Skip to main content
. Author manuscript; available in PMC: 2015 Nov 11.
Published in final edited form as: Astrophys J. 2015 Oct 10;812(1):75. doi: 10.1088/0004-637X/812/1/75

Figure 16.

Figure 16

(a) Simplified geometry (not to scale) of OMC 1 (red, molecular gas and dust), the FUV-illuminated cloud face (blue, dominating the [C ii] emission), dense ionized gas in the H ii region surrounding the Trapezium (green), and the atomic Veil (shaded, producing foreground H i absorption). The observed [C ii] emission, I[CII], reaches the observer (to the left) almost unattenuated. At a given position, the observed ~160 μm dust emission is B160(Td)(1 – e−τd,160), where τd,160 is the ~160 μm dust opacity along the entire line of sight. (b) Mixed C+ and dust grains along the line of sight. In this case I[CII]=I0,[CII](1 – e−τd,160)/τd,160, where I0,[CII] is the unattenuated [C ii] emission. (c) [C ii] sources embedded behind large columns of dust. In this case I[CII]=I0,[CII] e−τd,160.