Spectral evolution of the supergiant HMXB IGR J16320–4751 along its orbit using <i>XMM-Newton</i>

García, Federico; Fogantini, Federico A.; Chaty, S.; Combi, J. A.

doi:10.1051/0004-6361/201833365

Cited by 16 publications

(31 citation statements)

References 26 publications

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“…The linear behaviour in non-eclipsing phases suggests that the Fe line emission region follows closely the NS orbital motion. 1975), one can model the absorption orbital modulation by integrating the wind density profile along the line of sight for each orbital phase (see García et al 2018, for a full description on this procedure). However, for a very low eccentricity binary like IGR J18027-2016 , this method would produce a symmetrical absorption profile with respect to the eclipse mid-phase, which is in disagreement with the asymmetric absorption eclipse profile from IGR J18027-2016 , as shown in Figure 5.…”

Section: Discussionmentioning

confidence: 99%

“…The classical picture of sgXBs involve a compact object (CO), typically a neutron star (NS) in a close orbit around a supergiant early star which has a strong wind embedding it and from which the CO is constantly accreting. By considering a simple spherical wind (Castor-Abbott-Klein (CAK), Castor et al 1975), one can model the absorption orbital modulation by integrating the wind density profile along the line of sight for each orbital phase (see García et al 2018, for a full description on this procedure). However, for a very low eccentricity binary like IGR J18027-2016 , this method would produce a symmetrical absorption profile with respect to the eclipse mid-phase, which is in disagreement with the asymmetric absorption eclipse profile from IGR J18027-2016 , as shown in Figure 5.…”

Section: Discussionmentioning

confidence: 99%

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Stellar wind structures in the eclipsing binary system IGR J18027–2016

Fogantini

García

Combi

et al. 2021

A&A

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Context. IGR J18027–2016 is an obscured high-mass X-ray binary formed by a neutron star accreting from the wind of a supergiant companion with a ∼4.57 d orbital period. The source shows an asymmetric eclipse profile that remained stable across several years. Aims. We aim to investigate the geometrical and physical properties of stellar wind structures formed by the interaction between the compact object and the supergiant star. Methods. In this work we analysed the temporal and spectral evolution of this source along its orbit using six archival XMM-Newton observations and the accumulated Swift/BAT hard X-ray light curve. Results. The XMM-Newton light curves show that the source hardens during the ingress and egress of the eclipse, in accordance with the asymmetric profile seen in Swift/BAT data. A reduced pulse modulation is observed on the ingress to the eclipse. We modelled XMM-Newton spectra by means of a thermally Comptonized continuum (NTHCOMP), adding two Gaussian emission lines corresponding to Fe Kα and Fe Kβ. We included two absorption components to account for the interstellar and intrinsic media. We found that the local absorption column outside the eclipse fluctuates uniformly around ∼6 × 1022 cm−2, whereas when the source enters and leaves the eclipse the column increases by a factor of ≳3, reaching values up to ∼35 and ∼15 × 1022 cm−2, respectively. Conclusions. Combining the physical properties derived from the spectral analysis, we propose a scenario in which, primarily, a photo-ionisation wake and, secondarily, an accretion wake are responsible for the orbital evolution of the absorption column, continuum emission, and variability seen at the Fe-line complex.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Stellar wind structures in the eclipsing binary system IGR J18027–2016

Fogantini

García

Combi

et al. 2021

A&A

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“…Although classic SgXBs such as Vela X-1 are largely circularized, SFXTs exhibit more eccentric orbits and would benefit from such an extension. For instance, the N H profile obtained by García et al (2018) in the SFXT IGR J16320-4751 displays a very sharp increase which the authors interpret as due to a grazing orbit. In addition, the flat N H profile they measure away from this spike can only be reproduced either with a low inclination, incompatible with a grazing orbit, or with an eccentric orbit.…”

Section: Eccentric Orbitsmentioning

confidence: 96%

Radiography in high mass X-ray binaries

Mellah

Grinberg

Sundqvist

et al. 2020

A&A

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Context. In high mass X-ray binaries, an accreting compact object orbits a high mass star, which loses mass through a dense and inhomogeneous wind. Aims. Using the compact object as an X-ray backlight, the time variability of the absorbing column density in the wind can be exploited in order to shed light on the micro-structure of the wind and obtain unbiased stellar mass-loss rates for high mass stars. Methods. We developed a simplified representation of the stellar wind where all the matter is gathered in spherical “clumps” that are radially advected away from the star. This model enables us to explore the connections between the stochastic properties of the wind and the variability of the column density for a comprehensive set of parameters related to the orbit and to the wind micro-structure, such as the size of the clumps and their individual mass. In particular, we focus on the evolution with the orbital phase of the standard deviation of the column density and of the characteristic duration of enhanced absorption episodes. Using the porosity length, we derive analytical predictions and compare them to the standard deviations and coherence time scales that were obtained. Results. We identified the favorable systems and orbital phases to determine the wind micro-structure. The coherence time scale of the column density is shown to be the self-crossing time of a single clump in front of the compact object. We thus provide a procedure to get accurate measurements of the size and of the mass of the clumps, purely based on the observable time variability of the column density. Conclusions. The coherence time scale grants direct access to the size of the clumps, while their mass can be deduced separately from the amplitude of the variability. We further show how monitoring the variability at superior conjunctions can probe the onset of the clump-forming region above the stellar photosphere. If the high column density variations in some high mass X-ray binaries are due to unaccreted clumps which are passing by the line-of-sight, this would require high mass clumps to reproduce the observed peak-to-peak amplitude and coherence time scales. These clump properties are marginally compatible with the ones derived from radiative-hydrodynamics simulations. Alternatively, the following components could contribute to the variability of the column density: larger orbital scale structures produced by a mechanism that has yet to be identified or a dense environment in the immediate vicinity of the accretor, such as an accretion disk, an outflow, or a spherical shell surrounding the magnetosphere of the accreting neutron star.

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“…IGR J16318-4848, with a likely long orbital period of ∼ 80 days (Iyer and Paul, 2017), is in the Norma spiral arm region of the Galaxy, and further soft X-ray observations uncovered more HMXBs in this region. Although we still do not know the nature of the compact object in IGR J16318-4848, IGR J16320-4751 was found to be an HMXB with a slowly rotating (1300 sec period) neutron star using XMM observations (Lutovinov et al, 2005b;García et al, 2018). Additional IGR HMXBs were uncovered in the Norma region as well as other part of the Galaxy, using Chandra localizations and information about the optical or near-IR counterpart (Tomsick et al, 2006(Tomsick et al, , 2008(Tomsick et al, , 2009(Tomsick et al, , 2012a(Tomsick et al, , 2016(Tomsick et al, , 2020.…”

Section: Soft X-ray Campaignsmentioning

confidence: 99%

15 years of Galactic surveys and hard X-ray Background measurements

Krivonos,

Bird,

Churazov

et al. 2021

Preprint

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The INTEGRAL hard X-ray surveys have proven to be of fundamental importance. INTEGRAL has mapped the Galactic plane with its large field of view and excellent sensitivity. Such hard X-ray snapshots of the whole Milky Way on a time scale of a year are beyond the capabilities of past and current narrow-FOV grazing incidence X-ray telescopes. By expanding the INTEGRAL X-ray survey into shorter timescales, a productive search for transient X-ray emitters was made possible. In more than fifteen years of operation, the INTEGRAL observatory has given us a sharper view of the hard X-ray sky, and provided the triggers for many followup campaigns from radio frequencies to gamma-rays. In addition to conducting a census of hard X-ray sources across the entire sky, INTEGRAL has carried out, through Earth occultation maneuvers, unique observations of the large-scale cosmic X-ray background, which will without question be included in the annals of X-ray astronomy as one of the mission's most salient contribution to our understanding of the hard X-ray sky.

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Spectral evolution of the supergiant HMXB IGR J16320–4751 along its orbit using XMM-Newton

Cited by 16 publications

References 26 publications

Stellar wind structures in the eclipsing binary system IGR J18027–2016

Stellar wind structures in the eclipsing binary system IGR J18027–2016

Radiography in high mass X-ray binaries

15 years of Galactic surveys and hard X-ray Background measurements

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