A broad-band look of the accreting millisecond X-ray pulsar SAX J1748.9−2021 using AstroSat and XMM–Newton

Sharma, Rahul; Beri, Aru; Sanna, A.; Dutta, A.

doi:10.1093/mnras/staa109

Cited by 22 publications

(13 citation statements)

References 65 publications

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“…Residuals around 30 keV due to the Xenon calibration edge (Antia et al 2017) were observed in the LAXPC20 spectra and were modeled using a Gaussian. A similar feature has also been found in the LAXPC spectra of other sources (see e.g., Sharma et al 2020;Banerjee et al 2020). We also added a larger systematic (3%) value to account for uncertainties in response calibration over such a wide energy band 4-70 keV (see e.g., Mudambi et al 2020).…”

Section: Spectral Analysis and Resultssupporting

confidence: 79%

AstroSat observations of the first Galactic ULX pulsar Swift J0243.6+6124

Beri

Naik

Singh

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Swift J0243.6+6124, the first Galactic ultra-luminous X-ray pulsar, was observed during its 2017-2018 outburst with AstroSat at both sub- and super-Eddington levels of accretion with X-ray luminosities of LX ∼ 7 × 1037 and 6 × 1038 ergs−1, respectively. Our broadband timing and spectral observations show that X-ray pulsations at ${\sim } 9.85 \rm {s}$ have been detected up to 150 keV when the source was accreting at the super-Eddington level. The pulse profiles are a strong function of both energy and source luminosity, showing a double-peaked profile with pulse fraction increasing from ∼ $10{\%}$ at $1.65 \rm {keV}$ to 40–80 % at $70 \rm {keV}$. The continuum X-ray spectra are well-modeled with a high energy cut-off power law (Γ ∼ 0.6-0.7) and one or two blackbody components with temperatures of ∼ 0.35 $\rm {keV}$ and $1.2 \rm {keV}$, depending on the accretion level. No iron line emission is observed at sub-Eddington level, while a broad emission feature at around 6.9 keV is observed at the super-Eddington level, along with a blackbody radius ($121-142 \rm {km}$) that indicates the presence of optically thick outflows.

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Section: Spectral Analysis and Resultssupporting

confidence: 79%

AstroSat observations of the first Galactic ULX pulsar Swift J0243.6+6124

Beri

Naik

Singh

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…We estimated the magnetic field strength to lie between 2.7×10 8 < B < 2.5×10 9 G, for the disc truncating between 31 < R in < 111 km. This limit on the magnetic field is consistent with the typical limit of magnetic field for the NS LMXBs (B 10 9 G) and AMXPs (Cackett et al 2009;Mukherjee et al 2015;Ludlam et al 2016;Sharma et al 2020).…”

Section: Discussionsupporting

confidence: 87%

Broad-band spectral analysis of LMXB XTE J1710-281 with Suzaku

Sharma,

Jain

et al. 2020

Preprint

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This work presents the broad-band time-averaged spectral analysis of neutron star low-mass X-ray binary, XTE J1710-281 by using the Suzaku archival data. The source was in a hard or an intermediate spectral state during this observation. This is the first time that a detailed spectral analysis of the persistent emission spectra of XTE J1710-281 has been done up to 30 keV with improved constraints on its spectral parameters. By simultaneously fitting the XIS (0.6-9.0 keV) and the HXD-PIN (15.0-30.0 keV) data, we have modelled the persistent spectrum of the source with models comprising a soft component from accretion disc and/or neutron star surface/boundary layer and a hard Comptonizing component. The 0.6-30 keV continuum with neutral absorber can be described by a multi-colour disc blackbody with an inner disc temperature of kT disc = 0.28 keV, which is significantly Comptonized by the hot electron cloud with electron temperature of kT e ≈ 5 keV and described by photon index Γ = 1.86. A more complex three-component model comprising a multi-colour disc blackbody ≈ 0.30 keV, single temperature blackbody ≈ 0.65 keV and Comptonization from the disc, partially absorbed (about 38 per cent) by an ionized absorber (log(ξ) ≈ 4) describes the broadband spectrum equally well.

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“…AstroSat science instruments, including SXT, are ideal to study various spectral and timing properties of neutron star LMXBs, and their evolution. For example, the combined spectra from AstroSat (SXT+LAXPC) and XMM-Newton (EPIC-PN) observations of the neutron star LMXB SAX J1748.9-2021 suggested the presence of reflection features (Sharma et al, 2020). Fig.…”

Section: Neutron Star Low-mass X-ray Binariesmentioning

confidence: 98%

Science with the AstroSat Soft X-ray telescope: An overview

et al. 2021

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The Soft X-ray Telescope (SXT) aboard the AstroSat satellite is the first Indian X-ray telescope in space. It is a modest size X-ray telescope with a charge coupled device (CCD) camera in the focal plane, which provides X-ray images in the ∼ 0.3 − 8.0 keV band. A forte of SXT is in providing undistorted spectra of relatively bright X-ray sources, in which it excels some current large CCD-based X-ray telescopes. Here, we highlight some of the published spectral and timing results obtained using the SXT data to demonstrate the capabilities and overall performance of this telescope.

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A broad-band look of the accreting millisecond X-ray pulsar SAX J1748.9−2021 using AstroSat and XMM–Newton

Cited by 22 publications

References 65 publications

AstroSat observations of the first Galactic ULX pulsar Swift J0243.6+6124

AstroSat observations of the first Galactic ULX pulsar Swift J0243.6+6124

Broad-band spectral analysis of LMXB XTE J1710-281 with Suzaku

Science with the AstroSat Soft X-ray telescope: An overview

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