward the IRAS 18223-1243 source. Using the Spitzer and UKIDSS photometric data, we have identified infrared-excess young stellar objects (YSOs), and have observed their groups toward the intersection zones of the clouds. IRAS 18223-1243 is also spatially seen at an interface of the clouds. Considering these observational findings, we propose the onset of the collision of two clouds in the IRAS site about 1 Myr ago, which triggered the birth of massive star(s) and the YSO groups. A nonuniform distribution of the GPIPS H-band starlight mean polarization angles is also observed toward the colliding interfaces, indicating the impact of the collision on the magnetic field morphology.