We report the detection of radio and X-ray pulsations at a period of 51.6 ms from the X-ray source RX/AX J2229.0+6114 in the error box of the EGRET source 3EG J2227+6122 .
An ephemeris derived from a single ASCA observation and multiple epochs at 1412 MHz from Jodrell Bank indicates steady spin-down with \dot { P } = 7.83 \times 10 ^ { -14 } s s ^ { -1 } .
From the measured P and \dot { P } we derive spin-down power \dot { E } = 2.2 \times 10 ^ { 37 } ergs s ^ { -1 } , magnetic field B _ { p } = 2.0 \times 10 ^ { 12 } G , and characteristic age P / 2 \dot { P } = 10 , 460 yr. An image from the Chandra X-ray Observatory reveals a point source surrounded by centrally peaked diffuse emission that is contained within an incomplete radio shell .
We assign the name G106.6+2.9 to this new supernova remnant , which is evidently a pulsar wind nebula .
For a distance of 3 kpc estimated from X-ray absorption , the ratio of X-ray luminosity to spin-down power is \approx 8 \times 10 ^ { -5 } , smaller than that of most pulsars , but similar to the Vela pulsar .
If PSR J2229+6114 is the counterpart of 3EG J2227+6122 then its efficiency of gamma-ray production , if isotropic , is 0.016 ( d / 3 { kpc } ) ^ { 2 } .
It obeys an established trend of \gamma -ray efficiency among known \gamma -ray pulsars which , in combination with the demonstrated absence of any other plausible counterpart for 3EG J2227+6122 , makes the identification compelling .
If confirmed , this identification bolsters the pulsar model for unidentified Galactic EGRET sources .