PSR J1841-0500: a radio pulsar that mostly is not there
  In a search for radio pulsations from the magnetar 1E 1841-045, we have
discovered the unrelated pulsar J1841-0500, with rotation period P=0.9 s and
characteristic age 0.4 Myr. One year after discovery with the Parkes telescope
at 3 GHz, radio emission ceased from this bright pulsar. After 580 days,
emission resumed as before. The P-dot during both on states is 250% of the
average in the off state. PSR J1841-0500 is a second example of an extremely
intermittent pulsar, although with a much longer off period and larger ratio of
spin-down rates than PSR B1931+24. The new pulsar is hugely scattered by the
ISM, with a fitted timescale referenced to 1 GHz of tau_1=2 s. Based on
polarimetric observations at 5 GHz with the Green Bank Telescope, the intrinsic
pulse profile has not obviously changed between the two on states observed so
far, although relatively small variations cannot be excluded. The magnitude of
its rotation measure is the largest known, RM=-3000 rad/m^2, and with a
dispersion measure DM=532 pc/cc implies a large electron-weighted average
magnetic field strength along the line of sight, 7 microG.
