The University of Southampton
University of Southampton Institutional Repository

Comparing models of the periodic variations in spin-down and beamwidth for PSR B1828-11

Comparing models of the periodic variations in spin-down and beamwidth for PSR B1828-11
Comparing models of the periodic variations in spin-down and beamwidth for PSR B1828-11
We build a framework using tools from Bayesian data analysis to evaluate models explaining the periodic variations in spin-down and beamwidth of PSR B1828?11. The available data consist of the time-averaged spin-down rate, which displays a distinctive double-peaked modulation, and measurements of the beamwidth. Two concepts exist in the literature that are capable of explaining these variations; we formulate predictive models from these and quantitatively compare them. The first concept is phenomenological and stipulates that the magnetosphere undergoes periodic switching between two metastable states as first suggested by Lyne et al. The second concept, precession, was first considered as a candidate for the modulation of B1828?11 by Stairs et al. We quantitatively compare models built from these concepts using a Bayesian odds ratio. Because the phenomenological switching model itself was informed by these data in the first place, it is difficult to specify appropriate parameter-space priors that can be trusted for an unbiased model comparison. Therefore, we first perform a parameter estimation using the spin-down data, and then use the resulting posterior distributions as priors for model comparison on the beamwidth data. We find that a precession model with a simple circular Gaussian beam geometry fails to appropriately describe the data, while allowing for a more general beam geometry provides a good fit to the data. The resulting odds between the precession model (with a general beam geometry) and the switching model are estimated as 102.7±0.5 in favour of the precession model.
0035-8711
881-899
Ashton, G.
805bcbfd-ae8a-46b2-8297-f3142c3d0e7e
Jones, D. I.
b8f3e32c-d537-445a-a1e4-7436f472e160
Prix, R.
96ea3047-4071-44f4-9a9f-e9e331c61421
Ashton, G.
805bcbfd-ae8a-46b2-8297-f3142c3d0e7e
Jones, D. I.
b8f3e32c-d537-445a-a1e4-7436f472e160
Prix, R.
96ea3047-4071-44f4-9a9f-e9e331c61421

Ashton, G., Jones, D. I. and Prix, R. (2016) Comparing models of the periodic variations in spin-down and beamwidth for PSR B1828-11. Monthly Notices of the Royal Astronomical Society, 458 (1), 881-899. (doi:10.1093/mnras/stw334).

Record type: Article

Abstract

We build a framework using tools from Bayesian data analysis to evaluate models explaining the periodic variations in spin-down and beamwidth of PSR B1828?11. The available data consist of the time-averaged spin-down rate, which displays a distinctive double-peaked modulation, and measurements of the beamwidth. Two concepts exist in the literature that are capable of explaining these variations; we formulate predictive models from these and quantitatively compare them. The first concept is phenomenological and stipulates that the magnetosphere undergoes periodic switching between two metastable states as first suggested by Lyne et al. The second concept, precession, was first considered as a candidate for the modulation of B1828?11 by Stairs et al. We quantitatively compare models built from these concepts using a Bayesian odds ratio. Because the phenomenological switching model itself was informed by these data in the first place, it is difficult to specify appropriate parameter-space priors that can be trusted for an unbiased model comparison. Therefore, we first perform a parameter estimation using the spin-down data, and then use the resulting posterior distributions as priors for model comparison on the beamwidth data. We find that a precession model with a simple circular Gaussian beam geometry fails to appropriately describe the data, while allowing for a more general beam geometry provides a good fit to the data. The resulting odds between the precession model (with a general beam geometry) and the switching model are estimated as 102.7±0.5 in favour of the precession model.

Text
881.full.pdf - Version of Record
Download (9MB)

More information

Accepted/In Press date: 9 February 2016
e-pub ahead of print date: 23 February 2016
Published date: 1 May 2016
Organisations: Applied Mathematics

Identifiers

Local EPrints ID: 404310
URI: http://eprints.soton.ac.uk/id/eprint/404310
ISSN: 0035-8711
PURE UUID: fd88107a-cebb-48f4-9a93-87046c3bf5e4
ORCID for D. I. Jones: ORCID iD orcid.org/0000-0002-0117-7567

Catalogue record

Date deposited: 04 Jan 2017 15:09
Last modified: 10 Dec 2019 01:50

Export record

Altmetrics

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×