Death Line of Gamma-ray Pulsars with Outer Gaps
Figure 2 of "Death Line of Gamma-ray Pulsars with Outer Gaps", Ren-Bo Wang and Kouichi Hirotani, ApJ 736, 127 (2011).
By the advent of Fermi space observatory, the number of rotation-powered, gamma-ray pulsars has been increased from seven to more than one hundred. Thus, it is desired to derive a theoretical condition for a pulsar to become a gamma-ray emitter in a wide pulsar parameter space. On these grounds, we derived the death line (red, solid line) of high-energy pulsars on the period versus period-derivative plane, by analyzing the condition for an outer-magnetospheric accelerator to be maintained by photon-photon pair productions. The thin dotted lines express the parameter region that gives the labeled magnetic-field strength at the light cylinder. The (blue) large points denote the gamma-ray detected pulsars, whereas the (green) small open circles the X-ray detected ones. The entire parameter space is depicted in the left panel, while a close up of millisecond parameter range is depicted in the right panel. This theoretical prediction (red line) is being testified by various X-ray and gamma-ray observations.