RXTE Discoveries
How Do We Know The Sources Near SMC X-3 Are Pulsars?
We can tell that the 5 outbursting sources discovered near SMC X-3 are pulsar because they have regular X-ray pulsations. The period of the sources, or frequency of pulsation are visible in the X-ray data. For example, the graph below, called a light curve, shows that the X-ray intensity varies over time. But more importantly, it varies in a consistent manner, showing dips every 59 seconds. This light curve actually belongs to the 59 second period pulsar that Drs. Lochner and Whitlock observed.
![Light curve](gifs/59secpsr.gif)
Also, BeppoSAX had observed this area of the sky fairly recently, allowing confirmation of their identities.