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arxiv: 2606.08598 · v1 · pith:2FOLLWDRnew · submitted 2026-06-07 · 🌌 astro-ph.HE

Discovery of a Candidate 2 keV Cyclotron Resonance Scattering Feature in the HLX NGC 3583 X-1

Kiran M. Jayasurya , Aman Upadhyay , Vikram Rana This is my paper

Pith reviewed 2026-06-27 17:58 UTC · model grok-4.3

classification 🌌 astro-ph.HE
keywords hyperluminous X-ray sourcecyclotron resonance scattering featureneutron starNGC 3583X-ray spectroscopymagnetic fieldaccretion
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The pith

An absorption line at 1.97 keV in NGC 3583 X-1 is interpreted as a proton cyclotron feature from a neutron star with a magnetic field of 4 x 10^14 G.

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

The paper examines multi-mission X-ray data on the transient hyperluminous source in NGC 3583 and reports a significant absorption line at 1.97 keV. The authors model the broadband spectrum as a combination of thermal and Comptonized components with a cutoff near 5-6 keV and attribute the line to a proton cyclotron resonance scattering feature. If this identification is correct, the implied magnetic field strength and the source's extreme luminosity together indicate that the accretor is a highly magnetized neutron star. This reading favors a neutron-star explanation over a black-hole one for at least this HLX.

Core claim

The central claim is that the combination of luminosities above 10^41 erg s^-1, a hard spectral state, and the 3.9-sigma absorption line at 1.97 keV supplies strong evidence for a highly magnetized neutron star accretor. The line width and energy yield a local field of approximately 4 x 10^14 G when interpreted as a proton CRSF; outflow or atomic-line alternatives are judged less likely. No coherent pulsations are detected, but the spectral and luminosity properties are presented as consistent with magnetized neutron-star accretion.

What carries the argument

The candidate proton cyclotron resonance scattering feature (CRSF) at 1.97 keV, whose energy directly encodes the local magnetic field strength through the proton cyclotron resonance relation.

If this is right

  • The accretor is a neutron star rather than a black hole.
  • The surface magnetic field reaches magnetar-range strengths.
  • Hyperluminous X-ray sources can be powered by accretion onto strongly magnetized neutron stars.
  • The observed spectral cutoff and variability are consistent with Comptonization in a magnetized accretion flow.

Where Pith is reading between the lines

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

  • Similar low-energy absorption features may appear in other HLXs once observed with comparable sensitivity and broadband coverage.
  • Population studies of HLXs could separate neutron-star and black-hole systems by searching for cyclotron lines below 10 keV.
  • Phase-resolved or higher-resolution spectra could test whether the line energy or depth varies with pulse phase if pulsations are eventually detected.

Load-bearing premise

The 1.97 keV absorption line is a proton cyclotron resonance scattering feature produced in the neutron star's magnetic field rather than an ionized outflow or other process.

What would settle it

A higher-signal X-ray spectrum in which the line is either absent or is better fit by an absorption feature from an ionized wind with a different velocity or ionization parameter.

Figures

Figures reproduced from arXiv: 2606.08598 by Aman Upadhyay, Kiran M. Jayasurya, Vikram Rana.

Figure 1
Figure 1. Figure 1: Long-term X-ray variability of NGC 3583 X-1. Top Panel: Evolution of the 0.3–10 keV count rate. Black circles denote Swift/XRT detections, red circles with downward arrows indicate 3σ upper limits for non-detections, and the purple circles denote the 2017 Chandra observation (converted to equivalent Swift/XRT rate). Middle Panel: Evolution of the logarithm of the unabsorbed X-ray luminosity (LX) in the 0.3… view at source ↗
Figure 2
Figure 2. Figure 2: Barycentric-corrected and background-sub￾tracted light curves for NGC 3583 X-1. The top and middle panels show the 0.3–10 keV EPIC-pn data for the 2022 and 2024 epochs, respectively, binned at 500 s. The bottom panel displays the 3–15 keV NuSTAR FPMA data binned at 6 ks. The horizontal axis represents time in kiloseconds (ks), and the vertical axis shows the count rate in counts s−1 . To check for quasi-pe… view at source ↗
Figure 3
Figure 3. Figure 3: Spectral fit to the 2022 XMM-Newton data using Model M5 (TBabs*(diskbb+compTT)). Top panel: Spectrum unfolded through the instrumental response assuming the best-fit model, shown as E 2F(E), with the individual model components overplotted: diskbb (dashed) and compTT (dot￾ted). Bottom panel: Residuals with respect to the continuum model. Data in both panels are rebinned for visual clarity. 4.2. 2024: Joint… view at source ↗
Figure 4
Figure 4. Figure 4: Spectral fit to the 2024 XMM-New￾ton+NuSTAR data. Top panel: Spectrum unfolded through the instrumental response assuming the best– fit continuum+line model, TBabs*gabs*(diskbb+compTT), shown as E 2F(E), with the individual continuum com￾ponents overplotted: diskbb (dashed) and compTT (dot￾ted). Middle panel: Residuals with respect to the continuum-only model, TBabs*(diskbb+compTT). Bottom panel: Residuals… view at source ↗
Figure 5
Figure 5. Figure 5: Spectral residuals from fitting the 2024 simulta￾neous XMM-Newton+NuSTAR data in the 0.3–15 keV band. Data from EPIC-pn (black), EPIC-MOS2 (red), FPMA (or￾ange), and FPMB (blue) are plotted. Panel (a) shows the residuals for the models M1-M5. Panel (b) shows the residuals for the models TBabs*gabs*(diskbb+compTT) and TBabs*zxipab*(diskbb+compTT), which account for the ab￾sorption feature. For all three mod… view at source ↗
Figure 6
Figure 6. Figure 6: Distribution of the maximum improvement in the fit statistic (∆C) obtained from 10, 000 simulated spec￾tra generated from the continuum-only model M3. The ver￾tical, dashed, black line indicates the observed improvement (∆C = −24.34) from the real data. None of the simu￾lated random fluctuations in the continuum produced a ∆C greater than the observed value, implying a False Alarm Rate (FAR) of < 10−4 and … view at source ↗
Figure 8
Figure 8. Figure 8: The improvement in the C-statistic (|∆C|) result￾ing from a blind Gaussian line scan across the joint spectral continuum as a function of energy. The scan used Gaussian absorption profiles with fractional widths (σline/Eline) fixed at 0.05 and 0.1 to represent line morphologies typically as￾sociated with proton and electron CRSFs, respectively. model quantify the magnitude of continuum attenua￾tion at each… view at source ↗
Figure 9
Figure 9. Figure 9: (a) Hardness–Intensity Diagram (HID) of NGC 3583 X-1 comparing the 2022 (blue) and 2024 (red) epochs. (b) Color Color Diagram (CCD) of the source com￾paring its hardness and softness during the 2022 (blue) and 2024 (red) epochs with known PULXs NGC 5907 ULX1 (ma￾genta), NGC 7793 P13 (green) and NGC 1313 X-2 (orange). All error bars correspond to 1σ uncertainties. See text for details. 5. DISCUSSION 5.1. Br… view at source ↗
read the original abstract

We present a broadband X-ray study of the transient hyperluminous X-ray source (HLX), 2SXPS J111416.1+481833, in the galaxy NGC 3583, using archival XMM-Newton, NuSTAR, Chandra data, and long-term Swift/XRT monitoring. The source episodically enters the hyperluminous regime with X-ray luminosities $L_X > 10^{41}$ erg s$^{-1}$ and drops by a factor of $>45$ from its peak into a deep low state. We detect a clear spectral cutoff at $\sim$5-6 keV in the broadband spectra, which are well modeled by a soft thermal component combined with optically thick thermal Comptonization or an inner advection-dominated disk. In the XMM-Newton spectra, we detect a statistically significant ($\gtrsim 3.9 \sigma$) absorption line centered at $E_{\rm line} \approx 1.97 \pm 0.04$ keV with a width of $\sigma_{\rm line} \approx 74 \pm 40$ eV. We primarily interpret the line as a candidate proton Cyclotron Resonance Scattering Feature (CRSF), implying a local magnetic field strength of $B \sim 4 \times 10^{14}$ G. Alternative interpretations, such as an origin in an ionized outflow, were explored and found to be less likely. We do not detect coherent X-ray pulsations, placing 90% confidence upper limits on the pulsed fraction of 19.3% in the 0.3-10 keV band and 36.3% in the 3-15 keV band. The combination of extreme luminosity, a hard spectral state, and the detection of a candidate cyclotron line provides strong evidence for a highly magnetized neutron star accretor.

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 reports a broadband X-ray analysis of the transient HLX 2SXPS J111416.1+481833 in NGC 3583 using archival XMM-Newton, NuSTAR, Chandra, and Swift/XRT data. The source reaches L_X > 10^41 erg s^{-1} episodically before dropping by factors >45. Spectra show a cutoff at ~5-6 keV, modeled as a soft thermal component plus optically thick Comptonization or an ADAF. An absorption line at E_line ≈ 1.97 ± 0.04 keV (width σ_line ≈ 74 ± 40 eV) is detected at ≳3.9σ in the XMM-Newton spectra and interpreted primarily as a proton CRSF implying B ~ 4×10^14 G; ionized-outflow alternatives are stated to be less likely. No coherent pulsations are detected (90% upper limits 19.3% in 0.3-10 keV and 36.3% in 3-15 keV). The combination of extreme luminosity, hard state, and candidate CRSF is presented as strong evidence for a highly magnetized neutron-star accretor.

Significance. If the line identification holds, the result would be significant for HLX/ULX studies by supplying rare direct evidence of an ultra-strong magnetic field and favoring a neutron-star accretor over a black-hole interpretation. The reported combination of hyperluminous output in a hard spectral state with a candidate proton CRSF is noteworthy and could help constrain accretion physics at extreme luminosities.

major comments (2)
  1. [Abstract] Abstract: the statement that 'alternative interpretations, such as an origin in an ionized outflow, were explored and found to be less likely' is load-bearing for the central NS-accretor claim yet supplies no quantitative details on (i) the exact continuum model and fit statistic improvement when the line is added, (ii) any look-elsewhere correction applied while scanning line energy, or (iii) the ionization parameter, column, or velocity values that quantitatively disfavor a wind origin. These omissions prevent independent assessment of whether the CRSF interpretation is preferred.
  2. [Abstract] Abstract: the reported ≳3.9σ significance of the 1.97 keV feature is presented without stating whether a trials factor for the line-energy search was included; if the search was performed over a broad energy range, the effective significance could be lower and would directly affect the weight given to the magnetar interpretation.
minor comments (2)
  1. [Title/Abstract] The title refers to 'NGC 3583 X-1' while the abstract uses the 2SXPS catalog name; adopt a single consistent source designation throughout.
  2. [Abstract] Clarify whether the quoted line width (74 ± 40 eV) is the Gaussian σ or the FWHM.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful review and constructive feedback. We address each major comment below and will revise the manuscript to supply the requested quantitative details.

read point-by-point responses

  1. Referee: [Abstract] Abstract: the statement that 'alternative interpretations, such as an origin in an ionized outflow, were explored and found to be less likely' is load-bearing for the central NS-accretor claim yet supplies no quantitative details on (i) the exact continuum model and fit statistic improvement when the line is added, (ii) any look-elsewhere correction applied while scanning line energy, or (iii) the ionization parameter, column, or velocity values that quantitatively disfavor a wind origin. These omissions prevent independent assessment of whether the CRSF interpretation is preferred.

    Authors: We agree the abstract is concise and omits these specifics. The main text (Section 3) details the continuum models (soft thermal + Comptonization/ADAF) and reports the line detection, but we will add explicit quantitative information in the revised manuscript: fit-statistic improvements upon adding the Gaussian line, the precise energy search range and any trials correction applied, and the best-fit wind parameters (ionization, column, velocity) that were tested and disfavored relative to the CRSF model. A short reference to these results will also be incorporated into the abstract. revision: yes

  2. Referee: [Abstract] Abstract: the reported ≳3.9σ significance of the 1.97 keV feature is presented without stating whether a trials factor for the line-energy search was included; if the search was performed over a broad energy range, the effective significance could be lower and would directly affect the weight given to the magnetar interpretation.

    Authors: The quoted ≳3.9σ is the local significance from the spectral fit at the best-fit energy. We will revise the manuscript to state explicitly the energy range scanned for the line feature and whether a trials factor was applied. If the search was performed over a limited range around the expected CRSF energy, no correction is required; otherwise we will report the trials-corrected value or discuss its impact on the claimed significance. revision: yes

Circularity Check

0 steps flagged

No circularity: purely observational line detection and model comparison

full rationale

The paper performs archival X-ray spectral fitting on XMM-Newton, NuSTAR, Chandra, and Swift data for the HLX source. The claimed result is a statistically significant absorption feature at ~1.97 keV whose identification as a proton CRSF is presented as an interpretation after exploring (but not quantitatively detailing) outflow alternatives. No equation chain, parameter fit, or self-citation is invoked to derive the line energy, width, or magnetic-field implication from the paper's own inputs; the detection significance and model preference are reported as direct data products. The analysis is therefore self-contained against external spectral benchmarks and does not reduce any prediction to a fitted quantity by construction.

Axiom & Free-Parameter Ledger

2 free parameters · 2 axioms · 0 invented entities

The magnetic field value is obtained by applying the standard proton cyclotron energy formula to the fitted line energy; the main load-bearing step is the line identification itself.

free parameters (2)
  • Line centroid energy = 1.97 keV
    Fitted from the XMM-Newton spectrum
  • Line width = 74 eV
    Fitted Gaussian sigma
axioms (2)
  • standard math Standard proton cyclotron resonance energy-to-B conversion formula
    Used to translate observed line energy into B ~ 4e14 G
  • domain assumption The line origin is cyclotron resonance rather than outflow or other process
    Primary interpretation after alternatives were explored

pith-pipeline@v0.9.1-grok · 5888 in / 1470 out tokens · 31698 ms · 2026-06-27T17:58:35.666358+00:00 · methodology

discussion (0)

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Works this paper leans on

107 extracted references · 99 canonical work pages · 3 internal anchors

  1. [1]

    2021, ApJL, 917, L31, doi: 10.3847/2041-8213/ac1859

    Abarca, D., Parfrey, K., & Klu´ zniak, W. 2021, ApJL, 917, L31, doi: 10.3847/2041-8213/ac1859

    work page doi:10.3847/2041-8213/ac1859 2021

  2. [2]

    , keywords =

    Szuszkiewicz, E. 1988, ApJ, 332, 646, doi: 10.1086/166683

    work page doi:10.1086/166683 1988

  3. [3]

    arXiv , author =:2507.14875 , journal =

    Amato, R., Quintin, E., Tranin, H., et al. 2025, A&A, 701, A7, doi: 10.1051/0004-6361/202555122

    work page doi:10.1051/0004-6361/202555122 2025

  4. [4]

    Arnaud, K. A. 1996, in Astronomical Society of the Pacific Conference Series, Vol. 101, Astronomical Data Analysis Software and Systems V, ed. G. H. Jacoby & J. Barnes, 17

    1996

  5. [5]

    2018, HENDRICS: High ENergy Data Reduction Interface from the Command Shell,, Astrophysics Source Code Library, record ascl:1805.019 http://ascl.net/1805.019

    Bachetti, M. 2018, HENDRICS: High ENergy Data Reduction Interface from the Command Shell,, Astrophysics Source Code Library, record ascl:1805.019 http://ascl.net/1805.019

    2018

  6. [6]

    doi:10.1038/nature13791 , eprint =

    Bachetti, M., Harrison, F. A., Walton, D. J., et al. 2014, Nature, 514, 202, doi: 10.1038/nature13791

    work page doi:10.1038/nature13791 2014

  7. [7]

    D., Williams, D

    Baldi, R. D., Williams, D. R. A., McHardy, I. M., et al. 2018, MNRAS, 476, 3478, doi: 10.1093/mnras/sty342

    work page doi:10.1093/mnras/sty342 2018

  8. [8]

    Begelman, M. C. 2002, ApJL, 568, L97, doi: 10.1086/340457

    work page doi:10.1086/340457 2002

  9. [9]

    arXiv , author =:2203.11955 , journal =

    Brightman, M., Kosec, P., F¨ urst, F., et al. 2022, ApJ, 929, 138, doi: 10.3847/1538-4357/ac5e37

    work page doi:10.3847/1538-4357/ac5e37 2022

  10. [10]

    doi:10.1038/s41550-018-0391-6 , eprint =

    Brightman, M., Harrison, F. A., F¨ urst, F., et al. 2018, Nature Astronomy, 2, 312, doi: 10.1038/s41550-018-0391-6

    work page doi:10.1038/s41550-018-0391-6 2018

  11. [11]

    1971, PhRvD, 3, 2303, doi: 10.1103/PhysRevD.3.2303

    Canuto, V., Lodenquai, J., & Ruderman, M. 1971, PhRvD, 3, 2303, doi: 10.1103/PhysRevD.3.2303

    work page doi:10.1103/physrevd.3.2303 1971

  12. [12]

    doi:10.1093/mnrasl/sly030 , eprint =

    Carpano, S., Haberl, F., Maitra, C., & Vasilopoulos, G. 2018, MNRAS, 476, L45, doi: 10.1093/mnrasl/sly030

    work page doi:10.1093/mnrasl/sly030 2018

  13. [13]

    1979, ApJ, 228, 939, doi: 10.1086/156922

    Cash, W. 1979, ApJ, 228, 939, doi: 10.1086/156922

    work page doi:10.1086/156922 1979

  14. [14]

    A., Rothschild, R

    Coburn, W., Heindl, W. A., Rothschild, R. E., et al. 2002, ApJ, 580, 394, doi: 10.1086/343033

    work page doi:10.1086/343033 2002

  15. [15]

    Colbert, E. J. M., & Mushotzky, R. F. 1999, ApJ, 519, 89, doi: 10.1086/307356

    work page doi:10.1086/307356 1999

  16. [16]

    A., Fogantini, F

    Cruz-Sanchez, N., Saavedra, E. A., Fogantini, F. A., Garc´ ıa, F., & Combi, J. A. 2026a, A&A, 705, A136, doi: 10.1051/0004-6361/202556922

    work page doi:10.1051/0004-6361/202556922

  17. [17]

    A., Fogantini, F

    Cruz-Sanchez, N., Saavedra, E. A., Fogantini, F. A., et al. 2026b, A&A, 707, L20, doi: 10.1051/0004-6361/202658875

    work page doi:10.1051/0004-6361/202658875

  18. [18]

    K., & Ventura, J

    Daugherty, J. K., & Ventura, J. 1977, A&A, 61, 723

    1977

  19. [19]

    2025, ApJL, 994, L38, doi: 10.3847/2041-8213/ae1c42

    Ducci, L., Mereghetti, S., Pintore, F., et al. 2025, ApJL, 994, L38, doi: 10.3847/2041-8213/ae1c42

    work page doi:10.3847/2041-8213/ae1c42 2025

  20. [20]

    P., Brightman, M., Harrison, F

    Earnshaw, H. P., Brightman, M., Harrison, F. A., et al. 2022, ApJ, 934, 42, doi: 10.3847/1538-4357/ac79b0

    work page doi:10.3847/1538-4357/ac79b0 2022

  21. [21]

    P., Bachetti, M., Brightman, M., et al

    Earnshaw, H. P., Bachetti, M., Brightman, M., et al. 2024, ApJ, 968, 111, doi: 10.3847/1538-4357/ad43d9

    work page doi:10.3847/1538-4357/ad43d9 2024

  22. [22]

    2003, ApJ, 597, 780, doi: 10.1086/378586

    Ebisawa, K., ˙Zycki, P., Kubota, A., Mizuno, T., & Watarai, K.-y. 2003, ApJ, 597, 780, doi: 10.1086/378586

    work page doi:10.1086/378586 2003

  23. [23]

    2008, PASJ, 60, S57, doi: 10.1093/pasj/60.sp1.S57

    Enoto, T., Makishima, K., Terada, Y., et al. 2008, PASJ, 60, S57, doi: 10.1093/pasj/60.sp1.S57

    work page doi:10.1093/pasj/60.sp1.s57 2008

  24. [24]

    Astronomy & Astrophysics , year = 2007, volume = 469, number = 1, pages =

    Evans, P. A., Beardmore, A. P., Page, K. L., et al. 2007, A&A, 469, 379, doi: 10.1051/0004-6361:20077530

    work page doi:10.1051/0004-6361:20077530 2007

  25. [25]

    , keywords =

    Evans, P. A., Beardmore, A. P., Page, K. L., et al. 2009, MNRAS, 397, 1177, doi: 10.1111/j.1365-2966.2009.14913.x

    work page doi:10.1111/j.1365-2966.2009.14913.x 2009

  26. [26]

    Rodrigues, J. M. 2009, Nature, 460, 73, doi: 10.1038/nature08083

    work page doi:10.1038/nature08083 2009

  27. [27]

    2011, NewAR, 55, 166, doi: 10.1016/j.newar.2011.08.002

    Feng, H., & Soria, R. 2011, NewAR, 55, 166, doi: 10.1016/j.newar.2011.08.002

    work page doi:10.1016/j.newar.2011.08.002 2011

  28. [28]

    C., Allen, G

    Fruscione, A., McDowell, J. C., Allen, G. E., et al. 2006, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, Vol. 6270, Observatory Operations: Strategies, Processes, and Systems, ed. D. R. Silva & R. E. Doxsey, 62701V, doi: 10.1117/12.671760 F¨ urst, F., Walton, D. J., Harrison, F. A., et al. 2016, ApJL, 831, L14, doi: 10.38...

    work page doi:10.1117/12.671760 2006

  29. [29]

    J., et al

    Gabriel, C., Denby, M., Fyfe, D. J., et al. 2004, in Astronomical Society of the Pacific Conference Series, Vol. 314, Astronomical Data Analysis Software and Systems (ADASS) XIII, ed. F. Ochsenbein, M. G. Allen, & D. Egret, 759

    2004

  30. [30]

    2021, MNRAS, 504, 974, doi: 10.1093/mnras/stab774

    Ghosh, T., & Rana, V. 2021, MNRAS, 504, 974, doi: 10.1093/mnras/stab774

    work page doi:10.1093/mnras/stab774 2021

  31. [31]

    2023, ApJ, 949, 78, doi: 10.3847/1538-4357/acccf4

    Ghosh, T., & Rana, V. 2023, ApJ, 949, 78, doi: 10.3847/1538-4357/acccf4

    work page doi:10.3847/1538-4357/acccf4 2023

  32. [32]

    2022, ApJ, 938, 76, doi: 10.3847/1538-4357/ac8f8f

    Ghosh, T., Rana, V., & Bachetti, M. 2022, ApJ, 938, 76, doi: 10.3847/1538-4357/ac8f8f

    work page doi:10.3847/1538-4357/ac8f8f 2022

  33. [33]

    C., et al

    Ghosh, T., Sethi, S., Dewangan, G. C., et al. 2025, arXiv e-prints, arXiv:2511.10183, doi: 10.48550/arXiv.2511.10183

    work page doi:10.48550/arxiv.2511.10183 2025

  34. [34]

    , keywords =

    Gladstone, J. C., Roberts, T. P., & Done, C. 2009, MNRAS, 397, 1836, doi: 10.1111/j.1365-2966.2009.15123.x

    work page doi:10.1111/j.1365-2966.2009.15123.x 2009

  35. [35]

    K., & Daugherty, J

    Harding, A. K., & Daugherty, J. K. 1991, ApJ, 374, 687, doi: 10.1086/170153 19

    work page doi:10.1086/170153 1991

  36. [36]

    K., & Lai, D

    Harding, A. K., & Lai, D. 2006, Reports on Progress in Physics, 69, 2631, doi: 10.1088/0034-4885/69/9/R03

    work page doi:10.1088/0034-4885/69/9/r03 2006

  37. [37]

    , archivePrefix = "arXiv", eprint =

    Harrison, F. A., Craig, W. W., Christensen, F. E., et al. 2013, ApJ, 770, 103, doi: 10.1088/0004-637X/770/2/103

    work page doi:10.1088/0004-637x/770/2/103 2013

  38. [38]

    Ho, W. C. G., & Lai, D. 2001, MNRAS, 327, 1081, doi: 10.1046/j.1365-8711.2001.04801.x

    work page doi:10.1046/j.1365-8711.2001.04801.x 2001

  39. [39]

    L., et al

    Huppenkothen, D., Bachetti, M., Stevens, A. L., et al. 2019, ApJ, 881, 39, doi: 10.3847/1538-4357/ab258d

    work page doi:10.3847/1538-4357/ab258d 2019

  40. [40]

    I., Safi-Harb, S., Swank, J

    Ibrahim, A. I., Safi-Harb, S., Swank, J. H., et al. 2002, ApJL, 574, L51, doi: 10.1086/342366

    work page doi:10.1086/342366 2002

  41. [41]

    F., & Sunyaev, R

    Illarionov, A. F., & Sunyaev, R. A. 1975, A&A, 39, 185

    1975

  42. [42]

    2021, ApJ, 919, 90, doi: 10.3847/1538-4357/ac134e

    Islam, N., & Mukai, K. 2021, ApJ, 919, 90, doi: 10.3847/1538-4357/ac134e

    work page doi:10.3847/1538-4357/ac134e 2021

  43. [43]

    L., Belfiore, A., Stella, L., et al

    Israel, G. L., Belfiore, A., Stella, L., et al. 2017a, Science, 355, 817, doi: 10.1126/science.aai8635

    work page doi:10.1126/science.aai8635

  44. [44]

    L., Papitto, A., Esposito, P., et al

    Israel, G. L., Papitto, A., Esposito, P., et al. 2017b, MNRAS, 466, L48, doi: 10.1093/mnrasl/slw218

    work page doi:10.1093/mnrasl/slw218

  45. [45]

    Kaaret, P., Feng, H., & Roberts, T. P. 2017, ARA&A, 55, 303, doi: 10.1146/annurev-astro-091916-055259

    work page doi:10.1146/annurev-astro-091916-055259 2017

  46. [46]

    2020, MNRAS, 494, 3611, doi: 10.1093/mnras/staa930

    King, A., & Lasota, J.-P. 2020, MNRAS, 494, 3611, doi: 10.1093/mnras/staa930

    work page doi:10.1093/mnras/staa930 2020

  47. [47]

    2023, NewAR, 96, 101672, doi: 10.1016/j.newar.2022.101672

    King, A., Lasota, J.-P., & Middleton, M. 2023, NewAR, 96, 101672, doi: 10.1016/j.newar.2022.101672

    work page doi:10.1016/j.newar.2022.101672 2023

  48. [48]

    King, A., & Muldrew, S. I. 2016, MNRAS, 455, 1211, doi: 10.1093/mnras/stv2347

    work page doi:10.1093/mnras/stv2347 2016

  49. [49]

    2001, ApJL, 552, L109, doi: 10.1086/320343

    Elvis, M. 2001, ApJL, 552, L109, doi: 10.1086/320343

    work page doi:10.1086/320343 2001

  50. [50]

    R., et al

    Kobayashi, H., Ohsuga, K., Takahashi, H. R., et al. 2018, PASJ, 70, 22, doi: 10.1093/pasj/psx157 K¨ ording, E., Falcke, H., & Markoff, S. 2002, A&A, 382, L13, doi: 10.1051/0004-6361:20011776

    work page doi:10.1093/pasj/psx157 2018

  51. [51]

    J., et al

    Kosec, P., Pinto, C., Walton, D. J., et al. 2018, MNRAS, 479, 3978, doi: 10.1093/mnras/sty1626

    work page doi:10.1093/mnras/sty1626 2018

  52. [52]

    S., et al

    Kosec, P., Pinto, C., Reynolds, C. S., et al. 2021, MNRAS, 508, 3569, doi: 10.1093/mnras/stab2856

    work page doi:10.1093/mnras/stab2856 2021

  53. [53]

    1998, PASJ, 50, 667, doi: 10.1093/pasj/50.6.667

    Kubota, A., Tanaka, Y., Makishima, K., et al. 1998, PASJ, 50, 667, doi: 10.1093/pasj/50.6.667

    work page doi:10.1093/pasj/50.6.667 1998

  54. [54]

    2017, Nature Astronomy, 1, 0033, doi: 10.1038/s41550-016-0033

    Lin, D., Guillochon, J., Komossa, S., et al. 2017, Nature Astronomy, 1, 0033, doi: 10.1038/s41550-016-0033

    work page doi:10.1038/s41550-016-0033 2017

  55. [55]

    P., Mineo, S., et al

    Luangtip, W., Roberts, T. P., Mineo, S., et al. 2015, MNRAS, 446, 470, doi: 10.1093/mnras/stu2086

    work page doi:10.1093/mnras/stu2086 2015

  56. [56]

    E., & Syunyaev, R

    Lyubarskii, Y. E., & Syunyaev, R. A. 1988, Soviet Astronomy Letters, 14, 390

    1988

  57. [57]

    1990, ApJL, 365, L59, doi: 10.1086/185888

    Makishima, K., Mihara, T., Ishida, M., et al. 1990, ApJL, 365, L59, doi: 10.1086/185888

    work page doi:10.1086/185888 1990

  58. [58]

    2000, ApJ, 535, 632, doi: 10.1086/308868

    Makishima, K., Kubota, A., Mizuno, T., et al. 2000, ApJ, 535, 632, doi: 10.1086/308868

    work page doi:10.1086/308868 2000

  59. [59]

    1992, High-energy radiation from magnetized neutron stars

    Meszaros, P. 1992, High-energy radiation from magnetized neutron stars

    1992

  60. [60]

    J., Brightman, M., Pintore, F., et al

    Middleton, M. J., Brightman, M., Pintore, F., et al. 2019, MNRAS, 486, 2, doi: 10.1093/mnras/stz436

    work page doi:10.1093/mnras/stz436 2019

  61. [61]

    Roberts, T. P. 2015a, MNRAS, 447, 3243, doi: 10.1093/mnras/stu2644

    work page doi:10.1093/mnras/stu2644

  62. [62]

    J., Walton, D

    Middleton, M. J., Walton, D. J., Fabian, A., et al. 2015b, MNRAS, 454, 3134, doi: 10.1093/mnras/stv2214

    work page doi:10.1093/mnras/stv2214

  63. [63]

    1990, Nature, 346, 250, doi: 10.1038/346250a0

    Tashiro, M. 1990, Nature, 346, 250, doi: 10.1038/346250a0

    work page doi:10.1038/346250a0 1990

  64. [64]

    M., Fabian, A

    Miller, J. M., Fabian, A. C., & Miller, M. C. 2004, ApJL, 614, L117, doi: 10.1086/425316

    work page doi:10.1086/425316 2004

  65. [65]

    1994, ApJ, 426, 308, doi: 10.1086/174065

    Fukue, J. 1994, ApJ, 426, 308, doi: 10.1086/174065

    work page doi:10.1086/174065 1994

  66. [66]

    2019, ApJL, 883, L11, doi: 10.3847/2041-8213/ab3e4d

    Molkov, S., Lutovinov, A., Tsygankov, S., Mereminskiy, I., & Mushtukov, A. 2019, ApJL, 883, L11, doi: 10.3847/2041-8213/ab3e4d

    work page doi:10.3847/2041-8213/ab3e4d 2019

  67. [67]

    I., & Poutanen, J

    Nagirner, D. I., & Poutanen, J. 2021, MNRAS, 501, 2424, doi: 10.1093/mnras/staa3809

    work page doi:10.1093/mnras/staa3809 2021

  68. [68]

    2017, MNRAS, 467, 1202, doi: 10.1093/mnras/stx141

    Ingram, A. 2017, MNRAS, 467, 1202, doi: 10.1093/mnras/stx141

    work page doi:10.1093/mnras/stx141 2017

  69. [69]

    2015, MNRAS, 454, 2539, doi: 10.1093/mnras/stv2087 Nasa High Energy Astrophysics Science Archive Research Center (Heasarc)

    Poutanen, J. 2015, MNRAS, 454, 2539, doi: 10.1093/mnras/stv2087 Nasa High Energy Astrophysics Science Archive Research Center (Heasarc). 2014, HEAsoft: Unified Release of FTOOLS and XANADU,, Astrophysics Source Code Library, record ascl:1408.004 http://ascl.net/1408.004

    work page doi:10.1093/mnras/stv2087 2015

  70. [70]

    2015, ApJ, 807, 164, doi: 10.1088/0004-637X/807/2/164

    Nishimura, O. 2015, ApJ, 807, 164, doi: 10.1088/0004-637X/807/2/164

    work page doi:10.1088/0004-637x/807/2/164 2015

  71. [71]

    2007, ApJ, 659, 205, doi: 10.1086/512118

    Ohsuga, K. 2007, ApJ, 659, 205, doi: 10.1086/512118

    work page doi:10.1086/512118 2007

  72. [72]

    , archivePrefix = "arXiv", eprint =

    Ohsuga, K., & Mineshige, S. 2011, ApJ, 736, 2, doi: 10.1088/0004-637X/736/1/2

    work page doi:10.1088/0004-637x/736/1/2 2011

  73. [73]

    2017, Astronomische Nachrichten, 338, 234, doi: 10.1002/asna.201713336

    Pinto, C., Fabian, A., Middleton, M., & Walton, D. 2017, Astronomische Nachrichten, 338, 234, doi: 10.1002/asna.201713336

    work page doi:10.1002/asna.201713336 2017

  74. [74]

    2023, Astronomische Nachrichten, 344, e20220134, doi: 10.1002/asna.20220134

    Pinto, C., & Kosec, P. 2023, Astronomische Nachrichten, 344, e20220134, doi: 10.1002/asna.20220134

    work page doi:10.1002/asna.20220134 2023

  75. [75]

    , keywords =

    Pinto, C., Soria, R., Walton, D. J., et al. 2021, MNRAS, 505, 5058, doi: 10.1093/mnras/stab1648

    work page doi:10.1093/mnras/stab1648 2021

  76. [76]

    2026, A&A, 706, A266, doi: 10.1051/0004-6361/202556631

    Pinto, C., Caserta, S., Barra, F., et al. 2026, A&A, 706, A266, doi: 10.1051/0004-6361/202556631

    work page doi:10.1051/0004-6361/202556631 2026

  77. [77]

    2017, ApJ, 836, 113, doi: 10.3847/1538-4357/836/1/113

    Pintore, F., Zampieri, L., Stella, L., et al. 2017, ApJ, 836, 113, doi: 10.3847/1538-4357/836/1/113

    work page doi:10.3847/1538-4357/836/1/113 2017

  78. [78]

    and Konar, C

    Poutanen, J., Lipunova, G., Fabrika, S., Butkevich, A. G., & Abolmasov, P. 2007, MNRAS, 377, 1187, doi: 10.1111/j.1365-2966.2007.11668.x 20

    work page doi:10.1111/j.1365-2966.2007.11668.x 2007

  79. [79]

    Ransom, S. M. 2002, in Astronomical Society of the Pacific Conference Series, Vol. 271, Neutron Stars in Supernova Remnants, ed. P. O. Slane & B. M. Gaensler, 361, doi: 10.48550/arXiv.astro-ph/0112006

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.astro-ph/0112006 2002

  80. [80]

    2008, MNRAS, 387, L41, doi: 10.1111/j.1745-3933.2008.00480.x

    Reeves, J., Done, C., Pounds, K., et al. 2008, MNRAS, 385, L108, doi: 10.1111/j.1745-3933.2008.00443.x Rodr´ ıguez Castillo, G. A., Israel, G. L., Belfiore, A., et al. 2020, ApJ, 895, 60, doi: 10.3847/1538-4357/ab8a44

    work page doi:10.1111/j.1745-3933.2008.00443.x 2008

Showing first 80 references.