Discovery of Radio Pulsations from the X-Ray Pulsar J0205+6449 in Supernova Remnant 3C 58 with the Green Bank Telescope

Abstract

We report the discovery with the 100 m Green Bank Telescope of 65 ms radio pulsations from the X-ray pulsar J0205+6449 at the center of supernova remnant 3C 58, making this possibly the youngest radio pulsar known. From our observations at frequencies of 820 and 1375 MHz, the free-electron column density to PSR J0205+6449 is found to be 140.7 ± 0.3 cm^-3 pc. The barycentric pulsar period P and period derivative determined from a phase-coherent timing solution are consistent with the values previously measured from X-ray observations. The averaged radio profile of PSR J0205+6449 consists of one sharp pulse of width ≈3 ms ≈ 0.05P. The pulsar is an exceedingly weak radio source, with a pulse-averaged flux density in the 1400 MHz band of ~45 μJy and a spectral index of ~-2.1. Its radio luminosity of ~0.5 mJy kpc² at 1400 MHz is lower than that of ~99% of known pulsars and is the lowest among known young pulsars.