A Comprehensive Study of the X‐Ray Bursts from the Magnetar Candidate 1E 2259+586

We present a statistical analysis of the X-ray bursts observed from the 2002June 18 outburst of the Anomalous X-ray Pulsar (AXP) 1E 2259+586, observed withthe Proportional Counter Array (PCA) aboard the Rossi X-ray Timing Explorer. Weshow that the properties of these bursts are similar to those of SoftGamma-Repeaters (SGRs). The similarities we find are the burst durations followa log-normal distribution which peaks at 99 ms, the differential burst fluencedistribution is well described by a power law of index -1.7, the burst fluencesare positively correlated with the burst durations, the distribution of waitingtimes is well described by a log-normal distribution of mean 47 s, and thebursts are generally asymmetric with faster rise than fall times. However, wefind several quantitative differences between the AXP and SGR bursts.Specifically, the AXP bursts we observed exhibit a wider range of durations,the correlation between burst fluence and duration is flatter than for SGRs,the observed AXP bursts are on average less energetic than observed SGR bursts,and the more energetic AXP bursts have the hardest spectra -- the opposite ofwhat is seen for SGRs. We conclude that the bursts are sufficiently similarthat AXPs and SGRs can be considered united as a source class yet there aresome interesting differences that may help determine what physicallydifferentiates the two closely related manifestations of neutron stars.Comment: 32 pages, 12 figures, submitted to Ap