<i>AstroSat</i> observations of the first Galactic ULX pulsar Swift J0243.6+6124

Beri, Aru; Naik, Sachindra; Singh, K. P.; Jaisawal, Gaurava K.; Bhattacharyya, Sudip; Charles, P. A.; Ho, Wynn C. G.; Maitra, Chandreyee; Bhattacharya, Dipankar; Dewangan, G. C.; Middleton, Matthew; Altamirano, D.; Gandhi, P.; Raichur, Harsha

doi:10.1093/mnras/staa3254

Cited by 22 publications

(14 citation statements)

References 49 publications

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“…The characterization of the first Galactic ULP, Swift J0243.6+6124, can therefore be extremely useful to understand this important class of sources. AstroSat observed the 2017-2018 outburst of Swift J0243.6+6124, and characterized its broadband spectrum, as well as energy-dependent and luminosity-dependent pulse profiles in the energy range of 0.3 − 150 keV (Beri et al, 2021). SXT was particularly useful to measure the continuum spectrum, as well as pulse profiles (see Fig.…”

Section: Ultra-luminous X-ray Pulsarsmentioning

confidence: 99%

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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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Section: Ultra-luminous X-ray Pulsarsmentioning

confidence: 99%

“…Energy-resolved pulse profile of the first Galactic ultra-luminous X-ray pulsar Swift J0243.6+6124, using the AstroSat SXT data. This figure shows that SXT could sufficiently resolve the X-ray pulsation period of ∼ 9.85 s in its FW mode (see section 5.; figure courtesy: Aru Beri;Beri et al, 2021).…”

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confidence: 99%

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

et al. 2021

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“…We have included the different observations for each source, while the only observed parameters with notable differences are included, and in the calculations, we avoid using Ṗ computed based on just comparing two spin period or long timescale average measurements (marked with * ). Since the observation information and parameters are not complete, many other measured data [34,35,14,36,37,38,39] are not listed.…”

Section: Observations Of the Rotational Behaviors For Different Sourcesmentioning

confidence: 99%

“…• Swift J0243.6+6124 is the only detected ULX pulsar in the Milky Way. It underwent an outburst which started in October 2017, and reached its peak flux on November [39,43,47,48,35]. The spin period was around 9.84 s with a period derivative of ∼ 10 −9 − 10 −8 s s −1 [39].…”

Section: Observations Of the Rotational Behaviors For Different Sourcesmentioning

confidence: 99%

Studying magnetic fields of ultraluminous X-ray pulsars using different accretion torques

Chen¹,

Wang²,

Tong³

2021

Preprint

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The magnetic field of ultraluminous X-ray (ULX) pulsars is the key parameter to understand the nature and accretion physics. However, the typical magnetic field values in these ULX pulsars are still under debate. We used six different torque models to study the magnetic fields of ULX pulsars, to see how derived magnetic fields change with different models, and to determine which models are more suitable for ULX pulsars. We took the currently available period, period derivative, and flux data of 7 confirmed ULX pulsars, M82 X-2, ULX NGC 7793 P13, ULX NGC 5907, NGC 300 ULX1, NGC 1313 X-2, M51 ULX-7, Swift J0243.6+6124, plus one potential ULX pulsars, SMC X-3. The magnetic fields of these ULX pulsars were constrained from two physical conditions: the spin-up process and near equilibrium. We checked possible dependence of the magnetic field estimations on the different torque models. The calculations suggest the accretion torque models by Ghosh & Lamb [1], Wang [2], Kluźniak & Rappaport [3] and Campbell [4] are more likely to support magnetar models for ULX pulsars, while Lovelace, Romanova & Bisnovatyi-Kogan [5]'s model generally predicts the magnetic field in normal neutron stars. Implications of our results combined with other independent methods are also discussed, which will help us to understand the nature and rotational behavior of these ULX pulsars.

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“…So far, the presence of NSs in six ULXs has been confirmed by pulse detections and are known as pulsating ULXs (PULXs): M82 X2 (Bachetti et al 2014), NGC 7793 P13 (Fürst et al 2016), NGC 5907 ULX-1 (Israel et al 2017a,b), NGC 300 ULX-1 (Carpano et al 2018), NGC 1313 X-2 (Sathyaprakash et al 2019) and M51 ULX-7 (Rodríguez Castillo et al 2020). In addition, the first Galactic PULX (Swift J0243.6+6124) was observed during its outburst by AstroSat (Beri et al 2021).…”

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confidence: 99%

The Transient Ultra-luminous X-ray Source, ULX-4, in M51

Allak,

Akyuz,

Oralhan

et al. 2021

Preprint

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We present the results of a temporal and spectral analysis of the transient source ULX-4 in the galaxy M51. The data used were drawn from Chandra, XMM-Newton and Swift-XRT archives, spanning the years 2000-2019. The X-ray flux of the source is seen to vary by two orders of magnitudes within a month but a short-term variability was not observed. We find some evidence for the existence of a bi-modality feature in the flux distribution of ULX-4. The X-ray spectra from most of the data can be fitted by a simple power-law with a photon index in the range 1.44 -2.0 suggesting that the source is in a hard state characterized by non-thermal emission. The presence of a soft component, in two XMM-Newton observations, is best described by the addition of a mekal component suggesting a contribution from a diffuse background source. We identified two optical sources as possible counterparts within an error radius of 0. 18 at 95% confidence level for ULX-4 based on the archival HST/ACS (Hubble Space Telescope/Advanced Camera for Surveys) and HST/WFC3 (The Wide Field Camera 3) data. The absolute magnitude (M V ) of these counterparts is −6.6 mag. Blackbody fits of the spectral energy distributions (SEDs) indicate the spectral type to be B-type stars. One of these counterparts exhibits a low-amplitude optical periodicity of 264 ± 37 days in the F606W filter; If we assume this apparent periodicity is associated with the orbital motion of the donor, then it is more likely that the donor is a red supergiant (RSG) satisfying the long periodicity and accretion via Roche-lobe overflow. Consequently, the SED would then have to be interpreted as a superposition of emissions from a cold donor and a hot flow component, most likely from an accretion disk. If, on the other hand, the periodicity is super orbital in nature i.e., due to possible interactions of the compact object with a circumstellar disk, the donor could then be a Be/X star hosting a neutron star (NS).

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

Cited by 22 publications

References 49 publications

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

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

Studying magnetic fields of ultraluminous X-ray pulsars using different accretion torques

The Transient Ultra-luminous X-ray Source, ULX-4, in M51

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