RADIO DETECTION OF LAT PSRs J1741-2054 AND J2032+4127: NO LONGER JUST GAMMA-RAY PULSARS

Abstract

Sixteen pulsars have been discovered so far in blind searches of photons\ncollected with the Large Area Telescope on the Fermi Gamma-ray Space Telescope.\nWe here report the discovery of radio pulsations from two of them. PSR\nJ1741-2054, with period P=413ms, was detected in archival Parkes telescope data\nand subsequently has been detected at the Green Bank Telescope (GBT). Its\nreceived flux varies greatly due to interstellar scintillation and it has a\nvery small dispersion measure of DM=4.7pc/cc, implying a distance of ~0.4kpc\nand possibly the smallest luminosity of any known radio pulsar. At this\ndistance, for isotropic emission, its gamma-ray luminosity above 0.1GeV\ncorresponds to 25% of the spin-down luminosity of dE/dt=9.4e33erg/s. The\ngamma-ray profile occupies 1/3 of pulse phase and has three closely-spaced\npeaks with the first peak lagging the radio pulse by delta=0.29P. We have also\nidentified a soft Swift source that is the likely X-ray counterpart. In many\nrespects PSR J1741-2054 resembles the Geminga pulsar. The second source, PSR\nJ2032+4127, was detected at the GBT. It has P=143ms, and its DM=115pc/cc\nsuggests a distance of ~3.6kpc, but we consider it likely that it is located\nwithin the Cyg OB2 stellar association at half that distance. The radio\nemission is nearly 100% linearly polarized, and the main radio peak precedes by\ndelta=0.15P the first of two narrow gamma-ray peaks that are separated by\nDelta=0.50P. Faint, diffuse X-ray emission in a Chandra image is possibly its\npulsar wind nebula. PSR J2032+4127 likely accounts for the EGRET source 3EG\nJ2033+4118, while its pulsar wind is responsible for the formerly unidentified\nHEGRA source TeV J2032+4130.\n