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 \dot { P } 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 can not be excluded .
The magnitude of its rotation measure is the largest known , \mbox { RM } = -3000 rad m ^ { -2 } , and with a dispersion measure \mbox { DM } = 532 pc cm ^ { -3 } implies a large electron-weighted average magnetic field strength along the line of sight , 7 \mu G .