Create and Display a Light Curve

To create a light curve by using the heraXmmselect GUI:

1)

Check the diamond to the left of the ``Time'' entry.

2)

Click on the ``OGIP Rate Curve'' button near the bottom of the page. This brings up the evselect GUI (see Figure 7.1).

3)

Click on the ``Lightcurve'' tab and change the ``timebinsize'' to a reasonable amount, e.g. 10 or 100 s. Change the name of the output file in the ``rateset'' box to, say, mos1_ltcrv.fits.

4)

Click on the ``Run'' button at the lower left corner of the evselect GUI.

The resultant light curve is written to the file mos1_ltcrv.fits and is automatically displayed in POW; see Fig. 7.3.

To create a light curve by using the Command Window, type:

evselect table=mos1.fits withrateset=yes rateset=mos1_ltcrv.fits
$$ maketimecolumn=yes timecolumn=TIME timebinsize=100 makeratecolumn=yes

where

table - input event table
withrateset - make a light curve
rateset - name of output light curve file
maketimecolumn - control to create a time column
timecolumn - time column label
timebinsize - time binning (seconds)
makeratecolumn - control to create a count rate column, otherwise a count column will be created

The output file mos1_ltcrv.fits can be viewed with POW; see Fig. 7.3.

Figure 7.3: The light curve.