Anomalous X-ray Pulsar 1E 1048.1-5937: Pulsed Flux Flares and Large Torque Variations

Abstract

We report on continued monitoring of the Anomalous X-ray pulsar (AXP) 1E 1048.1-5937 using the Rossi X-ray Timing Explorer. We confirm that this pulsar has exhibited significant pulsed flux variability. The principal features of this variability are two pulsed X-ray flares. Both flares lasted several months and had well-resolved few-week-long rises. The long rise times of the flares are a phenomenon not previously reported for this class of object. The epochs of the flare peaks were MJD 52,218.8+/-4.5 and 52,444.4+/-7.0. Both flares had shorter rise than fall times. The flares had peak fluxes of 2.21+/-0.16 and 3.00+/-0.13 times the quiescent value. We estimate a total 2-10 keV energy release of ~2.7x10^40 ergs and ~2.8x10^41 ergs for the flares, assuming a distance of 5 kpc. We also report large (factor of ~12) changes to the pulsar's spin-down rate on time scales of weeks to months, shorter than has been reported previously. We find marginal evidence for correlation between the flux and spin-down rate variability, with probability of nonrandom correlation 6%. We discuss the implications of our findings for AXP models.

11 pages, 2 figures, ApJ Letters accepted. Modifications to the text, calculations and figures. We corrected a problem which resulted in reducing the scatter in the earlier flux points in Figure 1. Conclusions unchanged

References in corpus (7)

• A Major SGR-like Outburst and Rotation Glitch in the No-Longer-So-Anomalous X-ray Pulsar 1E 2259+586
• Magnetar-like X-ray Bursts from an Anomalous X-ray Pulsar
• Changes in the X-ray Emission from the Magnetar Candidate 1E 2259+586 during its 2002 Outburst
• A Comprehensive Study of the X-ray Bursts from the Magnetar Candidate 1E 2259+586
• Diagnosing magnetars with transient cooling
• The detection of variability from the candidate IR counterpart to the Anomalous X-ray Pulsar 1E1048.1-5937
• The Likely Near-Infrared Counterpart to the Anomalous X-Ray Pulsar 1E 1048.1-5937

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