Now we will select one data interval for which to analyze the spectra. More can be selected but for this demonstration, we are just interested in the spectrum of the interval with the highest flux. Each interval that you select should of course be exclusive of your background periods. Type on the command line:

SPEX> select_interval

and the following window should appear:

Click on the "Graphic Input" button.

Then the "INTERVAL SELECTION" window will appear as follows:

Click on the "AS BOUNDARIES FOR DISCRETE INTERVALS" button.

The selection of data analysis intervals is then the same as for selecting the background intervals. The same CURSOR CONTROLS window that used during background selection appears. Click on the "Continue by Selecting from Plot Window" button as was done for the background selection. Because we selected "discrete intervals", the first mouse click defines the start of an interval and the second defines the end. Again, remember to choose the interval "inside" the actual 1-minute data intervals to avoid selecting an interval wider than intended. I will do just 2 clicks to make a single interval and the figure will look like this, where you can see the time interval I have selected -

Next, move the mouse back out of the window and click on the "DONE" button in the CURSOR CONTROLS window.

Regraph by typing "graph" and then type "display" to show the selected time interval in theTime History Window -

Now SPEX has a background model, an instrument response, and a single time interval in which to accumulate spectra.

This page last updated: June 27, 2011