  The identity of the persistent EGRET sources in the Galactic plane is largely
a mystery. For one of these, 3EG J2227+6122, our complete census of X-ray and
radio sources in its error circle reveals a remarkable superposition of an
incomplete radio shell with a flat radio spectrum, and a compact, power-law
X-ray source with photon index Gamma = 1.5 and with no obvious optical
counterpart. The radio shell is polarized at a level of 25%. The anomalous
properties of the radio source prevent us from deriving a completely
satisfactory theory as to its nature. Nevertheless, using data from ROSAT,
ASCA, the VLA, and optical imaging and spectroscopy, we argue that the X-ray
source may be a young pulsar with an associated wind-blown bubble or bow shock
nebula, and an example of the class of radio-quiet pulsars which are
hypothesized to comprise the majority of EGRET sources in the Galaxy. The
distance to this source can be estimated from its X-ray absorption as 3 kpc. At
this distance, the X-ray and gamma-ray luminosities would be 1.7x10^{33} and
3.7x10^{35} erg s^{-1}, respectively, which would require an energetic pulsar
to power them.
  If, on the contrary, this X-ray source is not the counterpart of 3EG
J2227+6122, then by process of elimination the X-ray luminosity of the latter
must be less than 10^{-4} of its gamma-ray luminosity, a condition not
satisfied by any established class of gamma-ray source counterpart. This would
require the existence of at least a quantitatively new type of EGRET source, as
has been suggested in studies of other EGRET fields.
