iraf.net

Hi guys,so I'm trying to model some spectra and using the interactive "d" key in splot to do it. plan is then to use the resulting FWHM and convert to a velocity. However when using a vogit you get two FWHM one for the lorentizan and on e for the guassian. So which do you use?? Also the Vogit does not appear to give the peak flux which is something else I need. Is there any way to get that???And finally I have been reading: Vhttps://iraf.net/irafhelp.php?val=splot&help=Help+Page and it states that Iraf can calculate the errors. I want to get errors for both the FWHM and peak Flux - but the link above does not appear to give any indication of how. I'm assuming there is some other window like :show i need to fine which will have all of these values in?? Does anyone know how to get there??Many thanks, Sparkles

See the help page discussion on "ERROR ESTIMATES", calculation of errors requires that you set the 'nerrsample', 'sigma0' and 'invgain' parameters to compute a suitable model. As for which FWHM value to use, there's actually an estimate you can use derived on the Wikipedia page on Voigt profiles but the final decision is up to you. Otherwise, the values you need should be in the log files.