Close-up view of the total N₂ H⁺ integrated emission in six selected regions along the ISF (see also Fig. 2). From left to right and from top to bottom: (a) OMC-2 FIR 4; (b) OMC-2 FIR 1; (c) OMC-2 FIR 6; (d) OMC-2 South; (e) OMC-1 Ridge; and (f) OMC-1 South. The positions of all the Spitzer protostars (blue triangles; Megeath et al. 2012; Stutz et al. 2013; Furlan et al. 2016) and continuum sources (blue crosses; Teixeira et al. 2016; Kainulainen et al. 2017; Palau et al. 2017) are indicated in all subpanels. Contours are equally spaced every 1 Jy beam⁻¹ km s⁻¹. The beamsize (white solid dot) and the characteristic 0.1 pc scale (white bar) are indicated in the lower corner of each subpanel.