Projected magnetic field of the O-star model at a time of t = 200 000 yr, showing the full simulation cube (extent of 4 pc along each axis). The horizontal and vertical graph axes correspond to the simulation of x- and y-axes, respectively. The three grey-scale images (top-left, top-right and bottom-right panels) show the line-of-sight integral of the line-of-sight component of the magnetic field, weighted by the ionized (top-left), neutral (top-right) or molecular (bottom-right) gas density. The superimposed red vectors indicate the magnitude and direction of the line-of-sight integral of the plane-of-sky components of the magnetic field, using the same weightings. The integrals of the plane-of-sky components were carried out in a Stokes QU frame, as described in Appendix A. Blue contour lines show the column density of molecular gas, to aid comparison between the panels. The bottom-left panel shows a composite image of the column densities of molecular (red), neutral (green) and ionized (blue) gas. The normalization varies between the panels. For the column densities (bottom-left panel and contours), the maximum plotted values in units of H nuclei per cm2 are 3.7 × 1021 (ionized), 5.1 × 1022 (neutral) and 1.3 × 1023 (molecular). For the projected magnetic fields, the maximum plotted values in units of μG times H nuclei per cm2 are 5.2 × 1022 (ionized, top left), 2.1 × 1024 (neutral, top right) and 1.7 × 1024 (molecular, bottom right).
