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Anticorrelation between X-ray luminosity and pulsed fraction in the Small Magellanic Cloud pulsar SXP 1323

Anticorrelation between X-ray luminosity and pulsed fraction in the Small Magellanic Cloud pulsar SXP 1323
Anticorrelation between X-ray luminosity and pulsed fraction in the Small Magellanic Cloud pulsar SXP 1323

We report the evidence for the anticorrelation between pulsed fraction (PF) and luminosity of the X-ray pulsar SXP 1323, found for the first time in a luminosity range 1035-1037 erg s-1 from observations spanning 15 yr. The phenomenon of a decrease in X-ray PF when the source flux increases has been observed in our pipeline analysis of other X-ray pulsars in the Small Magellanic Cloud. It is expected that the luminosity under a certain value decreases as the PF decreases due to the propeller effect. Above the propeller region, an anticorrelation between the PF and the flux might occur either as a result of an increase in the unpulsed component of the total emission or a decrease of the pulsed component. Additional modes of accretion may also be possible, such as spherical accretion and a change in emission geometry. At higher mass accretion rates, the accretion disc could also extend closer to the neutron star surface, where a reduced inner radius leads to hotter inner disc emission. These modes of plasma accretion may affect the change in the beam configuration to fan-beam dominant emission.

Pulsars: individual: SXP 1323, X-rays: binaries
1745-3925
L1-L6
Yang, Jun
47673b30-c7b5-4342-a34f-9f506c1804a3
Zezas, Andreas
b09e794a-5973-4f3d-bdb1-6a709e560df8
Coe, Malcolm J.
04dfb23b-1456-46a3-9242-5cee983471d5
Drake, Jeremy J.
8c6fab1e-a517-4a97-ad90-904e79cda61a
Hong, Jae Sub
12e1ec71-e93d-4c74-b7cd-cb27848cf094
Laycock, Silas G.T.
d4e5bb78-7038-4e42-aaf5-9fdc20f60037
Wik, Daniel R.
f4f10fac-a438-44be-8cdf-ebe76ce0c7be
Yang, Jun
47673b30-c7b5-4342-a34f-9f506c1804a3
Zezas, Andreas
b09e794a-5973-4f3d-bdb1-6a709e560df8
Coe, Malcolm J.
04dfb23b-1456-46a3-9242-5cee983471d5
Drake, Jeremy J.
8c6fab1e-a517-4a97-ad90-904e79cda61a
Hong, Jae Sub
12e1ec71-e93d-4c74-b7cd-cb27848cf094
Laycock, Silas G.T.
d4e5bb78-7038-4e42-aaf5-9fdc20f60037
Wik, Daniel R.
f4f10fac-a438-44be-8cdf-ebe76ce0c7be

Yang, Jun, Zezas, Andreas, Coe, Malcolm J., Drake, Jeremy J., Hong, Jae Sub, Laycock, Silas G.T. and Wik, Daniel R. (2018) Anticorrelation between X-ray luminosity and pulsed fraction in the Small Magellanic Cloud pulsar SXP 1323. Monthly Notices of the Royal Astronomical Society: Letters, 479 (1), L1-L6. (doi:10.1093/mnrasl/sly085).

Record type: Article

Abstract

We report the evidence for the anticorrelation between pulsed fraction (PF) and luminosity of the X-ray pulsar SXP 1323, found for the first time in a luminosity range 1035-1037 erg s-1 from observations spanning 15 yr. The phenomenon of a decrease in X-ray PF when the source flux increases has been observed in our pipeline analysis of other X-ray pulsars in the Small Magellanic Cloud. It is expected that the luminosity under a certain value decreases as the PF decreases due to the propeller effect. Above the propeller region, an anticorrelation between the PF and the flux might occur either as a result of an increase in the unpulsed component of the total emission or a decrease of the pulsed component. Additional modes of accretion may also be possible, such as spherical accretion and a change in emission geometry. At higher mass accretion rates, the accretion disc could also extend closer to the neutron star surface, where a reduced inner radius leads to hotter inner disc emission. These modes of plasma accretion may affect the change in the beam configuration to fan-beam dominant emission.

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Anticorrelation between X-ray luminosity and pulsed fraction in the Small Magellanic Cloud pulsar SXP 1323 - Accepted Manuscript
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Accepted/In Press date: 8 May 2018
e-pub ahead of print date: 14 May 2018
Published date: September 2018
Keywords: Pulsars: individual: SXP 1323, X-rays: binaries

Identifiers

Local EPrints ID: 425638
URI: http://eprints.soton.ac.uk/id/eprint/425638
ISSN: 1745-3925
PURE UUID: c7f4b787-ed8a-4798-8ec5-6ff36632454e
ORCID for Malcolm J. Coe: ORCID iD orcid.org/0000-0002-0763-8547

Catalogue record

Date deposited: 30 Oct 2018 17:30
Last modified: 16 Mar 2024 02:35

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Contributors

Author: Jun Yang
Author: Andreas Zezas
Author: Malcolm J. Coe ORCID iD
Author: Jeremy J. Drake
Author: Jae Sub Hong
Author: Silas G.T. Laycock
Author: Daniel R. Wik

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