ALMA Band 1 continuum imaging of the ρ Oph W filament. Each image is shown in linear stretch, and x- and y- axis are offset along RA and Dec from J2000 16:25:57.0 −24:20:48.0. (a) Restored image, in natural weighting, after point-source subtraction, with a beam of 8".696×6".436/-86deg (see text), and a noise of 5.55 μJy beam⁻¹. (b) Same as panel a, but before point-source subtraction. The three bright point sources are the young stellar objects SR 4 near the centre, ISO-Oph-17 to the east, and DoAr 21 to the south. The cyan circles are centred on the phase directions of each field and their radii correspond to half the radius of the first Airy null (corresponding to a primary beam attenuation of ~0.34). (c) Deconvolved model image, I^m, after point-source subtraction and with 1"² pixels.