A Phase-connected Timing Solution for the Magnetar Candidate 1E 1841−045

Abstract

We report on a long-term monitoring campaign of 1E 1841-045, the 12 s anomalous X-ray pulsar and magnetar candidate at the center of the supernova remnant Kes 73. We have obtained approximately monthly observations of the pulsar with the Rossi X-Ray Timing Explorer (RXTE) spanning over 2 years, during which time 1E 1841-045 is found to be rotating with sufficient stability to derive a phase-connected solution. A linear ephemeris is consistent with measurements of the pulse period made over the last 15 years with the Ginga, ASCA, RXTE, and BeppoSAX observatories. Phase residuals suggest the presence of timing noise, as is typically observed from young radio pulsars. These results confirm a rapid, constant spin-down for the pulsar, which continues to maintain a steady flux; this is inconsistent with most accretion scenarios.