Abstract
| Original language | English |
|---|---|
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 478 |
| Issue number | 1 |
| Pages (from-to) | 448-459 |
| ISSN | 0035-8711 |
| DOIs | |
| Publication status | Published - 2018 |
Bibliographical note
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. ©: 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.Keywords
- Stars: neutron
- pulsars: individual: GX 1+4
- X-rays: stars
Cite this
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A curious case of the accretion-powered X-ray pulsar GX 1+4. / Jaisawal, Gaurava K.; Naik, Sachindra; Gupta, Shivangi; Chenevez, Jérôme; Epili, Prahlad.
In: Monthly Notices of the Royal Astronomical Society, Vol. 478, No. 1, 2018, p. 448-459.Research output: Contribution to journal › Journal article › Research › peer-review
TY - JOUR
T1 - A curious case of the accretion-powered X-ray pulsar GX 1+4
AU - Jaisawal, Gaurava K.
AU - Naik, Sachindra
AU - Gupta, Shivangi
AU - Chenevez, Jérôme
AU - Epili, Prahlad
N1 - This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. ©: 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
PY - 2018
Y1 - 2018
N2 - We present detailed spectral and timing studies using a NuSTAR observation of GX 1+4 in 2015 October during an intermediate-intensity state. The measured spin period of 176.778 s is found to be one of the highest values since its discovery. In contrast to a broad sinusoidal-like pulse profile, a peculiar sharp peak is observed in profiles below ∼25 keV. The profiles at higher energies are found to be significantly phase shifted compared to the soft X-ray profiles. Broad-band energy spectra of GX 1+4, obtained from NuSTAR and Swift observations, are described with various continuum models. Among these, a two-component model consisting of a bremsstrahlung and a blackbody component is found to best fit the phase-averaged and phase-resolved spectra. Physical models are also used to investigate the emission mechanism in the pulsar, which allows us to estimate the magnetic field strength to be in ∼(5–10) × 1012 G range. Phase-resolved spectroscopy of NuSTAR observation shows a strong blackbody emission component in a narrow pulse phase range. This component is interpreted as the origin of the peculiar peak in the pulse profiles below ≤25 keV. The size of emitting region is calculated to be ∼400 m. The bremsstrahlung component is found to dominate in hard X-rays and explains the nature of simple profiles at high energies.
AB - We present detailed spectral and timing studies using a NuSTAR observation of GX 1+4 in 2015 October during an intermediate-intensity state. The measured spin period of 176.778 s is found to be one of the highest values since its discovery. In contrast to a broad sinusoidal-like pulse profile, a peculiar sharp peak is observed in profiles below ∼25 keV. The profiles at higher energies are found to be significantly phase shifted compared to the soft X-ray profiles. Broad-band energy spectra of GX 1+4, obtained from NuSTAR and Swift observations, are described with various continuum models. Among these, a two-component model consisting of a bremsstrahlung and a blackbody component is found to best fit the phase-averaged and phase-resolved spectra. Physical models are also used to investigate the emission mechanism in the pulsar, which allows us to estimate the magnetic field strength to be in ∼(5–10) × 1012 G range. Phase-resolved spectroscopy of NuSTAR observation shows a strong blackbody emission component in a narrow pulse phase range. This component is interpreted as the origin of the peculiar peak in the pulse profiles below ≤25 keV. The size of emitting region is calculated to be ∼400 m. The bremsstrahlung component is found to dominate in hard X-rays and explains the nature of simple profiles at high energies.
KW - Stars: neutron
KW - pulsars: individual: GX 1+4
KW - X-rays: stars
U2 - 10.1093/mnras/sty1049
DO - 10.1093/mnras/sty1049
M3 - Journal article
VL - 478
SP - 448
EP - 459
JO - Royal Astronomical Society. Monthly Notices
JF - Royal Astronomical Society. Monthly Notices
SN - 0035-8711
IS - 1
ER -