  We report the discovery of PSR J1838-0537, a gamma-ray pulsar found through a
blind search of data from the Fermi Large Area Telescope (LAT). The pulsar has
a spin frequency of 6.9 Hz and a frequency derivative of -2.2e-11 Hz/s,
implying a young characteristic age of 4970 years and a large spin-down power
of 5.9e36 erg/s. Follow-up observations with radio telescopes detected no
pulsations, thus PSR J1838-0537 appears radio-quiet as viewed from Earth. In
September 2009 the pulsar suffered the largest glitch so far seen in any
gamma-ray-only pulsar, causing a relative increase in spin frequency of about
5.5e-6. After the glitch, during a putative recovery period, the timing
analysis is complicated by the sparsity of the LAT photon data, the weakness of
the pulsations, and the reduction in average exposure from a coincidental,
contemporaneous change in the LAT's sky-survey observing pattern. The pulsar's
sky position is coincident with the spatially extended TeV source HESS
J1841-055 detected by the High Energy Stereoscopic System (H.E.S.S.). The
inferred energetics suggest that HESS J1841-055 contains a pulsar wind nebula
powered by the pulsar.
