added info about plots

index.html

@@ -37,6 +37,13 @@ in our Universe.</p>
 each pulsar we list the volunteers whose computers discovered the pulsar, and the date at
 which the pulsar was found.</p>
 
+<p>The plots on the right show the pulse profile of each pulsar in green, and the phase-folded
+arrival times of all the gamma-ray photons on the far right. These plots require precise
+knowledge of the pulsar sky position, its spin frequency, and spin frequency derivative.
+Using these, each photon can be assigned a rotational phase, i.e., in which direction the
+pulsar was pointing when the gamma-ray photon was emitted. Thus, we can reconstruct the
+gamma-ray emission as a function of pulsar rotation phase and resolve the pulse profile.</p>
+
 <p>We also provide a list of selected characteristics for each
 of the pulsars. Right ascension is one of the two celestial coordinates that specify the
 sky position of the pulsar. Declination is the second of these. The spin frequency describes