Diagnostics Diagrams Tool: Ratio-Ratio Diagrams

Specific column density ratios may be used as diagnostic probes of the ionization state, temperature, and metallicity in radiatively cooling gas. For CIE, the ion fractions are independent of the metallicity, and the column density ratios depend only on the gas temperature. However, for non-equilibrium cooling the ion fractions also depend on Z, and hence so do the column density ratios.

Online Tool:
Select ratio to be displayed on y-axis:

      this will take ~2 minutes...


Select ratio to be displayed on x-axis:

In the figures generated here (see, for example, figure 9 in text) we display "cooling trajectories" for two ionic ratios. Use the drop-down lists to select the ratios to be displayed along the x- and y-axes. Use the buttons on the right to select whether results should be displayed for isochoric or isobaric cooling. Then press "Submit Query". Results would appear in a couple of minutes.

The gas temperature is represented by color along the curves, from hot (red) to cool (blue). Panel (a) shows the behavior for CIE, for which the results are independent of Z. Panels (b)-(f) are for non-equilibrium isochoric cooling, for Z from 10-3 to 2. The CIE trajectory is reproduced as the grey curves in panels (b)-(f).

Constructed: June 2006, Orly Gnat