From: vanhoof@cita.utoronto.ca Sent: Monday, July 26, 1999 6:58 PM Hi Gary, Below I will go through the changes I made in version 84 of Cloudy. I will use the same sequence as in the appendix of my thesis. This file is intended as an addition to the discussion in my thesis and both should be read together. For each command I will indicate my assessment of the importance of the command. 1. distance 21.85 [vary] Very useful for allowing the user to supply fluxes in natural units (i.e. as observed) and allowing Cloudy to generate output that is normalized in a more natural way (i.e. spectra and line fluxes normalized at earth distance). This command is necessary when one wants to optimize an observed flux and simultaneously wants to vary the inner radius. Priority: high 2. dlaw [vary] At present it is not possible to use the keyword vary, although this may very well be useful. Priority: high 3. dtable [use full range] Is implemented as "dlaw table". However the option "full range" is not implemented. This sets the inner and outer radius of the nebula to the start and end radius supplied in the table. This is convenient when the table is produced by an external program and the inner and outer radius may vary from run to run. Priority: medium 4. element helium 11.02 Is mostly implemented in Cloudy 90. However the normalization of the abundance scale cannot be altered, although several normalizations are in use. Priority: high 5. flunit herz [at earth distance] Allows the user to choose other flux units for the spectrum and to normalize fluxes at the earths distance. See also point 1. Priority: high 6. frunit micron Allows the user to choose the frequency unit for his plot 7. grains .... [log], [vary] The keywords log and vary are not included now. Priority: high 8. minimum electron temperature 10K Was needed in Cloudy 84 to assure stability far out in the cold part of the nebula. I am not sure if it is still needed in Cloudy 93 Priority: ?? 9. optimize amoeba No action necessary. 10. optimize angular diameter Combined with the distance, this allow further constraints on the model. Priority: high. 11. optimize color temperature Was introduced when optimizing on IRAS fluxes introduced unstable behavior. Was later abandoned again. Priority: low. 12. optimize continue Is already implemented for optimize_phymir. It could also be implemented for the other optimizers. Priority: low. 13. optimize far-infrared flux Is roughly similar to optimizing on GraT 0 (although not completely, this command includes all emission at IR wavelengths, not just grain emission). See also point 11. Priority: low. 14. optimize flux 3 cm 6 mJy Very useful for optimizing continuum fluxes, e.g. IR grain emission or radio flux. Priority: high. 15. optimize intensity -12.26 Different normalization, see point 1. Priority: high. 16. optimize lines: IRAS 60 .... All kinds of photometric bands were added to Cloudy 84. These are very informative by themselves and probably should be added to Cloudy. I also allowed for the possibility to optimize on fluxes observed in these bands, but found that to be less useful (although not useless). It can introduce instabilities because the code can exchange continuum flux for line flux. This can lead to absurd abundances. Priority: high (for inclusion in output) low to medium (for optimizing) 17. optimize optimize_phymir Already included. 18. optimize tolerance Already changed. 19. plot commands They were very useful, but it is not clear whether they are suitable for distribution since my plot system is based on idl. Priority: low 20. print verbose The default and the exception for printing every iteration/only the last iteration is switched. A matter of taste... Priority: low. 21. punch emissivity Very useful when you want to use a separate code which does proper radiative transport of diffuse continua in optically thick conditions. I have a code which does this (neglecting scattering). Priority: medium 22. punch extended spectrum Is automatically implemented now with the extension of the radio continuum in Cloudy. Hence no action is necessary. 23. rfac 3. Was introduced to solve problems with the "radius 17.0 17.5 vary" command (the optimizer could let the inner radius go outside the outer radius). Apart from this problem, the command is obsolete now. Priority: low. 24. runit parsec Allows the user to chose a radius unit for the punch output. See also point 5 and 6. Priority: high 25. set drmax 0.01 relative Prevent the code from taking very big steps outwards. Allows for a more precise integration outwards and may make the chi^2 function smoother when optimizing. Priority: medium 26. silent Turn off all optimizer output for intermediate iterations. Only the initial messages and the final model are printed. Useful for people with limited disk space (they still exist !). Priority: medium 27. single iteration Is like the "no vary" command, except that it produces the chi^2 information at the end of the file. Useful for doing a short test of the input file. Using "optimize iterations 0" doesn't work, since the number is defaulted to 1 and therefore the model is executed twice. The command "no vary" could be altered to include this possibility. Priority: medium 28. stop flux at 5.9 cm 93 mJy I do not use it at the moment. I am not sure whether it is useful. Priority: low 29. stop [ionized] mass 0.2 I do not use it at the moment. I am not sure whether it is useful. Priority: low 30. stop photometry IRAS 60 23 Jy I use this command for defining an outer radius in the neutral zone, for lack of anything better... Could be altered to something like "stop continuum flux at 60 micron 23 Jy" which would be easier to implement. Priority: high 31. sublimation radius 17.25 Since Cloudy allows for a varying D/G ratio as a function of radius, this is command is obsolete now. 32. sublimation temperature 1500K Force grains to exist only there where the equilibrium temperature is below a preset sublimation temperature. I think this command is still very useful. Priority: high I hope this is somewhat clear.... I also made changes to the output, some of which may also be useful. I will discuss those at a later date. Cheers, Peter.