 Double pulsar system (Artist's impression) Credit: John Rowe Animations/ATNF-CSIRO Filename = PulsarsCurrentHuge0139.jpg Thumbnail: PulsarsCurrent0139.jpg |  Period-Period Derivative plot for all known pulsars Credit: ATNF Pulsar Catalogue Filename = ppdot.png |  Gravitational-wave strain versus frequency for astrophysical sources and some detectors Credit: PPTA Collaboration Filename = GW_spectrum_hsens.png |