SIMBAD references

We present a multiwavelength analysis of a ∼30' x 30' area around the Sh 2-53 region (hereafter S53 complex), which is associated with at least three H II regions, two mid-infrared bubbles (N21 and N22), and infrared dark clouds. The ¹³CO line data trace the molecular content of the S53 complex in a velocity range of 36-60 km s^–1 and show the presence of at least three molecular components within the selected area along this direction. Using the observed radio continuum flux of the H II regions, the derived spectral types of the ionizing sources agree well with the previously reported results. The S53 complex harbors clusters of young stellar objects (YSOs) that are identified using the photometric 2-24 µm magnitudes. It also hosts several massive condensations (3000–30,000 M_☉) that are traced in the Herschel column density map. The complex is found at the junction of at least five molecular filaments, and the flow of gas toward the junction is evident in the velocity space of the ¹³CO data. Together, the S53 complex is embedded in a very similar "hub-filament" system to those reported in Myers, and the active star formation is evident toward the central "hub" inferred by the presence of the clustering of YSOs.