A Suzaku view of IGR J16393–4643

Islam, Nazma; Maitra, Chandreyee; Pradhan, Pragati; Paul, Biswajit

doi:10.1093/mnras/stu2395

Cited by 17 publications

(33 citation statements)

References 23 publications

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“…However, hard X-ray eclipses are always known to be sharp. IGR J16393-4643 is an unusual HMXB system with a neutron star that shows a gradual and partial eclipse even in the hard X-rays (Islam et al 2015). IGR J16393-4643 was detected in the INTEGRAL survey of the galactic plane and was identified to be the same source as AX J1639.0-4642, discovered earlier with ASCA observatory (Bird et al 2004;Sugizaki et al 2001).…”

Section: Introductionmentioning

confidence: 84%

Investigating a unique partial eclipse in the high-mass X-ray binary IGR J16393−4643 with Swift-XRT

Kabiraj

Islam

Paul

2019

Monthly Notices of the Royal Astronomical Society

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The orbital profile of the High Mass X-ray binary IGR J16393-4643 shows a dip in its X-ray intensity, which was previously interpreted as an eclipse. Unlike most eclipsing HMXBs, where the X-ray eclipses are about two orders of magnitude fainter compared to the out of eclipse emission, this particular eclipse like feature is narrow and partial, casting doubt if it is indeed an eclipse. To further investigate the nature of this low intensity orbital phase, we use a large number of observations with Swift-XRT, covering the entire orbital phase. The soft X-ray observations also show this low intensity phase, which is about 30% of the intensity during rest of the orbit. We also carried out orbital phase resolved spectroscopy to compare the change in the spectral parameters inside and outside of this low intensity state. The results indicate that this low intensity state might not be an eclipse, as previously thought but absorption in the stellar corona. We have also provided the inclination angle of the binary for grazing eclipse caused by the stellar corona.

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Section: Introductionmentioning

confidence: 84%

Investigating a unique partial eclipse in the high-mass X-ray binary IGR J16393−4643 with Swift-XRT

Kabiraj

Islam

Paul

2019

Monthly Notices of the Royal Astronomical Society

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“…The source is a highly absorbed (N H ≈ 2.5 × 10 23 cm −2 Bodaghee et al, 2006) pulsar with a spin period of 911s . The orbital period is under debate with a most likely value of 4.24d (Pearlman et al, 2011;Thompson et al, 2006;Islam et al, 2015). The companion is not yet identified (Bodaghee et al, 2012a) but its dynamical mass is estimated as > 7.5M ⊙ (Pearlman et al, 2011;Nespoli et al, 2010a;Chaty et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

High-mass X-ray binaries in the Milky Way

Walter

Lutovinov

Bozzo

et al. 2015

Astron Astrophys Rev

230

234

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High-mass X-ray binaries are fundamental in the study of stellar evolution, nucleosynthesis, structure and evolution of galaxies and accretion processes. Hard X-rays observations by INTEGRAL and Swift have broadened significantly our understanding in particular for the super-giant systems in the Milky Way, which number has increased by almost a factor of three. INTEGRAL played a crucial role in the discovery, study and understanding of heavily obscured systems and of fast X-ray transients. Most super-giant systems can now be classified in three categories: classical/obscured, eccentric and fast transient.The classical systems feature low eccentricity and variability factor of ∼ 10 3 , mostly driven by hydrodynamic phenomena occurring on scales larger than the accretion radius. Among them, systems with short orbital periods and close to Roche-Lobe overflow or with slow winds, appear highly obscured. In eccentric systems, the variability amplitude can reach even higher factors, because of the contrast of the wind density along the orbit. Four super-giant systems, featuring fast outbursts, very short orbital periods and anomalously low accretion rates, are not yet understood.Simulations of the accretion processes on relatively large scales have progressed and reproduce parts of the observations. The combined effects of wind

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“…Using the same response and background files, and adopting the same exposure times as the real data, we simulated 10,000 sets of XMM-Newton (pn and combined MOS1+MOS2) and NuSTAR (FPMA and FPMB) spectra with the FAKEIT command in XSPEC based on the best-3 We have also tried replacing the CUTOFFPL model with the FD-CUT and NPEX models also frequently applied to Galactic neutron stars (e.g. Odaka et al 2013;Fürst et al 2013;Islam et al 2015;Vybornov et al 2017), but these provide identical fits to the CUTOFFPL model, so we do not present the results in full.…”

Section: Time-averaged Spectroscopymentioning

confidence: 99%

Super-Eddington accretion on to the neutron star NGC 7793 P13: Broad-band X-ray spectroscopy and ultraluminous X-ray sources

Walton

Fürst

Harrison

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We present a detailed, broadband X-ray spectral analysis of the ULX pulsar NGC 7793 P13, a known super-Eddington source, utilizing data from the XMM-Newton, NuSTAR and Chandra observatories. The broadband XMM-Newton+NuSTAR spectrum of P13 is qualitatively similar to the rest of the ULX sample with broadband coverage, suggesting that additional ULXs in the known population may host neutron star accretors. Through time-averaged, phaseresolved and multi-epoch studies, we find that two non-pulsed thermal blackbody components with temperatures ∼0.5 and 1.5 keV are required to fit the data below 10 keV, in addition to a third continuum component which extends to higher energies and is associated with the pulsed emission from the accretion column. The characteristic radii of the thermal components appear to be comparable, and are too large to be associated with the neutron star itself, so the need for two components likely indicates the accretion flow outside the magnetosphere is complex. We suggest a scenario in which the thick inner disc expected for super-Eddington accretion begins to form, but is terminated by the neutron star's magnetic field soon after its onset, implying a limit of B 6 × 10 12 G for the dipolar component of the central neutron star's magnetic field. Evidence of similar termination of the disc in other sources may offer a further means of identifying additional neutron star ULXs. Finally, we examine the spectrum exhibited by P13 during one of its unusual 'off' states. These data require both a hard powerlaw component, suggesting residual accretion onto the neutron star, and emission from a thermal plasma, which we argue is likely associated with the P13 system.

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A Suzaku view of IGR J16393–4643

Cited by 17 publications

References 23 publications

Investigating a unique partial eclipse in the high-mass X-ray binary IGR J16393−4643 with Swift-XRT

Investigating a unique partial eclipse in the high-mass X-ray binary IGR J16393−4643 with Swift-XRT

High-mass X-ray binaries in the Milky Way

Super-Eddington accretion on to the neutron star NGC 7793 P13: Broad-band X-ray spectroscopy and ultraluminous X-ray sources

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