Discovery of X-ray absorption features from the dipping low-mass X-ray binary XB 1916-053 with XMM-Newton

Boirin, L.; Parmar, A. N.; Barret, D.; Paltani, S.; Grindlay, Jonathan E.

doi:10.1051/0004-6361:20034550

Cited by 60 publications

(97 citation statements)

References 46 publications

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“…This excess consisted of a "Gaussianlike" component centred at ∼1 keV. This feature has been previously modelled in a number of sources either as an emission line or as an edge, and its nature is unclear (e.g., Sidoli et al 2001;Boirin & Parmar 2003;Boirin et al 2004Boirin et al , 2005. If the feature has an astrophysical origin, its energy is consistent with Ne x or a blend of Fe xx-Fe xxiv emission.…”

Section: X-ray Spectramentioning

confidence: 97%

A systematic analysis of the broad iron Kαline in neutron-star LMXBs withXMM-Newton

Trigo

Bel

et al. 2010

A&A

163

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We analysed the XMM-Newton archival observations of 16 neutron star (NS), low-mass X-ray binaries (LMXBs) to study the Fe K emission in these objects. The sample includes all the observations of NS LMXBs performed in EPIC pn timing mode with XMM-Newton publicly available until September 30, 2009. We performed a detailed data analysis considering pile-up and background effects. The properties of the Fe lines differed from previous published analyses because of either incorrect pile-up corrections or different continuum parameterisation. Eighty percent of the observations for which a spectrum can be extracted showed significant Fe line emission. We found an average line centroid of 6.67 ± 0.02 keV and a finite width, σ, of 0.33 ± 0.02 keV. The equivalent width of the lines varied between 17 and 189 eV, with an average weighted value of 42 ± 3 eV. For sources where several observations were available, the Fe line parameters changed between observations whenever the continuum changed significantly. The line parameters did not show any correlation with luminosity. Most important, we could fit the Fe line with a simple Gaussian component for all the sources. The lines did not show the asymmetric profiles that were interpreted as indicating relativistic effects in previous analyses of these LMXBs.

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Section: X-ray Spectramentioning

confidence: 97%

A systematic analysis of the broad iron Kαline in neutron-star LMXBs withXMM-Newton

Trigo

Bel

et al. 2010

A&A

163

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“…Table 1 is an updated version of the Table 5 from Boirin et al (2004). In the past research, most objects were fitted using powerlaw model to describe a continuum and a Gaussian shape for lines.…”

Section: Narrow Fe Absorption Lines In X-ray Binariesmentioning

confidence: 99%

“…The extreme case is XB1916-053, where He-like iron line changes its EW during the persistent and dipping time intervals. In the persistent phase, EW = −30 +8 −12 , while during the dipping phase the EW changes from EW = −74 +20 −27 to EW = −168 +44 −46 (Boirin et al 2004). A summary of the objects with absorption lines and the connection of EWs with spectral state is shown in Ponti et al (2012).…”

Section: Narrow Fe Absorption Lines In X-ray Binariesmentioning

confidence: 99%

“…Recently, several X-ray binaries have exhibited absorption lines from highly ionized iron (Boirin et al 2004;Kubota et al 2007;Díaz Trigo et al 2012). Many of those sources show dips in their light curves, which are believed to be caused by obscuration of the central X-ray source by a dense material located at the outer edge of an accretion disk.…”

Section: Introductionmentioning

confidence: 99%

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Disk emission and atmospheric absorption lines in black hole candidate 4U 1630-472

Różáńska

Madej

Bagińska

et al. 2014

A&A

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Context. We analyzed Suzaku data of the black hole candidate 4U 1630-472 when it was in the high/soft state. The source, known for X-ray outbursts and for absorption dips, has an X-ray continuum spectrum that is interpreted correctly as emission from an accretion disk. Additionally, two absorption lines from He and H-like iron have been clearly detected in the high-resolution data from 4U 1630-472. Aims. We show that the continuum X-ray spectrum of 4U 1630-472 with iron absorption lines can be satisfactorily modeled by the spectrum from an accretion disk atmosphere. Absorption lines of highly ionized iron originating in a hot accretion-disk atmosphere can be an alternative or complementary explanation to the wind model usually favored for this type of sources. Methods. We performed full radiative transfer calculations to model the emission from an accretion disk surface that is seen at different viewing angles using our transfer code ATM21. Computed models are then fitted to high-resolution X-ray spectra of 4U 1630-472 obtained by the Suzaku satellite. Results. We modeled continuum and line spectra using a single model. Absorption lines of highly ionized iron can originate in the upper parts of the disk atmosphere, which is intrinsically hot because of the high disk temperature. Iron line profiles computed with natural, thermal, and pressure broadenings match observations very well. Conclusions. According to any global disk models considered for the mass of central object that is close to 10 M or less, the effective temperature of the inner radii reaches 10 7 K. We showed that the accretion disk atmosphere can effectively produce iron absorption lines observed in 4U 1630-472 spectrum. Absorption line arising in an accretion disk atmosphere is the important part of the observed line profile, even if there are also other mechanisms responsible for the absorption features. Nevertheless, the wind theory can be an artefact of the fitting procedure when the continuum and lines are fitted as separate model components.

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“…GX 13+1 is unusual in that all other LMXB systems that exhibit prominent Fe xxv and Fe xxvi features are dipping sources (see Table 5 of Boirin et al 2004). Dipping sources are LMXB A&A 543, A50 (2012) Notes.…”

Section: Introductionmentioning

confidence: 99%

XMM-Newtonobservations of GX 13 + 1: correlation between photoionised absorption and broad line emission

Trigo¹,

Sidoli

Boirin

et al. 2012

A&A

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We analysed data from five XMM-Newton observations of GX 13+1 to investigate the variability of the photo-ionised absorber in this source. We fitted EPIC and RGS spectra obtained from the "least-variable" intervals with a model consisting of disc-blackbody and blackbody components together with a Gaussian emission feature at ∼6.55-6.7 keV modified by absorption due to cold and photoionised material. We found a significant correlation between the hard, ∼6-10 keV, flux, the ionisation and column density of the absorber and the equivalent width of the broad iron line. We interpret the correlation in a scenario in which a disc wind is thermally driven at large, ∼10 10 cm, radii and the broad line results from reprocessed emission in the wind and/or hot atmosphere. The breadth of the emission line is naturally explained by a combination of scattering, recombination and fluorescence processes. We attribute the variations in the absorption and emission along the orbital period to the view of different parts of the wind, possibly located at slightly different inclination angles. We constrain the inclination of GX 13+1 to be between 60 and 80 • from the strong absorption in the line of sight, which obscures up to 80% of the total emission in one observation, and the absence of eclipses. We conclude that either a disc wind and/or a hot atmosphere can explain the current observations of narrow absorption and broad iron emission features in neutron star low-mass X-ray binaries as a class.

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Discovery of X-ray absorption features from the dipping low-mass X-ray binary XB 1916-053 with XMM-Newton

Cited by 60 publications

References 46 publications

A systematic analysis of the broad iron Kαline in neutron-star LMXBs withXMM-Newton

A systematic analysis of the broad iron Kαline in neutron-star LMXBs withXMM-Newton

Disk emission and atmospheric absorption lines in black hole candidate 4U 1630-472

XMM-Newtonobservations of GX 13 + 1: correlation between photoionised absorption and broad line emission

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