2004ApJ...612..389H

We present the results from X-ray and radio observations of the recently discovered young Vela-like pulsar PSR J2021+3651, which is coincident with the EGRET γ-ray source GeV 2020+3658. A 19.0 ks Chandra ACIS-S observation has revealed a ∼20''x10'' pulsar wind nebula that is reminiscent of the equatorial tori seen around some young pulsars, along with thermal emission from an embedded point source (kT_∞=0.15±0.02 keV). We have named the nebula G75.2+0.1. Its spectrum is well fitted by an absorbed power-law model with a photon index of Γ=1.7^+0.3_–0.2, a hydrogen column density of N_H=(7.8^+1.7_–1.4)x10²¹/cm2, and an unabsorbed 0.5-10.0 keV flux of (1.7±0.1)x10^–12 ergs/cm2/s. We have spatially fitted G75.2+0.1 with a model that assumes a toroidal morphology, and from this we infer that the axis of the torus is highly inclined to the line of sight. A 20.8 ks Chandra observation in continuous-clocking mode reveals a possible pulse detection, with a pulsed fraction of ∼65% and an H-test probability of occurring by chance of 8.9x10^–5. Timing observations with the Arecibo radio telescope spanning 2 yr show that PSR J2021+3651 glitched sometime between MJD 52,616 and 52,645 with parameters Δν/ν=(2.587±0.002)x10^–6 and Δν{dot}/ν{dot}=(6.2±0.3)x10^–3, similar to those of the largest glitches observed in the Vela pulsar. PSR J2021+3651 is heavily scattered (τ_sc=17.7±0.9 ms at 1 GHz) and exhibits a significant amount of timing noise.