Profiles along the spines, where each column denotes a different filamentary arm, as labelled (north-west in red, north-east in blue, north in green and south-east in grey). The origin of each of the spines was defined to begin at the heart of the hub. First row: acceleration due to gravity in SDC13 where the mass was calculated using the H₂ column density map, while a uniform, mean cloud mass was used for the acceleration in the second row. Third row: absolute gradient of the acceleration from row three evaluated at each position over the mean core size of ~0.1 pc. The vertical shaded regions correspond to the positions of the cores along each of the filaments, are ~0.1 pc wide and overplotted by the core ID number in Table 2.