iraf.net

Hi guys,
I'm trying to use splot to model some double peaked spectra. there is really not much info on this stuff. I've tried using the d key to set the continuum level and fit a Lorentzian function to one of the two peaks. Is there any way of telling Iraf to miss out the region over which the second peak sits as it keeps trying to take it into account as part of the continuum??? Also how far out should go when setting the continuum with d. It really seems to change my equivalent width value quite a lot!! so my values seem very unreliable?and is there anyway to get Iraf to measure the number of counts within the function so that I can calculate the error of these values?? If not I'll use ds9. Many thanks again guys

The 'd' key is intended to fit multiple lines, so even if you don't want the results from the second line you should still use it in the fit since it is a part of the shape in the first line being fitted. Marking the continuum points is a bit of a black art and depends in part on whether/how-well the continuum has already been fit. When doing the deblend one of the options asked is whether you want to fit the background, answering 'no' will cause the fit to be done using the points you select and not float to unreasonable levels because of the line fit.