PSR J1841-0500: a radio pulsar that mostly is not there

TL;DR

This paper reports the discovery of an extremely intermittent radio pulsar, J1841-0500, which exhibits long off periods, significant changes in spin-down rate, and extreme interstellar scattering, revealing new insights into pulsar emission variability.

Contribution

The study presents the first detailed observation of a pulsar with long off periods and large spin-down rate variations, expanding understanding of pulsar intermittency and ISM effects.

Findings

Pulsar J1841-0500 has a 0.9 s period and exhibits long off-on cycles.

The pulsar's spin-down rate varies significantly between on and off states.

It has the largest known rotation measure, indicating a strong magnetic field along the line of sight.

Abstract

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.