Ratio of N(H₂) and CO line area for ¹²CO and ¹³CO ground state rotational transitions in the southern half of MBM12. The figures are in units of X_Gal = 2 × 10²⁰ cm⁻² (K km s⁻¹)⁻¹. The beam size and linear scale are shown at the bottom left and right respectively. Contours of N(H₂) are shown in red at levels of [1, 2, 5, 8, 10] × 10²¹ cm⁻². The bottom panel shows the PDFs of X(¹²CO) and X(¹³CO).