Three-color composite images of DR18 (8 µm in red, 4.5 µm in green, and 3.6 µm in blue) with different maximum flux levels for three Spitzer/IRAC bands to show the extended emission in a larger FoV (left panel) and the emission details, which are saturated in the left panel, in a zoom-in view (right panel) covering our 5.1′ × 5.1′ target region (outlined by a white square box in the large FoV image). In both images, cyan contour lines represent the combined VLA B+D array 6 cm radio continuum emission from the GLOSTAR survey by levels of 0.35, 0.70, 1.05, 1.40, 1.75, 2.10, 2.45, 2.80, 3.15, and 3.50 mJy/beam. In the zoom-in image, the different color symbols indicate young stellar objects identified by infrared colors (Comerón et al. 2022): yellow squares mark Class I YSOs, light blue diamonds for Class II YSOs, red upside-down triangle for a flat spectrum YSO, purple circles for Class III YSOs, and bright green upside triangles represent transition-disk YSOs. The yellow half-arc line indicates the open shell or the ear-like feature in the infrared emission image.