The color scale presents a Herschel 250 μm continuum image of the Orion B region. Contours are from the integrated intensity maps of ¹³CO (middle left panel) and C¹⁸O (middle right panel). The contour levels for the ¹³CO integrated intensity map are [1, 3, 5, 7, 9, 11] K km s⁻¹ and those for the C¹⁸O integrated intensity map are [0.25, 0.75, 1, 1.5, 2.2, 3.5, 6] K km s⁻¹. Panels (a)–(f) show representative spectra of ¹³CO (black line) and C¹⁸O (blue line) at the central positions marked with green dots in the middle left panel and the middle right panel. In panel (a)–(f), the C¹⁸O spectrum is scaled up by a factor of 2 and shifted by –1 in intensity. The gray and cyan horizontal lines represent baselines of the ¹³CO and C¹⁸O spectra, respectively.