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arxiv: 2607.00226 · v1 · pith:HHFGNU3Gnew · submitted 2026-06-30 · 🌌 astro-ph.HE

Dense, multi-phase accretion disk atmosphere in the low-luminosity state of black hole transientV4641 Sgr

Zuobin Zhang , Rob Fender , James H. Matthews , Jiachen Jiang , Honghui Liu , Alessandra Ambrifi , Teo Mu\~noz-Darias , Maxime Parra
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Megumi Shidatsu Menglei Zhou Yuexin Zhang Abdurakhmon Nosirov Cosimo Bambi Justine Crook-Mansour
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Pith reviewed 2026-07-02 17:19 UTC · model grok-4.3

classification 🌌 astro-ph.HE
keywords V4641 Sgrblack hole X-ray binaryaccretion disk atmospherephotoionization modelingX-ray spectroscopynarrow emission linesmultiphase plasma
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The pith

V4641 Sgr shows a radially extended multiphase dense disk atmosphere in its low-luminosity state.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper presents XMM-Newton RGS spectroscopy of the black hole X-ray binary V4641 Sgr in a low-luminosity state. Narrow emission lines from nitrogen and oxygen ions appear on a partially covered disk blackbody continuum. Blind line searches and photoionization modeling with two xstar components indicate dense plasma at intermediate and low ionization parameters. He-like triplet ratios support the dense plasma diagnosis, and small redshifted velocities are consistent with slowly moving gas. The findings imply a radially extended multiphase disk atmosphere that distinguishes this source from other X-ray binaries with similar lines.

Core claim

The RGS spectrum shows narrow emission features from N VI-VII and O VII-VIII that require two xstar photoionization components with log ξ ≃ 3.1 and log ξ ≃ 0.36, together with high G and low R ratios in the He-like triplets, establishing the presence of a dense, radially extended, multiphase disk atmosphere.

What carries the argument

Two xstar photoionization components fitted to the narrow N and O emission lines, with supporting He-like triplet diagnostics, that capture the ionization states and densities of the plasma.

If this is right

  • The atmosphere contains gas at both intermediate (log ξ ≃ 3.1) and low (log ξ ≃ 0.36) ionization states simultaneously.
  • Velocities of 540–720 km s^{-1} indicate quasi-static or slowly outflowing material after accounting for systematics.
  • An additional highly ionized component is suggested by Fe emission structures in the EPIC-pn spectrum.
  • The source shares high inclination with other binaries but is set apart by the presence of low-ionization emission lines.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Similar low-luminosity states in other black-hole binaries may contain undetected multiphase atmospheres if observed at comparable sensitivity.
  • The radial extent could be tested by searching for changes in line properties with luminosity or inclination in monitoring campaigns.
  • The distinction from other sources suggests that factors beyond inclination influence the visibility of low-ionization lines.

Load-bearing premise

The observed narrow lines arise from a photoionized disk atmosphere whose properties are captured by the two xstar components rather than from other locations or different physical processes.

What would settle it

If the narrow lines cannot be reproduced by the two xstar components or show velocities and ionization parameters inconsistent with the reported fits when observed at higher signal-to-noise, the disk atmosphere interpretation would be ruled out.

Figures

Figures reproduced from arXiv: 2607.00226 by Abdurakhmon Nosirov, Alessandra Ambrifi, Cosimo Bambi, Honghui Liu, James H. Matthews, Jiachen Jiang, Justine Crook-Mansour, Maxime Parra, Megumi Shidatsu, Menglei Zhou, Rob Fender, Teo Mu\~noz-Darias, Yuexin Zhang, Zuobin Zhang.

Figure 1
Figure 1. Figure 1: MAXI light curves of V4641 Sgr in the 2–4 keV (top) and 4–10 keV (bottom) energy bands through the on-demand system (Matsuoka et al. 2009), showing three recent outbursts. Vertical lines indicate the epochs of high-resolution X-ray observations. Green lines mark the XMM-Newton observations, red lines mark the Chandra observations, and the blue line marks the XRISM observation. This work focuses on the seco… view at source ↗
Figure 2
Figure 2. Figure 2: Top: EPIC-pn spectrum (black) with the best-fit continuum overlaid (red dashed). Bottom: data-to-model ratio of the fit with the continuum model Tbabs*pcfabs*diskbb. The 6.5–7.5 keV energy range was excluded when fitting the continuum model, but is included in the plotted spectrum and model for completeness. The O viii and N vii Ly𝛼 features are H-like Ly𝛼 transitions, which are fine-structure doublets con… view at source ↗
Figure 3
Figure 3. Figure 3: Upper panel: the RGS spectrum of V4641 Sgr in the 6–31 Å range, shown in units of 𝜈𝐹𝜈 (ergs cm−2 s −1 ). The data are shown in black with 1𝜎 error bars, and the best-fit continuum model is overplotted as a red dashed line. Several strong emission lines are evident, including those from highly ionized N and O. The vertical green ticks mark the expected positions of known transitions, including O viii Ly𝛼, O… view at source ↗
Figure 4
Figure 4. Figure 4: RGS spectrum of V4641 Sgr unfolded to best-fit model (Gaussian components plus the continuum). Each panel shows a region of the spectrum containing a likely line; the most probable transition, along with its rest wavelength, is indicated. The black histogram with grey error bars represents the observed spectrum, while the red dashed lines indicate the best-fit continuum plus Gaussian models [PITH_FULL_IMA… view at source ↗
Figure 5
Figure 5. Figure 5: RGS spectrum and photoionized emission modelling. Top: observed spectrum (black) with the best-fit continuum+emission model overlaid (red). Vertical green ticks mark the rest wavelengths of prominent H- and He-like transitions. Bottom: spectra from two photoionized components (in photos cm−2 s −1 Å −1 ), illustrating the transitions that dominate two XSTAR components [PITH_FULL_IMAGE:figures/full_fig_p007… view at source ↗
Figure 6
Figure 6. Figure 6: Residuals of EPIC-pn spectum to the best-fit RGS model with fixed parameters for the two XSTAR components. Strong excesses around 7.0 keV are clearly shown. the emission originates in a failed disk wind region high up in the disk atmosphere, where the emitting material is located at larger cylindrical radii. In this case, the rotational velocities are reduced as a consequence of angular momentum conservati… view at source ↗
read the original abstract

We present soft X-ray spectroscopy of the black-hole X-ray binary V4641~Sgr with the \textit{XMM-Newton} Reflection Grating Spectrometer (RGS). The RGS spectrum shows narrow emission features from N\,\textsc{vi--vii} and O\,\textsc{vii--viii} superimposed on a partially covered disk blackbody continuum. A blind Gaussian search confirms the presence of significant lines at the expected rest wavelengths. He-like triplet ratios (high $G$, low $R$) and full photoionization modelling both indicate a dense, photoionized plasma. Small redshifted velocities of $\sim 540$--$720\ \mathrm{km\ s^{-1}}$ are suggested, which are consistent with quasi-static or slowly flowing gas away from the observer after accounting for systematics. Photoionization modelling requires two \textsc{xstar} components with an intermediate ionization parameter ($\log\xi \simeq 3.1$) and a low ionization parameter ($\log\xi \simeq 0.36$), respectively. The simultaneous EPIC-pn spectrum suggests highly ionized Fe emission structures, hinting at an additional, more highly ionized component. These results imply the existence of a radially extended, multiphase, and dense disk atmosphere in the source. We compare the source with other X-ray binaries showing similar emission lines. V4641~Sgr shares a similarly high inclination with other sources; however, the presence of low ionization emission lines distinguishes it from the rest.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The manuscript presents soft X-ray spectroscopy of the black-hole X-ray binary V4641 Sgr using XMM-Newton RGS data in the low-luminosity state. Narrow emission lines from N VI-VII and O VII-VIII are identified via blind Gaussian search on a partially covered disk blackbody continuum. He-like triplet ratios and two-component xstar photoionization modeling (log ξ ≈ 3.1 and 0.36) indicate dense photoionized plasma, with small redshifted velocities (540–720 km s⁻¹) interpreted as consistent with quasi-static gas. The results are taken to imply a radially extended, multiphase, dense disk atmosphere, with comparison to other high-inclination X-ray binaries.

Significance. If the two xstar components correctly capture the plasma properties and the lines are shown to originate from a radially extended disk atmosphere (rather than alternative sites), the work would add to the evidence for complex atmospheric structures in black-hole transients, highlighting the role of low-ionization lines in distinguishing sources at similar inclinations.

major comments (2)
  1. [Abstract] Abstract: the reported velocities of 540–720 km s⁻¹ lack error bars, and the text provides no explicit tests of alternative models (e.g., single-component xstar or wind emission) nor discussion of line blending or continuum choices that could affect the ionization parameters and the radial-extension inference.
  2. [Photoionization modelling] Photoionization modelling: the central claim of a radially extended multiphase atmosphere rests on mapping the two xstar components (log ξ ≃ 3.1 and 0.36) via the ξ ∝ 1/(n r²) scaling without quantitative exclusion of alternative emission sites or velocity systematics; no falsification tests against single-component models or partial-covering effects are described.
minor comments (2)
  1. The simultaneous EPIC-pn spectrum is invoked to suggest highly ionized Fe structures but no quantitative details or fit parameters are supplied.
  2. The comparison paragraph with other X-ray binaries notes shared high inclination but does not quantify how the low-ionization lines distinguish V4641 Sgr beyond a qualitative statement.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their thorough review and constructive feedback on our manuscript. We address each major comment below and will revise the paper accordingly to strengthen the presentation of our results.

read point-by-point responses

  1. Referee: [Abstract] Abstract: the reported velocities of 540–720 km s⁻¹ lack error bars, and the text provides no explicit tests of alternative models (e.g., single-component xstar or wind emission) nor discussion of line blending or continuum choices that could affect the ionization parameters and the radial-extension inference.

    Authors: We agree that the velocities reported in the abstract lack error bars. In the revised manuscript we will quote the 1σ uncertainties derived from the Gaussian line centroid fits. We will also add explicit model comparison tests (including single-component xstar fits and a simple wind-emission scenario) together with a short discussion of possible line blending and the sensitivity of the derived log ξ values to continuum parameterization. These additions will be placed in a new subsection of the modeling section and referenced from the abstract. revision: yes

  2. Referee: [Photoionization modelling] Photoionization modelling: the central claim of a radially extended multiphase atmosphere rests on mapping the two xstar components (log ξ ≃ 3.1 and 0.36) via the ξ ∝ 1/(n r²) scaling without quantitative exclusion of alternative emission sites or velocity systematics; no falsification tests against single-component models or partial-covering effects are described.

    Authors: The manuscript already states that two xstar components are required to reproduce both the high- and low-ionization lines. In revision we will add quantitative falsification tests: (i) Δχ² and BIC values comparing the single- versus two-component models on the RGS data, and (ii) a brief exploration of how partial-covering fractions and velocity shifts affect the best-fit log ξ. We will also discuss why a radially extended disk atmosphere is favored over a compact wind given the small observed velocities and the source inclination. While a complete exclusion of every conceivable emission site is limited by the existing data quality, the added tests will make the supporting evidence for the multiphase atmosphere explicit. revision: yes

Circularity Check

0 steps flagged

No significant circularity; derivation is data-driven spectral fitting

full rationale

The paper derives its central claim (radially extended multiphase disk atmosphere) directly from fitting two xstar photoionization components plus a disk blackbody to the observed RGS emission lines in public XMM-Newton data. Ionization parameters (log ξ ≈ 3.1 and 0.36), densities from triplet ratios, and velocities are outputs of the fit rather than inputs; the radial-extension inference follows from the requirement for multiple ξ values under the standard ξ ∝ 1/(n r²) scaling. No self-citation chain, uniqueness theorem, or ansatz is invoked to justify the model choice, and no fitted parameter is relabeled as a prediction. The analysis remains self-contained against the spectrum itself.

Axiom & Free-Parameter Ledger

2 free parameters · 2 axioms · 0 invented entities

The claim rests on standard X-ray binary spectroscopy assumptions plus two fitted ionization parameters; no new entities are postulated.

free parameters (2)
  • log ξ (high)
    Fitted ionization parameter ≈3.1 for one xstar component; required to match the observed line ratios.
  • log ξ (low)
    Fitted ionization parameter ≈0.36 for the second xstar component; required to produce the low-ionization lines.
axioms (2)
  • domain assumption The narrow lines are produced by photoionized plasma whose emission can be modeled by the xstar code under the assumed density and illuminating spectrum.
    Invoked when the abstract states that full photoionization modelling indicates dense plasma.
  • domain assumption The continuum is a partially covered disk blackbody whose parameters can be jointly fit with the line components.
    Stated in the abstract description of the spectrum.

pith-pipeline@v0.9.1-grok · 5867 in / 1421 out tokens · 21950 ms · 2026-07-02T17:19:01.106017+00:00 · methodology

discussion (0)

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Reference graph

Works this paper leans on

88 extracted references · 79 canonical work pages · 39 internal anchors

  1. [1]

    , keywords =

    A highly ionised outflow in the X-ray binary 4U 1624─49 detected with XRISM. , keywords =. doi:10.1051/0004-6361/202558352 , archivePrefix =. 2601.19480 , primaryClass =

    work page doi:10.1051/0004-6361/202558352

  2. [2]

    , year = 1969, month = jun, volume =

    The Interaction of X-Ray Sources with Optically Thin Environments. , year = 1969, month = jun, volume =. doi:10.1086/150026 , adsurl =

    work page doi:10.1086/150026 1969

  3. [3]

    Accretion Power in Astrophysics: Third Edition

  4. [4]

    The Impact of Accretion Disk Winds on the Optical Spectra of Cataclysmic Variables

    The impact of accretion disc winds on the optical spectra of cataclysmic variables. , keywords =. doi:10.1093/mnras/stv867 , archivePrefix =. 1504.05590 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/stv867

  5. [5]

    Thermal Winds in Stellar Mass Black Hole and Neutron Star Binary Systems

    Thermal winds in stellar mass black hole and neutron star binary systems. , keywords =. doi:10.1093/mnras/stx2400 , archivePrefix =. 1612.09377 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/stx2400

  6. [6]

    , keywords =

    X-Ray--heated Coronae and Winds from Accretion Disks: Time-dependent Two-dimensional Hydrodynamics with Adaptive Mesh Refinement. , keywords =. doi:10.1086/177101 , adsurl =

    work page doi:10.1086/177101

  7. [7]

    , keywords =

    Simultaneous X-Ray and Optical Observations of GX 339-4 in an X-Ray High State. , keywords =. doi:10.1086/164534 , adsurl =

    work page doi:10.1086/164534

  8. [8]

    Broad-band gamma-ray and X-ray spectra of NGC 4151 and their implications for physical processes and geometry

    Broad-band -ray and X-ray spectra of NGC 4151 and their implications for physical processes and geometry. , keywords =. doi:10.1093/mnras/283.1.193 , archivePrefix =. astro-ph/9607015 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/283.1.193

  9. [9]

    , keywords =

    Evidence for a Black Hole in the X-Ray Transient GRS 1009-45. , keywords =. doi:10.1093/pasj/50.6.667 , adsurl =

    work page doi:10.1093/pasj/50.6.667

  10. [10]

    The low-luminosity accretion disc wind of the black hole transient V4641 Sagittarii

    The low-luminosity accretion disc wind of the black hole transient V4641 Sagittarii. , keywords =. doi:10.1093/mnras/sty1711 , archivePrefix =. 1806.10881 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/sty1711

  11. [11]

    The MAXI Mission on the ISS: Science and Instruments for Monitoring All Sky X-Ray Images

    The MAXI Mission on the ISS: Science and Instruments for Monitoring All-Sky X-Ray Images. , keywords =. doi:10.1093/pasj/61.5.999 , archivePrefix =. 0906.0631 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/pasj/61.5.999

  12. [12]

    , keywords =

    Probing the near-horizon region of Cygnus X-1 with S u z a k u and N u S T A R. , keywords =. doi:10.1103/PhysRevD.103.024055 , archivePrefix =. 2012.01112 , primaryClass =

    work page doi:10.1103/physrevd.103.024055 2012

  13. [13]

    Accretion disc winds in X-ray binaries

    Accretion disc winds in X-ray binaries. arXiv e-prints , keywords =. doi:10.48550/arXiv.2601.05319 , archivePrefix =. 2601.05319 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.2601.05319

  14. [14]

    , keywords =

    XRISM Spectroscopy of the Stellar-mass Black Hole 4U 1630-472 in Outburst. , keywords =. doi:10.3847/2041-8213/ade25c , archivePrefix =. 2506.07319 , primaryClass =

    work page doi:10.3847/2041-8213/ade25c 2041

  15. [15]

    , keywords =

    First look at Vela X-1 with XRISM: A simultaneous campaign with XMM-Newton and NuSTAR. , keywords =. doi:10.1051/0004-6361/202556244 , archivePrefix =. 2509.07258 , primaryClass =

    work page doi:10.1051/0004-6361/202556244

  16. [16]

    , keywords =

    The Disk Wind in GRS 1915+105 as Seen by Insight-Hard X-Ray Modulation Telescope. , keywords =. doi:10.3847/1538-4357/ac74b1 , archivePrefix =. 2203.02659 , primaryClass =

    work page doi:10.3847/1538-4357/ac74b1 1915

  17. [17]

    , keywords =

    Testing the Kerr Black Hole Hypothesis with GRS 1716-249 by Combining the Continuum Fitting and the Iron-line Methods. , keywords =. doi:10.3847/1538-4357/ac350e , archivePrefix =. 2106.03086 , primaryClass =

    work page doi:10.3847/1538-4357/ac350e

  18. [18]

    , keywords =

    Variable Ionized Disk Winds in MAXI J1803 - 298 Revealed by NICER. , keywords =. doi:10.3847/1538-4357/ad7b29 , archivePrefix =. 2402.10315 , primaryClass =

    work page doi:10.3847/1538-4357/ad7b29

  19. [19]

    , keywords =

    Large-scale radio bubbles around the black hole transient V4641 Sgr. , keywords =. doi:10.1051/0004-6361/202557124 , archivePrefix =. 2601.03140 , primaryClass =

    work page doi:10.1051/0004-6361/202557124

  20. [20]

    Nature Astronomy , year = 2026, month = feb, volume =

    Evidence of mutually exclusive outflow forms from a black hole X-ray binary. Nature Astronomy , year = 2026, month = feb, volume =. doi:10.1038/s41550-025-02753-x , adsurl =

    work page doi:10.1038/s41550-025-02753-x 2026

  21. [21]

    Modelling the behaviour of accretion flows in X-ray binaries

    Modelling the behaviour of accretion flows in X-ray binaries. Everything you always wanted to know about accretion but were afraid to ask. , keywords =. doi:10.1007/s00159-007-0006-1 , archivePrefix =. 0708.0148 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1007/s00159-007-0006-1

  22. [22]

    , keywords =

    Accretion states and radio loudness in active galactic nuclei: analogies with X-ray binaries. , keywords =. doi:10.1111/j.1365-2966.2006.10954.x , archivePrefix =. astro-ph/0608628 , primaryClass =

    work page doi:10.1111/j.1365-2966.2006.10954.x 2006

  23. [23]

    Broadband reflection spectroscopy of MAXI J1535-571 using AstroSat: Estimation of black hole mass and spin

    X-Ray Properties of Black-Hole Binaries. , keywords =. doi:10.1146/annurev.astro.44.051905.092532 , archivePrefix =. astro-ph/0606352 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1146/annurev.astro.44.051905.092532

  24. [24]

    , keywords =

    Hard X-ray spectrum of CYG X-1. , keywords =. doi:10.1038/279506a0 , adsurl =

    work page doi:10.1038/279506a0

  25. [25]

    Black Holes (Les Astres Occlus) , year = 1973, editor =

    Astrophysics of black holes. Black Holes (Les Astres Occlus) , year = 1973, editor =

    1973

  26. [26]

    Observational appearance

    Black holes in binary systems. Observational appearance. , year = 1973, month = jan, volume =

    1973

  27. [27]

    The Structure and X-ray Recombination Emission of a Centrally Illuminated Accretion Disk Atmosphere and Corona

    The Structure and X-Ray Recombination Emission of a Centrally Illuminated Accretion Disk Atmosphere and Corona. , keywords =. doi:10.1086/344364 , archivePrefix =. astro-ph/0208488 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/344364

  28. [28]

    , keywords =

    On the Spectral Hardening Factor of the X-Ray Emission from Accretion Disks in Black Hole Candidates. , keywords =. doi:10.1086/175740 , adsurl =

    work page doi:10.1086/175740

  29. [29]

    Vertical Structure of Gas Pressure-Dominated Accretion Disks with Local Dissipation of Turbulence and Radiative Transport

    Vertical Structure of Gas Pressure-dominated Accretion Disks with Local Dissipation of Turbulence and Radiative Transport. , keywords =. doi:10.1086/499153 , archivePrefix =. astro-ph/0510741 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/499153

  30. [30]

    , archivePrefix = "arXiv", eprint =

    Ubiquitous equatorial accretion disc winds in black hole soft states. , keywords =. doi:10.1111/j.1745-3933.2012.01224.x , archivePrefix =. 1201.4172 , primaryClass =

    work page doi:10.1111/j.1745-3933.2012.01224.x 2012

  31. [31]

    Lecture Notes in Physics, Berlin Springer Verlag , year = 2016, editor =

    The Balance of Power: Accretion and Feedback in Stellar Mass Black Holes. Lecture Notes in Physics, Berlin Springer Verlag , year = 2016, editor =. doi:10.1007/978-3-319-19416-5_3 , adsurl =

    work page doi:10.1007/978-3-319-19416-5_3 2016

  32. [32]

    Compton heated winds and coronae above accretion disks. I. Dynamics. , keywords =. doi:10.1086/161178 , adsurl =

    work page doi:10.1086/161178

  33. [33]

    The Chandra HETGS and RXTE view of GRS 1915+105

    High-Resolution Chandra HETGS and Rossi X-Ray Timing Explorer Observations of GRS 1915+105: A Hot Disk Atmosphere and Cold Gas Enriched in Iron and Silicon. , keywords =. doi:10.1086/338588 , archivePrefix =. astro-ph/0208187 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/338588 1915

  34. [34]

    The Accretion Disk Wind in the Black Hole GRS 1915+105

    The Accretion Disk Wind in the Black Hole GRS 1915+105. , keywords =. doi:10.3847/2041-8205/821/1/L9 , archivePrefix =. 1603.01474 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/2041-8205/821/1/l9 1915

  35. [35]

    GRS 1915+105 in "Soft State": Nature of Accretion Disk Wind and Origin of X-Ray Emission

    GRS 1915+105 in ``Soft State'': Nature of Accretion Disk Wind and Origin of X-ray Emission. , keywords =. doi:10.1088/0004-637X/695/2/888 , archivePrefix =. 0901.1982 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/695/2/888 1915

  36. [36]

    Accretion disc atmospheres and winds in low-mass X-ray binaries

    Accretion disc atmospheres and winds in low-mass X-ray binaries. Astronomische Nachrichten , keywords =. doi:10.1002/asna.201612315 , archivePrefix =. 1510.03576 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1002/asna.201612315

  37. [37]

    Modelling the disk atmosphere of the low mass X-ray binary EXO 0748-676

    Modelling the disc atmosphere of the low mass X-ray binary EXO 0748-676. , keywords =. doi:10.1051/0004-6361/201834000 , archivePrefix =. 1809.06864 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361/201834000

  38. [38]

    , keywords =

    Soft X-ray emission lines in the X-ray binary Swift J1858.6-0814 observed with XMM-Newton Reflection Grating Spectrometer: disc atmosphere or wind?. , keywords =. doi:10.1093/mnras/staa2258 , archivePrefix =. 2007.14407 , primaryClass =

    work page doi:10.1093/mnras/staa2258 2007

  39. [39]

    , keywords =

    A Redshifted Inner Disk Atmosphere and Transient Absorbers in the Ultracompact Neutron Star X-Ray Binary 4U 1916-053. , keywords =. doi:10.3847/2041-8213/aba9de , archivePrefix =. 2008.01083 , primaryClass =

    work page doi:10.3847/2041-8213/aba9de 1916

  40. [40]

    Evolution of the disc atmosphere in the X-ray binary MXB 1659-298, during its 2015-2017 outburst

    Evolution of the disc atmosphere in the X-ray binary MXB 1659-298, during its 2015-17 outburst. , keywords =. doi:10.1093/mnras/stz1245 , archivePrefix =. 1905.01308 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/stz1245 2015

  41. [41]

    High Resolution Chandra HETG spectroscopy of V404 Cygni in Outburst

    High-resolution Chandra HETG Spectroscopy of V404 Cygni in Outburst. , keywords =. doi:10.1088/2041-8205/813/2/L37 , archivePrefix =. 1508.01181 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/2041-8205/813/2/l37 2041

  42. [42]

    Spectrum Synthesis Modeling of the X-ray Spectrum of GRO J1655-40 Taken During the 2005 Outburst

    Spectrum Synthesis Modeling of the X-Ray Spectrum of GRO J1655-40 Taken During the 2005 Outburst. , keywords =. doi:10.1088/0004-637X/701/2/865 , archivePrefix =. 0905.4206 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/701/2/865 2005

  43. [43]

    A Black Hole in the Superluminal source SAX J1819.3-2525 (V4641 Sgr)

    A Black Hole in the Superluminal Source SAX J1819.3-2525 (V4641 Sgr). , keywords =. doi:10.1086/321442 , archivePrefix =. astro-ph/0103045 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/321442

  44. [44]

    The Black Hole Binary V4641 Sagitarii: Activity in Quiescence & Improved Mass Determinations

    The Black Hole Binary V4641 Sagitarii: Activity in Quiescence and Improved Mass Determinations. , keywords =. doi:10.1088/0004-637X/784/1/2 , archivePrefix =. 1401.4190 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/784/1/2

  45. [45]

    Super-Eddington outburst of V4641 Sgr

    Super-Eddington outburst of V4641 Sgr. , keywords =. doi:10.1051/0004-6361:20020865 , archivePrefix =. astro-ph/0204132 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361:20020865

  46. [46]

    , keywords =

    Light Curves and Radio Structure of the 1999 September Transient Event in V4641 Sagittarii (=XTE J1819-254=SAX J1819.3-2525). , keywords =. doi:10.1086/317255 , adsurl =

    work page doi:10.1086/317255 1999

  47. [47]

    The Astronomer's Telegram , keywords =

    Swift/XRT suggests a faint soft state in the 2015 outburst of V4641 Sgr. The Astronomer's Telegram , keywords =

    2015

  48. [48]

    , keywords =

    High resolution X-ray spectroscopy of V4641 Sgr during its 2020 outburst. , keywords =. doi:10.1093/mnras/stac2213 , archivePrefix =. 2208.01732 , primaryClass =

    work page doi:10.1093/mnras/stac2213 2020

  49. [49]

    XRISM reveals a variable, multi-phase outflow-inflow structure during the X-ray obscured 2024 outburst of the black hole transient V4641 Sgr

    XRISM reveals a variable, multi-phase outflow-inflow structure during the X-ray obscured 2024 outburst of the black hole transient V4641 Sgr. arXiv e-prints , keywords =. doi:10.48550/arXiv.2508.17541 , archivePrefix =. 2508.17541 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.2508.17541 2024

  50. [50]

    High ionisation absorption in low mass X-ray binaries

    High ionisation absorption in low mass X-ray binaries. Astronomische Nachrichten , keywords =. doi:10.1002/asna.201612339 , archivePrefix =. 1510.08902 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1002/asna.201612339

  51. [51]

    The Astronomer's Telegram , keywords =

    MAXI/GSC detection of renewed activity of the black hole X-ray binary V4641 Sgr. The Astronomer's Telegram , keywords =

  52. [52]

    , keywords =

    The Reflection Grating Spectrometer on board XMM-Newton. , keywords =. doi:10.1051/0004-6361:20000058 , adsurl =

    work page doi:10.1051/0004-6361:20000058

  53. [53]

    Astronomical Data Analysis Software and Systems V , year = 1996, editor =

    XSPEC: The First Ten Years. Astronomical Data Analysis Software and Systems V , year = 1996, editor =

    1996

  54. [54]

    On the Absorption of X-rays in the Interstellar Medium

    On the Absorption of X-Rays in the Interstellar Medium. , keywords =. doi:10.1086/317016 , archivePrefix =. astro-ph/0008425 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/317016

  55. [55]

    Atomic Data for Astrophysics. II. New Analytic Fits for Photoionization Cross Sections of Atoms and Ions. , keywords =. doi:10.1086/177435 , archivePrefix =. astro-ph/9601009 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/177435

  56. [56]

    , keywords =

    Parameter estimation in astronomy through application of the likelihood ratio. , keywords =. doi:10.1086/156922 , adsurl =

    work page doi:10.1086/156922

  57. [57]

    , keywords =

    Energy spectra of low-mass binary X-ray sources observed from Tenma. , keywords =

  58. [58]

    , keywords =

    Photoionization and High-Density Gas. , keywords =. doi:10.1086/319184 , adsurl =

    work page doi:10.1086/319184

  59. [59]

    Updated Atomic Data and Calculations for X-ray Spectroscopy

    Updated Atomic Data and Calculations for X-Ray Spectroscopy. , keywords =. doi:10.1088/0004-637X/756/2/128 , archivePrefix =. 1207.0576 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/756/2/128

  60. [60]

    Statistics: Handle with Care, Detecting Multiple Model Components with the Likelihood Ratio Test

    Statistics, Handle with Care: Detecting Multiple Model Components with the Likelihood Ratio Test. , keywords =. doi:10.1086/339856 , archivePrefix =. astro-ph/0201547 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/339856

  61. [61]

    X-ray photoionized plasma diagnostics with Helium-like ions. Application to Warm Absorber-Emitter in Active Galactic Nuclei

    X-ray photoionized plasma diagnostics with helium-like ions. Application to warm absorber-emitter in active galactic nuclei. , keywords =. doi:10.1051/aas:2000192 , archivePrefix =. astro-ph/0002319 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/aas:2000192

  62. [62]

    X-Ray Spectroscopy in Astrophysics , year = 1999, editor =

    The X-Ray Spectral Properties of Photoionized Plasma and Transient Plasmas. X-Ray Spectroscopy in Astrophysics , year = 1999, editor =. doi:10.1007/978-3-540-49199-6_3 , adsurl =

    work page doi:10.1007/978-3-540-49199-6_3 1999

  63. [63]

    Helium-like ion line intensities. I. Stationary plasmas. , keywords =

  64. [64]

    Philosophical Transactions of the Royal Society of London Series A , year = 2002, month = sep, volume =

    X-ray spectroscopy of astrophysical plasmas. Philosophical Transactions of the Royal Society of London Series A , year = 2002, month = sep, volume =. doi:10.1098/rsta.2002.1043 , adsurl =

    work page doi:10.1098/rsta.2002.1043 2002

  65. [65]

    , archivePrefix = "arXiv", eprint =

    Improving the full spectrum fitting method: accurate convolution with Gauss-Hermite functions. , keywords =. doi:10.1093/mnras/stw3020 , archivePrefix =. 1607.08538 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/stw3020

  66. [66]

    , keywords =

    Reprocessing from Highly Ionized Gas in the Soft Spectral State of V4641 Sgr with NuSTAR. , keywords =. doi:10.3847/1538-4357/adbbdb , archivePrefix =. 2503.07835 , primaryClass =

    work page doi:10.3847/1538-4357/adbbdb

  67. [67]

    He-like ions as practical astrophysical plasma diagnostics: From stellar coronae to active galactic nuclei

    He-like Ions as Practical Astrophysical Plasma Diagnostics: From Stellar Coronae to Active Galactic Nuclei. , keywords =. doi:10.1007/s11214-010-9731-2 , archivePrefix =. 1101.3184 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1007/s11214-010-9731-2

  68. [68]

    , keywords =

    Detection of Extended X-Ray Emission around the PeVatron Microquasar V4641 Sgr with XRISM. , keywords =. doi:10.3847/2041-8213/ad9d11 , archivePrefix =. 2412.08089 , primaryClass =

    work page doi:10.3847/2041-8213/ad9d11 2041

  69. [69]

    , keywords =

    Ultra-high-energy gamma-ray bubble around microquasar V4641 Sgr. , keywords =. doi:10.1038/s41586-024-07995-9 , archivePrefix =. 2410.16117 , primaryClass =

    work page doi:10.1038/s41586-024-07995-9

  70. [70]

    arXiv e-prints , keywords =

    Ultrahigh-Energy Gamma-ray Emission Associated with Black Hole-Jet Systems. arXiv e-prints , keywords =. doi:10.48550/arXiv.2410.08988 , archivePrefix =. 2410.08988 , primaryClass =

    work page doi:10.48550/arxiv.2410.08988

  71. [71]

    Photoionization Modeling and the K Lines of Iron

    Photoionization Modeling and the K Lines of Iron. , keywords =. doi:10.1086/424039 , archivePrefix =. astro-ph/0405210 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/424039

  72. [72]

    Constraining distance and inclination angle of V4641 Sgr using ${\it SWIFT}$ and ${\it NuSTAR}$ observations during low soft spectral state

    Constraining Distance and Inclination Angle of V4641 Sgr Using Swift and NuSTAR Observations during Low Soft Spectral State. , keywords =. doi:10.1088/0004-637X/814/2/158 , archivePrefix =. 1510.07837 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/814/2/158

  73. [73]

    , keywords =

    Dips and eclipses in the X-ray binary Swift J1858.6-0814 observed with NICER. , keywords =. doi:10.1093/mnras/stab863 , archivePrefix =. 2103.12787 , primaryClass =

    work page doi:10.1093/mnras/stab863

  74. [74]

    , keywords =

    The Discovery of 3.8 Hour Periodic Intensity Dips and Eclipses from the Transient Low-Mass X-Ray Binary EXO 0748-676. , keywords =. doi:10.1086/164490 , adsurl =

    work page doi:10.1086/164490

  75. [75]

    Eclipse Timings of the Transient Low-Mass X-ray Binary EXO 0748-676. IV. The Rossi X-ray Timing Explorer Eclipses. , keywords =. doi:10.1088/0067-0049/183/1/156 , archivePrefix =. 0812.1034 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0067-0049/183/1/156

  76. [76]

    , keywords =

    Discovery of a 50 MN binary period and a likely 22 magnitude optical counterpart for the X-ray burster 4U 1915-05. , keywords =. doi:10.1086/183738 , adsurl =

    work page doi:10.1086/183738 1915

  77. [77]

    A possible solution of the puzzling variation of the orbital period of MXB 1659-298

    A possible solution of the puzzling variation of the orbital period of MXB 1659-298. , keywords =. doi:10.1093/mnras/stx2529 , archivePrefix =. 1703.05294 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/stx2529

  78. [78]

    1999 , month =

    MERLIN observations of relativistic ejections from GRS 1915+105. , keywords =. doi:10.1046/j.1365-8711.1999.02364.x , archivePrefix =. astro-ph/9812150 , primaryClass =

    work page doi:10.1046/j.1365-8711.1999.02364.x 1915

  79. [79]

    A Parallax Distance to the Microquasar GRS 1915+105 and a Revised Estimate of its Black Hole Mass

    A Parallax Distance to the Microquasar GRS 1915+105 and a Revised Estimate of its Black Hole Mass. , keywords =. doi:10.1088/0004-637X/796/1/2 , archivePrefix =. 1409.2453 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/796/1/2 1915

  80. [80]

    Optical studies of V404 Cyg, the X-ray transient GS 2023+338. IV. The rotation speed of the companion star. , keywords =. doi:10.1093/mnras/271.1.L5 , adsurl =

    work page doi:10.1093/mnras/271.1.l5 2023

Showing first 80 references.