Pith. sign in

REVIEW 4 major objections 4 minor 37 references

The role of XMM-Newton in the investigation of persistent BeXRBs

T0 review · 4 major / 4 minor · reviewed 2026-08-12 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗ Review JSON

Pith's one-line read Most persistent BeXRBs share a hot blackbody component that very likely comes from the neutron star's polar caps, a claim now supported by a coherent set of XMM-Newton observations.

desk verdict Useful synthesis of persistent BeXRBs; the polar-cap conclusion is plausible but not as secure as the abstract suggests. read the letter →

arxiv 2411.14966 v1 pith:YX5AIVOA submitted 2024-11-22 astro-ph.HE

N. La Palombara (1) , L. Sidoli (1) , S. Mereghetti (1) , G. L. Israel (2) , P. Esposito (3) (1) INAF - IASF Milano , (2) INAF - OA Roma , (3) IUSS Pavia This is my paper · ORCID
classification astro-ph.HE
keywords persistentBeX-raybinariesXMM-Newtonobservationsneutronstarpolarcaphotblackbodycomponentpulsarswindaccretionhigh-massphase-resolvedspectroscopy
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

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

The reading

This paper aims to establish that persistent Be X-ray binaries form a single class with a recognizable X-ray fingerprint, and that the fingerprint is best seen with XMM-Newton. Drawing on observations of 11 sources, it shows that most of them share a low pulsed fraction variation with energy, a hard power-law spectrum with no strong iron line, and a hot blackbody component with kT of about 1-2 keV that carries 20-40% of the total flux. The blackbody's emitting radius comes out around a few hundred meters, matching the expected footprint of the accretion column on a canonical neutron star. The paper concludes that this hot component very likely comes from the neutron star's polar caps, making it a common, physically meaningful signature of wind-fed accretion onto slowly spinning neutron stars.

What carries the argument

The central object is the hot blackbody component, characterized by its best-fit temperature kT_BB and emitting radius R_BB. To decide where it originates, the paper applies the standard magnetospheric accretion geometry: from the observed luminosity it computes the accretion rate, the magnetospheric radius R_m, and the accretion-column radius R_col approximately equal to R_NS times the square root of (R_NS/R_m), assuming M_NS = 1.4 solar masses, R_NS = $10^{6}$ cm, and B_NS = $10^{12}$ G. The agreement between R_BB and R_col to within a factor of about two is the quantitative argument that the blackbody is polar-cap emission.

What would settle it

Take one persistent BeXRB with a detected hot blackbody, measure its distance independently through a parallax and determine its surface magnetic field from a cyclotron absorption line, then recompute the accretion-column radius R_col using the paper's formulas. If R_col and R_BB no longer agree within roughly a factor of two, the polar-cap interpretation for that source fails.

Watch

Extended reading notes

Core claim

The central discovery is that persistent BeXRBs exhibit a hot blackbody spectral component that is common, not incidental: it appears in eight of the eleven sources listed, and in seven of those it was detected with XMM-Newton. Its parameters cluster tightly, with temperature kT of about 1-2 keV, radius R_BB less than about 1 km, and a fractional flux contribution of 20-40%, and they coincide with what is expected for the thermal mound at the base of the accretion column over a neutron-star polar cap. Two sources, Swift J045106.8-694803 and 4U 0728-25, show blackbody variability with pulse phase, which supports a compact hotspot that rotates into and out of the observer's line of sight. The paper also contrasts this hot-BB component with the soft excess seen in more luminous, shorter-period pulsars, placing persistent BeXRBs in a distinct low-luminosity, long-period regime of the luminosity-spin-period plane.

Load-bearing premise

The polar-cap conclusion depends on assuming a canonical neutron star with a mass of 1.4 solar masses, a radius of 10 km, and a surface magnetic field of $10^{12}$ gauss, and on the literature distances used to turn observed flux into luminosity; if those numbers are wrong for a given source, the blackbody radius and the predicted accretion-column radius would no longer line up.

Editorial extensions

If this is right

  • The hot blackbody component can serve as a classification criterion: a low-luminosity wind-fed pulsar with a roughly 1-2 keV blackbody and an emission radius below about 1 km is likely a persistent BeXRB, even before the orbit is fully characterized.
  • The roughly constant 20-40% contribution of the blackbody across sources and luminosity states implies a stable energy partition between the accretion column and the polar-cap hotspot, which any accretion model of these systems must reproduce.
  • Phase-resolved spectroscopy, which XMM-Newton made possible for these sources, can map the hotspot geometry; the two sources with a variable blackbody already show that hotspot visibility changes with pulse phase.
  • The luminosity-spin-period diagram separates persistent BeXRBs from soft-excess pulsars, sharpening the boundary between wind-fed and disk-fed accretion regimes.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • If the polar-cap identification holds, the measured blackbody radius becomes a probe of the accretion-column footprint, which depends on surface magnetic field and distance; combining R_BB with an independent distance for a few sources could effectively measure the magnetic field at the neutron star surface without waiting for cyclotron lines.
  • The clean separation in Fig. 2 between hot-BB and soft-excess pulsars suggests a physical transition between accretion regimes; targeted observations of intermediate-luminosity systems at L_X near 10^35-10^36 erg/s might catch both components simultaneously and reveal how the two emission mechanisms interchange.
  • The sample is still small, so the claim of near-ubiquity is testable: observing the remaining persistent BeXRBs without a detected hot blackbody with the same depth as XMM-Newton would either consolidate the class or reveal a subpopulation with a different accretion geometry.
Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

4 major / 4 minor

Summary. This review paper compiles XMM-Newton and other telescope observations of persistent Be X-ray binaries (BeXRBs), presenting a table of 15 observations of 11 sources and arguing that the class shares common properties: long spin periods, hard power-law spectra, a hot blackbody (BB) component with kT = 1–2 keV contributing 20–40% of the flux, and a small emitting radius consistent with the neutron star polar cap. The paper also reports preliminary XMM-Newton results for 4U 0728-25 and compares the measured BB radii with an expected accretion-column radius R_col derived from assumed neutron star parameters, concluding that the hot BB very likely originates at the polar caps.

Significance. If the central synthesis holds, the paper provides a useful observational framework for low-luminosity, long-period accreting pulsars and documents the key role of XMM-Newton in this field. The compilation in Table 1 is valuable as a reference, and the R_col comparison is a reasonable first-order consistency check that is not a fit to the measured BB radius. However, the polar-cap interpretation rests on assumed neutron star masses, radii, and magnetic fields, and the paper's abstract overstates the robustness of this conclusion. The inclusion of preliminary 4U 0728-25 results without full analysis details weakens the evidentiary basis for an eighth hot-BB source.

major comments (4)
  1. [Section 5, R_col comparison] The conclusion that the BB component 'very likely originates at the NS polar caps' is not supported by the R_BB–R_col comparison because the comparison is highly sensitive to assumed parameters. Specifically, R_col ∝ B^{-2/7} d^{2/7} (for fixed accretion efficiency), while R_BB ∝ d, so a factor of 10 in the assumed magnetic field changes R_col by about a factor of 1.5, and a factor-of-2 distance error changes the ratio R_BB/R_col by about 40%. Since no source-specific magnetic field measurements (e.g., cyclotron lines) are presented for the eight hot-BB sources, the stated agreement 'within a factor of about 2' does not uniquely discriminate polar-cap emission from other compact heated regions. The paper should either obtain or cite independent B-field estimates, or soften the conclusion to say the data are consistent with, but do not prove, polar-cap origin.
  2. [Abstract and Section 2, pulsed fraction claim] The abstract states that persistent BeXRBs share 'a pulsed fraction that does not vary with the photon energy,' but the body of the paper does not present any energy-resolved pulsed-fraction measurements or cite a specific figure or table showing this property. Table 1 lists only a single pulsed-fraction value per observation in the 2–10 keV band. As this is a central common-property claim, the paper should either add the supporting energy-dependent data or rephrase the abstract to match what is actually demonstrated.
  3. [Table 1 and Section 2, 4U 0728-25 results] The first XMM-Newton results for 4U 0728-25 are labeled 'preliminary' and referenced to 'La Palombara et al. 2025, in preparation,' yet they are included as a full row in Table 1 and as a data point in Figure 1. No details of the observation, data reduction, spectral extraction, or fit quality are given in the text. Because this source is one of the eight hot-BB sources that support the paper's central claim, the results should either be fully described (including uncertainties and fit parameters) or removed from the compilation until the dedicated paper is available.
  4. [Section 5, assumed parameters and error propagation] The R_col calculation assumes M_NS = 1.4 M_sun, R_NS = 10^6 cm, and B_NS = 10^12 G for all sources. The paper notes that uncertainties in these parameters affect the comparison, but it does not propagate them into the R_col values quoted in Table 1, and it does not discuss the systematic uncertainty from converting the 2–10 keV luminosity into the mass accretion rate used in the magnetospheric radius formula. A quantitative error budget for R_col, or at least a discussion of the range of R_col values allowed by plausible parameter ranges, is needed before a factor-of-2 agreement can be claimed as meaningful.
minor comments (4)
  1. [Throughout] The text contains several typographical errors, e.g., 'perfomed' in Section 1, 'XMM-Netwon' in Table 1 reference (6), and 'phased-resolved' should be 'phase-resolved' in Section 5.
  2. [Table 1] Many entries lack error bars, particularly for L_X, EW, and PF. For a compilation intended to support common-property claims, the table should state which values are upper limits and which are measurements without quoted uncertainties, or provide a note explaining the absence of errors.
  3. [Section 3, Figure 1] The figure caption lists references but does not state which symbol colors correspond to persistent versus transient sources; the text mentions red and blue symbols, but the caption should explicitly say this to avoid ambiguity.
  4. [Section 4, Figure 2] The diagram separates 'soft excess' and 'hot-BB' sources, but the distinction between the two groups is not quantified. Consider adding a sentence defining the temperature and radius criteria used for classification.

Circularity Check

0 steps flagged · score 0.0 of 10

No circularity found: the synthesis rests on independent XMM-Newton analyses, and the polar-cap check is a consistency estimate, not a fitted prediction.

full rationale

The paper is an observational review plus a preliminary new measurement for 4U 0728-25. Its main claims are: (1) persistent BeXRBs share common spectral and timing properties; (2) a hot blackbody component appears in most of them; (3) this component likely originates at the neutron-star polar caps. None of these claims is defined into existence. The hot-BB component is not part of the original Reig & Roche (1999) class definition, so finding it common is not a tautology. The R_BB values come from spectral fits to individual observations; the R_col values are computed from canonical NS parameters and measured luminosities using the standard magnetospheric-radius relations. The comparison in Section 5 is a parameter-free consistency check, not a fit to the target result, and no equation in the paper reduces R_BB to R_col by construction. The main caveat is that the R_BB-R_col agreement depends on assumed M_NS, R_NS, B_NS and distances, so the 'factor of about 2' agreement is not decisive; but parameter sensitivity is a correctness/robustness concern, not circularity. The self-citations (La Palombara & Mereghetti 2006, 2007; La Palombara et al. 2009, 2012, 2021) are prior independent data analyses of XMM-Newton observations, and they are used as evidence, not as the conclusion. The reference to La Palombara et al. (2025, in preparation) for 4U 0728-25 is unpublished and self-referential, and the paper labels the results preliminary; this weakens the evidential basis slightly but does not make the claim equivalent to an input. Overall, no significant circularity is present.

Assumptions & free parameters 4 free parameters · 3 assumptions · 0 invented entities

The paper introduces no new physical entities. Its interpretive claims rest on standard accretion theory, assumed neutron star parameters, and the assumption that the fitted spectral component is a blackbody.

free parameters (4)
  • Assumed neutron star mass M_NS = 1.4 solar masses
    Chosen by hand in Section 5 to compute R_col; not fitted, but affects the comparison.
  • Assumed neutron star radius R_NS = 1e6 cm
    Chosen by hand in Section 5; enters R_col and M_dot.
  • Assumed magnetic field B_NS = 1e12 G
    Chosen by hand in Section 5; strongly affects magnetospheric radius and R_col.
  • Source distances
    Distances for each source are taken from the literature (within 30% uncertainty) and affect both L_X and R_BB; not fitted in this paper.
assumptions (3)
  • domain assumption The bolometric luminosity is converted to an accretion rate via M_dot = L_X R_NS / (G M_NS).
    Assumes accretion luminosity is the dominant source of X-rays and all accretion power is radiated; used in Section 5.
  • domain assumption The magnetospheric radius is R_m = [mu^4 / (2 G M M_dot^2)]^(1/7) and the accretion column radius is R_col ~ R_NS (R_NS / R_m)^(1/2).
    Standard spherical accretion model; depends on the assumed geometry and magnetic field configuration.
  • domain assumption The thermal component seen in the spectra is a blackbody, and its fitted normalization gives an emitting area interpreted as the size of the polar cap.
    Assumes the soft excess is optically thick blackbody emission from the NS surface, not, e.g., cyclotron or other emission; used throughout the spectral interpretation.

how reviews work

0 comments
Cite this review

Pith. "Pith review of The role of XMM-Newton in the investigation of persistent BeXRBs." pith.science (2026). https://pith.science/paper/YX5AIVOA

@misc{pith2026241114966,
  author       = {Pith},
  title        = {Pith review of: The role of XMM-Newton in the investigation of persistent BeXRBs},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/YX5AIVOA}},
  note         = {Machine review of arXiv:2411.14966}
}
abstract

The persistent BeXRBs are a class of High-Mass X-ray Binaries (HMXRBs), which are characterized by persistent low X-ray luminosities ($L_{\rm X} \sim 10^{34}$ erg s$^{-1}$) and wide ($P_{\rm orb} >$ 30 d), almost circular orbits. In these sources the NS is slowly rotating (with $P_{\rm spin}$ well above 100 s) and accretes matter directly from the wind of the companion Be star, without the formation of an accretion disk. Since the '90s, when the first four members of this class were identified, several other sources of the same type have been discovered and investigated. Thanks to follow-up XMM-Newton observations, we have verified that most of them share common spectral and timing properties, such as a pulsed fraction that does not vary with the photon energy and a hot (kT = 1-2 keV) blackbody spectral component which contributes for 20-40 % to the total flux and has a size consistent with the NS polar cap. Here we provide an overview of how XMM-Newton contributed to constrain the observational properties and the current understanding of this type of sources. We also report about the first results obtained with a very recent XMM-Newton observation of the poorly known BeXRB 4U 0728-25.

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

37 extracted references · 22 canonical work pages

  1. [1]

    write newline

    " write newline " cite write " FUNCTION editor.postfix editor num.names #1 > "( )" "( )" if FUNCTION editor.trans.postfix editor num.names #1 > "( )" "( )" if FUNCTION trans.postfix translator num.names #1 > "( )" "( )" if FUNCTION authors.editors.reflist.apa5 'field := 'dot := field num.names 'numnames := numnames 'format.num.names := format.num.names na...

  2. [2]

    , Coe , M J

    Bartlett+13 APACrefauthors Bartlett , E S. , Coe , M J. \ Ho , W C G. APACrefauthors \ 2013 12 , 436 3 2054-2062 . APACrefDOI doi:10.1093/mnras/stt1711 APACrefDOI

    work page doi:10.1093/mnras/stt1711 2013

  3. [3]

    , Stella , L

    Bozzo+10 APACrefauthors Bozzo , E. , Stella , L. , Ferrigno , C. \ et al. APACrefauthors \ 2010 09 , 519 A6 . APACrefDOI doi:10.1051/0004-6361/201014095 APACrefDOI

    work page doi:10.1051/0004-6361/201014095 2010

  4. [4]

    , Heindl , W A

    Coburn+01 APACrefauthors Coburn , W. , Heindl , W A. , Gruber , D E. , Rothschild , R E. , Staubert , R. , Wilms , J. \ Kreykenbohm , I. APACrefauthors \ 2001 05 , 552 2 738-747 . APACrefDOI doi:10.1086/320565 APACrefDOI

    doi:10.1086/320565 2001

  5. [5]

    , Maccarone , M C

    Cusumano+00 APACrefauthors Cusumano , G. , Maccarone , M C. , Nicastro , L. , Sacco , B. \ Kaaret , P. APACrefauthors \ 2000 01 , 528 1 L25-L28 . APACrefDOI doi:10.1086/312413 APACrefDOI

    doi:10.1086/312413

  6. [6]

    , Patel , S K

    Gogus+05 APACrefauthors G \"o g \"u s , E. , Patel , S K. , Wilson , C A. , Woods , P M. , Finger , M H. \ Kouveliotou , C. APACrefauthors \ 2005 10 , 632 2 1069-1074 . APACrefDOI doi:10.1086/444373 APACrefDOI

    work page doi:10.1086/444373 2005

  7. [7]

    , Oskinova , L M

    Henault-Brunet+12 APACrefauthors H \'e nault-Brunet , V. , Oskinova , L M. , Guerrero , M A. \ et al. APACrefauthors \ 2012 02 , 420 1 L13-L17 . APACrefDOI doi:10.1111/j.1745-3933.2011.01183.x APACrefDOI

    arXiv 2012

  8. [8]

    , Narayan , R

    Hickox+04 APACrefauthors Hickox , R C. , Narayan , R. \ Kallman , T R. APACrefauthors \ 2004 10 , 614 2 881-896 . APACrefDOI doi:10.1086/423928 APACrefDOI

    doi:10.1086/423928 2004

Show all 37 references
  1. [9]

    , Baykal , A

    Inam+04 APACrefauthors \.I nam , S C . , Baykal , A. , Swank , J. \ Stark , M J. APACrefauthors \ 2004 11 , 616 1 463-468 . APACrefDOI doi:10.1086/424825 APACrefDOI

    2004 doi

  2. [10]

    , Lumb , D

    Jansen+01 APACrefauthors Jansen , F. , Lumb , D. , Altieri , B. \ et al. APACrefauthors \ 2001 01 , 365 L1-L6 . APACrefDOI doi:10.1051/0004-6361:20000036 APACrefDOI

    2001 doi

  3. [11]

    , Burderi , L

    LaBarbera+01 APACrefauthors La Barbera , A. , Burderi , L. , Di Salvo , T. , Iaria , R. \ Robba , N R. APACrefauthors \ 2001 05 , 553 1 375-381 . APACrefDOI doi:10.1086/320643 APACrefDOI

    2001 doi

  4. [12]

    , Esposito , P

    LaPalombara+18 APACrefauthors La Palombara , N. , Esposito , P. , Pintore , F. , Sidoli , L. , Mereghetti , S. \ Tiengo , A. APACrefauthors \ 2018 11 , 619 A126 . APACrefDOI doi:10.1051/0004-6361/201833907 APACrefDOI

    2018 doi

  5. [13]

    \ Mereghetti , S

    LaPalombara+06 APACrefauthors La Palombara , N. \ Mereghetti , S. APACrefauthors \ 2006 08 , 455 1 283-289 . APACrefDOI doi:10.1051/0004-6361:20065107 APACrefDOI

    2006 doi

  6. [14]

    \ Mereghetti , S

    LaPalombara+07 APACrefauthors La Palombara , N. \ Mereghetti , S. APACrefauthors \ 2007 10 , 474 1 137-143 . APACrefDOI doi:10.1051/0004-6361:20077970 APACrefDOI

    2007 doi

  7. [15]

    , Sidoli , L

    LaPalombara+21 APACrefauthors La Palombara , N. , Sidoli , L. , Esposito , P. , Israel , G L. \ Rodr \' guez Castillo , G A. APACrefauthors \ 2021 05 , 649 A118 . APACrefDOI doi:10.1051/0004-6361/202140760 APACrefDOI

    2021 doi

  8. [16]

    , Sidoli , L

    LaPalombara+09 APACrefauthors La Palombara , N. , Sidoli , L. , Esposito , P. , Tiengo , A. \ Mereghetti , S. APACrefauthors \ 2009 10 , 505 3 947-954 . APACrefDOI doi:10.1051/0004-6361/200912538 APACrefDOI

    2009 doi

  9. [17]

    , Sidoli , L

    LaPalombara+12 APACrefauthors La Palombara , N. , Sidoli , L. , Esposito , P. , Tiengo , A. \ Mereghetti , S. APACrefauthors \ 2012 03 , 539 A82 . APACrefDOI doi:10.1051/0004-6361/201118221 APACrefDOI

    2012 doi

  10. [18]

    , Becker , P A

    Li+24 APACrefauthors Li , P P. , Becker , P A. \ Tao , L. APACrefauthors \ 2024 09 , 689 A316 . APACrefDOI doi:10.1051/0004-6361/202450149 APACrefDOI

    2024 doi

  11. [19]

    , Dal Fiume , D

    Masetti+04 APACrefauthors Masetti , N. , Dal Fiume , D. , Amati , L. , Del Sordo , S. , Frontera , F. , Orlandini , M. \ Palazzi , E. APACrefauthors \ 2004 08 , 423 311-319 . APACrefDOI doi:10.1051/0004-6361:20040273 APACrefDOI

    2004 doi

  12. [20]

    , Norton , A J

    Mason+24 APACrefauthors Mason , A B. , Norton , A J. , Clark , J S. , Farrell , S A. \ Gosling , A J. APACrefauthors \ 2024 02 , 41 e008 . APACrefDOI doi:10.1017/pasa.2024.6 APACrefDOI

    2024 doi

  13. [21]

    \ Paul , B

    MukherjeePaul05 APACrefauthors Mukherjee , U. \ Paul , B. APACrefauthors \ 2005 02 , 431 667-672 . APACrefDOI doi:10.1051/0004-6361:20041665 APACrefDOI

    2005 doi

  14. [22]

    \ Paul , B

    NaikPaul04 APACrefauthors Naik , S. \ Paul , B. APACrefauthors \ 2004 01 , 600 1 351-357 . APACrefDOI doi:10.1086/379803 APACrefDOI

    2004 doi

  15. [23]

    , Nagase , F

    Paul+02 APACrefauthors Paul , B. , Nagase , F. , Endo , T. , Dotani , T. , Yokogawa , J. \ Nishiuchi , M. APACrefauthors \ 2002 11 , 579 1 411-421 . APACrefDOI doi:10.1086/342701 APACrefDOI

    2002 doi

  16. [24]

    , Rappaport , S

    Pfahl+02 APACrefauthors Pfahl , E. , Rappaport , S. , Podsiadlowski , P. \ Spruit , H. APACrefauthors \ 2002 07 , 574 1 364-376 . APACrefDOI doi:10.1086/340794 APACrefDOI

    2002 doi

  17. [25]

    , Maitra , C

    Pradhan+13 APACrefauthors Pradhan , P. , Maitra , C. , Paul , B. \ Paul , B C. APACrefauthors \ 2013 12 , 436 2 945-952 . APACrefDOI doi:10.1093/mnras/stt1504 APACrefDOI

    2013 doi

  18. [26]

    \ Roche , P

    ReigRoche99 APACrefauthors Reig , P. \ Roche , P. APACrefauthors \ 1999 06 , 306 1 100-106 . APACrefDOI doi:10.1046/j.1365-8711.1999.02473.x APACrefDOI

    1999

  19. [28]

    , Torrej \'o n , J M

    Reig+09 APACrefauthors Reig , P. , Torrej \'o n , J M. , Negueruela , I. , Blay , P. , Rib \'o , M. \ Wilms , J. APACrefauthors \ 2009 02 , 494 3 1073-1082 . APACrefDOI doi:10.1051/0004-6361:200810950 APACrefDOI

    2009 doi

  20. [29]

    , Sidoli , L

    Sguera+23 APACrefauthors Sguera , V. , Sidoli , L. , Bird , A J. \ La Palombara , N. APACrefauthors \ 2023 07 , 523 1 1192-1198 . APACrefDOI doi:10.1093/mnras/stad1494 APACrefDOI

    2023 doi

  21. [30]

    , Romano , P

    Sidoli+09 APACrefauthors Sidoli , L. , Romano , P. , Ducci , L. \ et al. APACrefauthors \ 2009 08 , 397 3 1528-1538 . APACrefDOI doi:10.1111/j.1365-2966.2009.15049.x APACrefDOI

    2009

  22. [31]

    , Romano , P

    Sidoli+07 APACrefauthors Sidoli , L. , Romano , P. , Mereghetti , S. , Paizis , A. , Vercellone , S. , Mangano , V. \ G \"o tz , D. APACrefauthors \ 2007 12 , 476 3 1307-1315 . APACrefDOI doi:10.1051/0004-6361:20078137 APACrefDOI

    2007 doi

  23. [32]

    , Bedford , D K

    Skinner+82 APACrefauthors Skinner , G K. , Bedford , D K. , Elsner , R F. , Leahy , D. , Weisskopf , M C. \ Grindlay , J. APACrefauthors \ 1982 06 , 297 5867 568-570 . APACrefDOI doi:10.1038/297568a0 APACrefDOI

    1982 doi

  24. [33]

    , Kreykenbohm , I

    Torrejon+04 APACrefauthors Torrej \'o n , J M. , Kreykenbohm , I. , Orr , A. , Titarchuk , L. \ Negueruela , I. APACrefauthors \ 2004 08 , 423 301-309 . APACrefDOI doi:10.1051/0004-6361:20035743 APACrefDOI

    2004 doi

  25. [34]

    , Reig , P

    Torrejon+18 APACrefauthors Torrej \'o n , J M. , Reig , P. , F \"u rst , F. , Martinez-Chicharro , M. , Postnov , K. \ Oskinova , L. APACrefauthors \ 2018 09 , 479 3 3366-3372 . APACrefDOI doi:10.1093/mnras/sty1628 APACrefDOI

    2018 doi

  26. [35]

    , Krivonos , R A

    Tsygankov+12 APACrefauthors Tsygankov , S S. , Krivonos , R A. \ Lutovinov , A A. APACrefauthors \ 2012 04 , 421 3 2407-2413 . APACrefDOI doi:10.1111/j.1365-2966.2012.20475.x APACrefDOI

    2012

  27. [36]

    , Clark , G W

    Woo+95 APACrefauthors Woo , J W. , Clark , G W. , Blondin , J M. , Kallman , T R. \ Nagase , F. APACrefauthors \ 1995 06 , 445 896 . APACrefDOI doi:10.1086/175749 APACrefDOI

    1995 doi

  28. [37]

    , Clark , G W

    Woo+96 APACrefauthors Woo , J W. , Clark , G W. , Levine , A M. , Corbet , R H D. \ Nagase , F. APACrefauthors \ 1996 08 , 467 811 . APACrefDOI doi:10.1086/177655 APACrefDOI

    1996 doi

  29. [38]

    , Paul , B

    Yokogawa+00 APACrefauthors Yokogawa , J. , Paul , B. , Ozaki , M. , Nagase , F. , Chakrabarty , D. \ Takeshima , T. APACrefauthors \ 2000 08 , 539 1 191-196 . APACrefDOI doi:10.1086/309202 APACrefDOI

    doi

Pith tools

Reviewed August 12, 2026 · model on record in the stance chip above.