Column Density Maps

Using projections operators in the code for column density, one is performing the integral operation,

\sum n_i dx = \bar{n} L_x

which has the rather strange units of computational number density times computational length. We can not just assume that the resultant product will have units of 1/computational length squared. Thus, we can not simply multiply our projected quantity by lscale^-2 to get units of cm^-2.

Instead, we should multiply it by lscale*nscale. This will give us the correct units for column density, when lscale and nscale are in cgs.

For my specific data, my lscale is 1 pc, and my nscale is 1 (which just means it is in cgs by default). So the quantity the code gives for 'projected column density in computational units', can be thought of as being in pc/cm³. To convert this to 1/cm², multiply by the conversion factor 1pc = 3.08567758 × 10¹⁸ cm.