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# The enigmatic spin evolution of PSR J0537-6910: r-modes, gravitational waves and the case for continued timing

Andersson, N., Antonopoulou, D., Espinoza, C.M., Haskell, B. and Ho, W.C.G. (2018) The enigmatic spin evolution of PSR J0537-6910: r-modes, gravitational waves and the case for continued timing. The Astrophysical Journal, 864 (2), 1-8, [137-[8pp]].

Record type: Article

## Abstract

We discuss the unique spin evolution of the young X-ray pulsar PSR J0537-6910, a system in which the regular spin down is interrupted by glitches every few months. Drawing on the complete timing data from the Rossi X-ray Timing Explorer (RXTE, from 1999-2011), we argue that a trend in the inter-glitch behaviour points to an effective braking index close to $n=7$, much larger than expected. This value is interesting because it would accord with the neutron star spinning down due to gravitational waves from an unstable r-mode. We discuss to what extent this, admittedly speculative, scenario may be consistent and if the associated gravitational-wave signal would be within reach of ground based detectors. Our estimates suggest that one may, indeed, be able to use future observations to test the idea. Further precision timing would help enhance the achievable sensitivity and we advocate a joint observing campaign between the Neutron Star Interior Composition ExploreR (NICER) and the LIGO-Virgo network.

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rmode0537_apj - Author's Original
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Andersson 2018 ApJ 864 137 - Version of Record

Accepted/In Press date: 28 July 2018
e-pub ahead of print date: 10 September 2018

## Identifiers

Local EPrints ID: 416266
URI: http://eprints.soton.ac.uk/id/eprint/416266
ISSN: 1538-4357
PURE UUID: 0d773d27-1695-4139-bb58-83d9e9da5ce3
ORCID for W.C.G. Ho: orcid.org/0000-0002-6089-6836

## Catalogue record

Date deposited: 11 Dec 2017 17:30

## Contributors

Author: D. Antonopoulou
Author: C.M. Espinoza
Author: W.C.G. Ho