The IRAC color composite image of the G351.77-0.53 filamentary region, where the 8.0 μm, 5.6 μm, and 3.6 μm are shown in red, green, and blue, respectively. The orange contour shows the coverage of the 3 mm data ALMA-IMF Large Program observations. The white contour represents the ATLASGAL emission (850 μm) at 0.62 Jy beam⁻¹. The dominant central closed contour indicates the Mother Filament discussed below (also referred to as the “G351 filament” in Reyes-Reyes et al. 2024). This filament is also observed in NIR extinction and submillimeter emission. In its densest part, the star formation activity is revealed by strong NIR emission.