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arXiv · 1705.10005

The braking index of millisecond magnetars

Paul D. Lasky·Cristiano Leris·Antonia Rowlinson·Kostas Glampedakis
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Abstract

We make the first measurement of the braking index $n$ of two putative millisecond magnetars born in short gamma-ray bursts. We measure $n=2.9\pm0.1$ and $n=2.6\pm0.1$ for millisecond magnetars born in GRB 130603B and GRB 140903A respectively. The neutron star born in GRB 130603B has the only known braking index consistent with the fiducial $n=3$ value. This value is ruled out with 99.95\% confidence for GRB 140903A. We discuss possible causes of $n<3$ braking indices in millisecond magnetars, showing that several models can account for the measurement of the braking index in GRB 140903A, while it is more difficult to account for a braking index consistent with $n=3$.

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Paul D. Lasky, Cristiano Leris, Antonia Rowlinson, Kostas Glampedakis. 2017-05-29. The braking index of millisecond magnetars. https://doi.org/10.3847/2041-8213%2Faa79a7

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