The NuSTAR view of the non-thermal emission from PSR J0437-4715

S. Guillot, V M Kaspi, Robert F. Archibald, M. Bachetti, J.C. Flynn, F. Jankowski, M. Bailes, S. Boggs, Finn Erland Christensen, W. W. Craig, Charles A. Hailey, F. A. Harrison, D. Stern, W. W. Zhang

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Abstract

We present a hard X-ray Nuclear Spectroscopic Telescope Array (NuSTAR) observation of PSR J0437-4715, the nearest millisecond pulsar. The known pulsations at the apparent pulse period similar to 5.76 ms are observed with a significance of 3.7 sigma, at energies up to 20 keV above which the NuSTAR background dominates. We measure a photon index Gamma = 1.50 +/- 0.25 (90 per cent confidence) for the power-law fit to the non-thermal emission. It had been shown that spectral models with two or three thermal components fit the XMM-Newton spectrum of PSR J0437-4715, depending on the slope of the power-law component, and the amount of absorption of soft X-rays. The new constraint on the high-energy emission provided by NuSTAR removes ambiguities regarding the thermal components of the emission below 3 keV. We performed a simultaneous spectral analysis of the XMM-Newton and NuSTAR data to confirm that three thermal components and a power law are required to fit the 0.3-20 keV emission of PSR J0437-4715. Adding a ROSAT-PSPC spectrum further confirmed this result and allowed us to better constrain the temperatures of the three thermal components. A phase-resolved analysis of the NuSTAR data revealed no significant change in the photon index of the high-energy emission. This NuSTAR observation provides further impetus for future observations with the NICER mission (Neutron Star Interior Composition Explorer) whose sensitivity will provide much stricter constraints on the equation of state of nuclear matter by combining model fits to the pulsar's phase-folded light curve with the pulsar's well-defined mass and distance from radio timing observations.
Original languageEnglish
JournalMonthly Notices of the Royal Astronomical Society
Volume463
Issue number3
Pages (from-to)2612-2622
ISSN0035-8711
DOIs
Publication statusPublished - 2016

Bibliographical note

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. ©:2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

Cite this

Guillot, S., Kaspi, V. M., Archibald, R. F., Bachetti, M., Flynn, J. C., Jankowski, F., ... Zhang, W. W. (2016). The NuSTAR view of the non-thermal emission from PSR J0437-4715. Monthly Notices of the Royal Astronomical Society, 463(3), 2612-2622. https://doi.org/10.1093/mnras/stw2194
Guillot, S. ; Kaspi, V M ; Archibald, Robert F. ; Bachetti, M. ; Flynn, J.C. ; Jankowski, F. ; Bailes, M. ; Boggs, S. ; Christensen, Finn Erland ; Craig, W. W. ; Hailey, Charles A. ; Harrison, F. A. ; Stern, D. ; Zhang, W. W. / The NuSTAR view of the non-thermal emission from PSR J0437-4715. In: Monthly Notices of the Royal Astronomical Society. 2016 ; Vol. 463, No. 3. pp. 2612-2622.
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abstract = "We present a hard X-ray Nuclear Spectroscopic Telescope Array (NuSTAR) observation of PSR J0437-4715, the nearest millisecond pulsar. The known pulsations at the apparent pulse period similar to 5.76 ms are observed with a significance of 3.7 sigma, at energies up to 20 keV above which the NuSTAR background dominates. We measure a photon index Gamma = 1.50 +/- 0.25 (90 per cent confidence) for the power-law fit to the non-thermal emission. It had been shown that spectral models with two or three thermal components fit the XMM-Newton spectrum of PSR J0437-4715, depending on the slope of the power-law component, and the amount of absorption of soft X-rays. The new constraint on the high-energy emission provided by NuSTAR removes ambiguities regarding the thermal components of the emission below 3 keV. We performed a simultaneous spectral analysis of the XMM-Newton and NuSTAR data to confirm that three thermal components and a power law are required to fit the 0.3-20 keV emission of PSR J0437-4715. Adding a ROSAT-PSPC spectrum further confirmed this result and allowed us to better constrain the temperatures of the three thermal components. A phase-resolved analysis of the NuSTAR data revealed no significant change in the photon index of the high-energy emission. This NuSTAR observation provides further impetus for future observations with the NICER mission (Neutron Star Interior Composition Explorer) whose sensitivity will provide much stricter constraints on the equation of state of nuclear matter by combining model fits to the pulsar's phase-folded light curve with the pulsar's well-defined mass and distance from radio timing observations.",
author = "S. Guillot and Kaspi, {V M} and Archibald, {Robert F.} and M. Bachetti and J.C. Flynn and F. Jankowski and M. Bailes and S. Boggs and Christensen, {Finn Erland} and Craig, {W. W.} and Hailey, {Charles A.} and Harrison, {F. A.} and D. Stern and Zhang, {W. W.}",
note = "This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. {\circledC}:2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.",
year = "2016",
doi = "10.1093/mnras/stw2194",
language = "English",
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Guillot, S, Kaspi, VM, Archibald, RF, Bachetti, M, Flynn, JC, Jankowski, F, Bailes, M, Boggs, S, Christensen, FE, Craig, WW, Hailey, CA, Harrison, FA, Stern, D & Zhang, WW 2016, 'The NuSTAR view of the non-thermal emission from PSR J0437-4715', Monthly Notices of the Royal Astronomical Society, vol. 463, no. 3, pp. 2612-2622. https://doi.org/10.1093/mnras/stw2194

The NuSTAR view of the non-thermal emission from PSR J0437-4715. / Guillot, S.; Kaspi, V M; Archibald, Robert F.; Bachetti, M.; Flynn, J.C.; Jankowski, F.; Bailes, M.; Boggs, S.; Christensen, Finn Erland; Craig, W. W.; Hailey, Charles A.; Harrison, F. A.; Stern, D.; Zhang, W. W.

In: Monthly Notices of the Royal Astronomical Society, Vol. 463, No. 3, 2016, p. 2612-2622.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - The NuSTAR view of the non-thermal emission from PSR J0437-4715

AU - Guillot, S.

AU - Kaspi, V M

AU - Archibald, Robert F.

AU - Bachetti, M.

AU - Flynn, J.C.

AU - Jankowski, F.

AU - Bailes, M.

AU - Boggs, S.

AU - Christensen, Finn Erland

AU - Craig, W. W.

AU - Hailey, Charles A.

AU - Harrison, F. A.

AU - Stern, D.

AU - Zhang, W. W.

N1 - This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. ©:2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

PY - 2016

Y1 - 2016

N2 - We present a hard X-ray Nuclear Spectroscopic Telescope Array (NuSTAR) observation of PSR J0437-4715, the nearest millisecond pulsar. The known pulsations at the apparent pulse period similar to 5.76 ms are observed with a significance of 3.7 sigma, at energies up to 20 keV above which the NuSTAR background dominates. We measure a photon index Gamma = 1.50 +/- 0.25 (90 per cent confidence) for the power-law fit to the non-thermal emission. It had been shown that spectral models with two or three thermal components fit the XMM-Newton spectrum of PSR J0437-4715, depending on the slope of the power-law component, and the amount of absorption of soft X-rays. The new constraint on the high-energy emission provided by NuSTAR removes ambiguities regarding the thermal components of the emission below 3 keV. We performed a simultaneous spectral analysis of the XMM-Newton and NuSTAR data to confirm that three thermal components and a power law are required to fit the 0.3-20 keV emission of PSR J0437-4715. Adding a ROSAT-PSPC spectrum further confirmed this result and allowed us to better constrain the temperatures of the three thermal components. A phase-resolved analysis of the NuSTAR data revealed no significant change in the photon index of the high-energy emission. This NuSTAR observation provides further impetus for future observations with the NICER mission (Neutron Star Interior Composition Explorer) whose sensitivity will provide much stricter constraints on the equation of state of nuclear matter by combining model fits to the pulsar's phase-folded light curve with the pulsar's well-defined mass and distance from radio timing observations.

AB - We present a hard X-ray Nuclear Spectroscopic Telescope Array (NuSTAR) observation of PSR J0437-4715, the nearest millisecond pulsar. The known pulsations at the apparent pulse period similar to 5.76 ms are observed with a significance of 3.7 sigma, at energies up to 20 keV above which the NuSTAR background dominates. We measure a photon index Gamma = 1.50 +/- 0.25 (90 per cent confidence) for the power-law fit to the non-thermal emission. It had been shown that spectral models with two or three thermal components fit the XMM-Newton spectrum of PSR J0437-4715, depending on the slope of the power-law component, and the amount of absorption of soft X-rays. The new constraint on the high-energy emission provided by NuSTAR removes ambiguities regarding the thermal components of the emission below 3 keV. We performed a simultaneous spectral analysis of the XMM-Newton and NuSTAR data to confirm that three thermal components and a power law are required to fit the 0.3-20 keV emission of PSR J0437-4715. Adding a ROSAT-PSPC spectrum further confirmed this result and allowed us to better constrain the temperatures of the three thermal components. A phase-resolved analysis of the NuSTAR data revealed no significant change in the photon index of the high-energy emission. This NuSTAR observation provides further impetus for future observations with the NICER mission (Neutron Star Interior Composition Explorer) whose sensitivity will provide much stricter constraints on the equation of state of nuclear matter by combining model fits to the pulsar's phase-folded light curve with the pulsar's well-defined mass and distance from radio timing observations.

U2 - 10.1093/mnras/stw2194

DO - 10.1093/mnras/stw2194

M3 - Journal article

VL - 463

SP - 2612

EP - 2622

JO - Royal Astronomical Society. Monthly Notices

JF - Royal Astronomical Society. Monthly Notices

SN - 0035-8711

IS - 3

ER -

Guillot S, Kaspi VM, Archibald RF, Bachetti M, Flynn JC, Jankowski F et al. The NuSTAR view of the non-thermal emission from PSR J0437-4715. Monthly Notices of the Royal Astronomical Society. 2016;463(3):2612-2622. https://doi.org/10.1093/mnras/stw2194