On The braking index of the unusual high-B rotation-powered pulsar PSR J1846-0258 [HEAP]

http://arxiv.org/abs/1506.06104


PSR J1846-0258 is an object which straddles the boundary between magnetars and rotation powered pulsars. Though behaving for many years as a rotation-powered pulsar, in 2006, it exhibited distinctly magnetar-like behavior – emitting several short hard X-ray bursts, and a flux increase. Here we report on 7 years of post-outburst timing observations of PSR J1846-0258 using the Rossi X-ray Timing Explorer and the Swift X-ray Telescope. We measure the braking index over the post-magnetar outburst period to be $n=2.19\pm0.03$. This represents a change of $\Delta n=-0.46\pm0.03$ or a 14.5$\;\sigma$ difference from the pre-outburst braking index of $n=2.65\pm0.01$, which itself was measured over a span of 6.5 yr (Livingstone et al. 2006). So large and long-lived a change to a pulsar braking index is unprecedented and poses a significant challenge to models of pulsar spin-down.

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R. Archibald, V. Kaspi, A. Beardmore, et. al.
Mon, 22 Jun 15
26/41

Comments: 7 pages, 5 figures. Submitted to APJ