The Detection and Investigations of Strong Pulses from PSR B1237+25

Strong pulse is a special kind of single pulse that manifests as strong radio bursts. We present the strong pulse emission properties from PSR B1237+25 at 1540 MHz using the Nanshan 25 m radio telescope. Their peak flux densities range from 10.2 to 82.5 times that of the average pulse profile. We perform fit for the statistical distributions for the peak flux density ratio, S/N (signal-to-noise ratio), and W 50 (full width of half maximum, FWHM) with lognormal curves. We first discover a weak innermost cone around the core at 1540 MHz. The new discovered cone belongs to the partial cone categories, and its leading edge is too weak to detect. Our analysis of the structures of the three cones shows that the new innermost cone is located close to the core component, and the emission height increases from innermost to outermost cones at a step of 300 km.