a) PACS 70 μm image of the G035.39–00.33 filament; b) PACS 70 μm image of the G035.39–00.33 filament and its surroundings; c) SPIRE 250 μm image of the G035.39–00.33 filament and its surroundings; d) temperature (colour) and column density (contours from 1.5 to 9 by 1.5 × 10²² cm^-2) images. The dense cores with mass  >20 M_⊙ are indicated by black ellipses, those with mass  <20 M_⊙ by white ellipses. The elliptical sizes represent the FWHM sizes at 160  μm. The extent of the IRDC (>3 × 10²² cm^-2) is indicated by a white polygon in b–d.