This redoes the "S-curve" calculation originally done by Krolick, McKee, & Tarter (1981; ApJ, 249, 422), The gas density is varied between 101 and 1012 cm-3. It is exposed to the cosmic background and an AGN continuum. The output file hazy_kmt.txt gives the log of the temperature, the temperature (K), and pressure.
The x-axis is the log of the density, and the y-axis is the gas pressure.
The same data is plotted below but with different ratios in the more common form of the S curve. The x-axis is the log of the ratio of the ionization parameter to the temperature and the y axis is the log of the temperature. This plot shows the effects of several of the dielectronic recombination data that are available within the code. Chakravorty et al (2008, MNRAS, 384L, 24, available here) discuss how the DR rates change the nature of the S curve.
last modified 19 July, 2008