A NICER thermonuclear burst from the millisecond X-Ray pulsar SAX J1808.4-3658
A NICER thermonuclear burst from the millisecond X-Ray pulsar SAX J1808.4-3658
The Neutron Star Interior Composition Explorer (NICER) has extensively monitored the 2019 August outburst of the 401 Hz millisecond X-ray pulsar SAX J1808.4–3658. In this Letter, we report on the detection of a bright helium-fueled Type I X-ray burst. With a bolometric peak flux of (2.3 ± 0.1) × 10−7 erg s−1 cm−2, this was the brightest X-ray burst among all bursting sources observed with NICER to date. The burst shows a remarkable two-stage evolution in flux, emission lines at 1.0 and 6.7 keV, and burst oscillations at the known pulsar spin frequency, with ≈4% fractional sinusoidal amplitude. We interpret the burst flux evolution as the detection of the local Eddington limits associated with the hydrogen and helium layers of the neutron star envelope. The emission lines are likely associated with Fe, due to reprocessing of the burst emission in the accretion disk.
Bult, Peter
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Jaisawal, Gaurava K.
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Guver, Tolga
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Strohmayer, Tod E.
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Altamirano, Diego
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Arzoumanian, Zaven
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Ballantyne, David R.
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Chakrabarty, Deepto
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Chenevez, Jérôme
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Gendreau, Keith C.
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Guillot, Sebastien
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Ludlam, Renee M.
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Bult, Peter
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Jaisawal, Gaurava K.
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Guver, Tolga
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Strohmayer, Tod E.
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Altamirano, Diego
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Arzoumanian, Zaven
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Ballantyne, David R.
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Chakrabarty, Deepto
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Chenevez, Jérôme
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Gendreau, Keith C.
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Guillot, Sebastien
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Ludlam, Renee M.
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Bult, Peter, Jaisawal, Gaurava K., Guver, Tolga, Strohmayer, Tod E., Altamirano, Diego, Arzoumanian, Zaven, Ballantyne, David R., Chakrabarty, Deepto, Chenevez, Jérôme, Gendreau, Keith C., Guillot, Sebastien and Ludlam, Renee M.
(2019)
A NICER thermonuclear burst from the millisecond X-Ray pulsar SAX J1808.4-3658.
The Astrophysical Journal Letters, 855 (1), [L1].
(doi:10.3847/2041-8213/ab4ae1).
Abstract
The Neutron Star Interior Composition Explorer (NICER) has extensively monitored the 2019 August outburst of the 401 Hz millisecond X-ray pulsar SAX J1808.4–3658. In this Letter, we report on the detection of a bright helium-fueled Type I X-ray burst. With a bolometric peak flux of (2.3 ± 0.1) × 10−7 erg s−1 cm−2, this was the brightest X-ray burst among all bursting sources observed with NICER to date. The burst shows a remarkable two-stage evolution in flux, emission lines at 1.0 and 6.7 keV, and burst oscillations at the known pulsar spin frequency, with ≈4% fractional sinusoidal amplitude. We interpret the burst flux evolution as the detection of the local Eddington limits associated with the hydrogen and helium layers of the neutron star envelope. The emission lines are likely associated with Fe, due to reprocessing of the burst emission in the accretion disk.
Text
A NICER Thermonuclear Burst from the Millisecond X-Ray Pulsar SAX J1808.4-3658
- Accepted Manuscript
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Accepted/In Press date: 4 October 2019
e-pub ahead of print date: 23 October 2019
Additional Information:
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Identifiers
Local EPrints ID: 437002
URI: http://eprints.soton.ac.uk/id/eprint/437002
ISSN: 2041-8205
PURE UUID: 46e23720-e7b4-423f-9567-be21136d8120
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Date deposited: 15 Jan 2020 17:30
Last modified: 12 Nov 2024 02:49
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Contributors
Author:
Peter Bult
Author:
Gaurava K. Jaisawal
Author:
Tolga Guver
Author:
Tod E. Strohmayer
Author:
Zaven Arzoumanian
Author:
David R. Ballantyne
Author:
Deepto Chakrabarty
Author:
Jérôme Chenevez
Author:
Keith C. Gendreau
Author:
Sebastien Guillot
Author:
Renee M. Ludlam
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