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Radial Profiles and Spatial Maps

Center each snapshot on the evolving target and use periodic offsets before rotating or binning particles. For face-on/edge-on maps, define the orientation from a stated stellar or cold-gas angular-momentum/inertia selection and record that selection.

  • gas, stellar, dust, and metal surface density;
  • D/G and D/Z;
  • small-to-large grain mass ratio;
  • carbon fraction;
  • source-tag fractions;
  • mean or median grain radius;
  • extinction-curve slope and \(R_V\); and
  • recent or instantaneous star formation.

Use mass sums for D/G and D/Z:

\[ \mathrm{D/G}=\frac{\sum M_{\rm dust}}{\sum M_{\rm gas}}, \qquad \mathrm{D/Z}=\frac{\sum M_{\rm dust}} {\sum M_{\rm metals,gas}+\sum M_{\rm dust}} \]

State explicitly if a different metal denominator is used.

Apertures and bins

For cross-halo comparison, scaled radii such as \(r/R_{200c}\) control for halo size, while fixed physical radii isolate comparable galactic scales. Both can be scientifically useful, but they should not be mixed in one unlabeled trend. The established single-halo ISM diagnostic uses 20 pkpc; the multi-halo analysis must declare its adopted galaxy aperture.

Require minimum particle or effective-resolution thresholds in radial bins. Sparse bins should be masked or shown with uncertainty rather than interpreted as physical zeros.