Calculating+Emission+Line+Ratios

First open the data file you want in the Graphical Analysis program. This will show the data a spectroscopy graph. Next find the Anaylze tab and open it and click on the Examine option, this will give you a data box on the upper right part of the graph. Then place your cursor over a point on or near the peak of one of the biggest emission lines. Note its x-value in the data box, which is the observed wavelength of the emission line.



This is what AGN spectroscopy graphs looks something like. Notice the data box on the upper left hand of the graph.

Next do the find the wavelength of the second biggest wavelength using the Examine tool and the data box. Now that you've found the wavelengths of the emission lines you find the ratio by dividing the two values you found. Simply divide the larger wavelength by the smaller one so the number is over one. After you've divided the two and found its ratio you must match it to a rest wavelength ratio on a table. Once you've found a rest wavelength ratio close to the ratio you got you have found what emission lines made up your ratio and can label the emission lines. If the ratio you found does not match one on the table then choose two new emission lines and try again.