pith. sign in

arxiv: 2606.30729 · v1 · pith:HH6KNFI6new · submitted 2026-06-29 · 🌀 gr-qc

Ray tracing ultracompact boson stars: visibility modulations and incomplete photon rings

Seppe J. Staelens , Ece Alkan This is my paper

Pith reviewed 2026-07-01 02:08 UTC · model grok-4.3

classification 🌀 gr-qc
keywords boson starsphoton ringsvisibility amplituderay tracingblack hole mimickersEvent Horizon Telescopegeneral relativity
0
0 comments X

The pith

Clear visibility modulations from extra photon rings occur only in spherical ultracompact boson stars at limited inclinations, not generically for black-hole mimickers.

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

The paper generates ray-traced images of stable and unstable ultracompact solitonic boson stars, both spherical and rotating, to test whether additional photon rings would produce detectable low-frequency modulations in visibility amplitude. These modulations appear only in the spherical cases and only for a narrow range of observer inclinations. The result indicates that the absence of such modulations in Event Horizon Telescope data would not rule out most rotating ultracompact alternatives. The rotating models also produce incomplete photon rings that may require an unstable prograde light ring to complete.

Core claim

Ray-traced images of stable and unstable ultracompact solitonic boson stars show that clear modulations in the associated visibility amplitude are only present in spherical symmetry, for a restricted range of observer inclinations. This suggests that such modulations cannot be a generic expectation of ultracompact black-hole mimickers. For rotating boson stars the photon rings are incomplete, and an unstable prograde light ring may be needed to remedy this.

What carries the argument

Visibility amplitude extracted from ray-traced images of boson star spacetimes, examined for low-frequency modulations that would signal extra photon rings.

If this is right

  • Additional photon rings in rotating ultracompact objects will not generically imprint low-frequency modulations on visibility data.
  • Rotating boson-star photon rings remain incomplete unless an unstable prograde light ring is present.
  • Absence of visibility modulations in observations cannot be used to exclude most rotating black-hole mimickers.
  • Image features from axisymmetric mimickers may require separate analysis from spherical ones.

Where Pith is reading between the lines

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

  • Applying the same visibility analysis to other mimicker spacetimes such as gravastars or wormholes would test whether the spherical-only result holds more broadly.
  • Incomplete rings in rotating cases may affect how image-reconstruction pipelines interpret partial ring signals.
  • Inclination dependence implies that orientation biases could affect the detectability of any mimicker signatures in surveys.

Load-bearing premise

The specific stable and unstable ultracompact solitonic boson star models examined are representative of the broader class of ultracompact black-hole mimickers capable of producing additional photon rings.

What would settle it

Clear low-frequency modulations appearing in the visibility amplitude of a rotating ultracompact boson star across a wide range of inclinations would falsify the claim that such modulations are not generic.

Figures

Figures reproduced from arXiv: 2606.30729 by Ece Alkan, Seppe J. Staelens.

Figure 1
Figure 1. Figure 1: FIG. 1. Mass [PITH_FULL_IMAGE:figures/full_fig_p003_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. Orbital angular frequency for TCOs as function of [PITH_FULL_IMAGE:figures/full_fig_p005_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. The orbital angular frequencies (7) for the ( [PITH_FULL_IMAGE:figures/full_fig_p005_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. ( [PITH_FULL_IMAGE:figures/full_fig_p008_4.png] view at source ↗
Figure 6
Figure 6. Figure 6: FIG. 6. Estimated period of the low-frequency modulation [PITH_FULL_IMAGE:figures/full_fig_p009_6.png] view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5. Normalised visibility amplitude [PITH_FULL_IMAGE:figures/full_fig_p009_5.png] view at source ↗
Figure 7
Figure 7. Figure 7: FIG. 7. ( [PITH_FULL_IMAGE:figures/full_fig_p010_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: FIG. 8. Comparison of a ( [PITH_FULL_IMAGE:figures/full_fig_p011_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: FIG. 9. Intensity profile along a slice at 10 [PITH_FULL_IMAGE:figures/full_fig_p011_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: FIG. 10. Visibility amplitude along a slice at 10 [PITH_FULL_IMAGE:figures/full_fig_p012_10.png] view at source ↗
Figure 11
Figure 11. Figure 11: FIG. 11. From top to bottom: the [PITH_FULL_IMAGE:figures/full_fig_p012_11.png] view at source ↗
Figure 12
Figure 12. Figure 12: FIG. 12. Visibility amplitudes corresponding to the images [PITH_FULL_IMAGE:figures/full_fig_p012_12.png] view at source ↗
Figure 13
Figure 13. Figure 13: shows the images and some visibility ampli￾tudes for the A044 BS with the above disc model. The image for an equatorial observer is highly asymmetric due to strong Doppler beaming of the emitting matter. In the visibility, we see a clear bump at some angles, but no consistent modulation: this may be largely attributed to the high asymmetry, such that a uniform ring is no longer a good approximation for th… view at source ↗
Figure 15
Figure 15. Figure 15: FIG. 15. Same as Fig. 5, but assuming radially infalling mat [PITH_FULL_IMAGE:figures/full_fig_p016_15.png] view at source ↗
Figure 16
Figure 16. Figure 16: FIG. 16. ( [PITH_FULL_IMAGE:figures/full_fig_p018_16.png] view at source ↗
Figure 18
Figure 18. Figure 18: FIG. 18. Comparison of the normalised visibility amplitudes [PITH_FULL_IMAGE:figures/full_fig_p019_18.png] view at source ↗
Figure 19
Figure 19. Figure 19: FIG. 19. Comparison of the normalised visibility amplitudes [PITH_FULL_IMAGE:figures/full_fig_p019_19.png] view at source ↗
Figure 20
Figure 20. Figure 20: FIG. 20. Comparison of a ( [PITH_FULL_IMAGE:figures/full_fig_p020_20.png] view at source ↗
Figure 21
Figure 21. Figure 21: FIG. 21. Same as Fig. 20, but for the [PITH_FULL_IMAGE:figures/full_fig_p020_21.png] view at source ↗
Figure 22
Figure 22. Figure 22: FIG. 22. Same as Fig. 21, but for the [PITH_FULL_IMAGE:figures/full_fig_p021_22.png] view at source ↗
Figure 23
Figure 23. Figure 23: FIG. 23. Ray-traced images of the ( [PITH_FULL_IMAGE:figures/full_fig_p021_23.png] view at source ↗
read the original abstract

Modified black holes and black hole mimickers can give rise to additional photon rings in ray-traced images. With the photon ring structure of Kerr well understood, the question arises how well future versions of the Event Horizon Telescope images would be able to constrain the presence of non-Kerr photon rings. In this work, we investigate how likely additional photon rings are to present themselves through low-frequency modulations of the visibility amplitude, i.e. in Fourier space where the data live. To this end, we generate ray-traced images of stable and unstable ultracompact, solitonic boson stars, both in spherical symmetry and with rotation. We find that clear modulations in the associated visibility amplitude are only present in spherical symmetry, for a restricted range of observer inclinations, hence suggesting that these modulations can not be a generic expectation of ultracompact black-hole mimickers. Additionally, we discuss how the photon rings are incomplete for the rotating boson stars considered, and how an unstable prograde light ring may be needed to remedy this.

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 / 1 minor

Summary. The manuscript uses numerical ray tracing to generate images of stable and unstable ultracompact solitonic boson stars, both spherically symmetric and rotating. It reports that clear low-frequency modulations in visibility amplitude (indicative of additional photon rings) appear only in the spherical cases and only for a restricted range of observer inclinations. The work concludes that such modulations cannot be viewed as a generic signature of ultracompact black-hole mimickers. It further observes that photon rings remain incomplete in the rotating models and suggests that an unstable prograde light ring may be required to produce complete rings.

Significance. If the numerical findings hold, the result indicates that visibility modulations are unlikely to serve as a robust, model-independent probe of extra photon rings in EHT data, thereby limiting one proposed avenue for constraining non-Kerr ultracompact objects. The paper supplies direct ray-traced images and visibility curves for both stable and unstable boson-star solutions, together with an explicit discussion of photon-ring incompleteness in the rotating sector; these concrete examples constitute a useful addition to the literature on mimicker phenomenology.

major comments (2)
  1. [Abstract] Abstract: the statement that modulations 'can not be a generic expectation of ultracompact black-hole mimickers' is drawn exclusively from the absence of clear modulations in the rotating solitonic boson-star models examined. No cross-comparison with other mimicker families (e.g., gravastars, wormholes, or different scalar potentials) is presented, so the generality claim rests on the untested assumption that the light-ring structure of these specific solutions is representative.
  2. [Discussion] Discussion section on rotating models: the suggestion that 'an unstable prograde light ring may be needed to remedy' photon-ring incompleteness is offered without a quantitative demonstration that adding such a ring in the examined spacetimes would in fact restore completeness; the claim therefore functions as a conjecture rather than a result directly supported by the ray-tracing data.
minor comments (1)
  1. [Abstract / Introduction] The abstract and introduction should state the specific compactness values, scalar-field potential parameters, and rotation rates of the boson-star models so that the numerical results can be reproduced or extended by other groups.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful reading of our manuscript and the constructive comments. We address each major comment below, indicating where revisions will be made to the text.

read point-by-point responses

  1. Referee: [Abstract] Abstract: the statement that modulations 'can not be a generic expectation of ultracompact black-hole mimickers' is drawn exclusively from the absence of clear modulations in the rotating solitonic boson-star models examined. No cross-comparison with other mimicker families (e.g., gravastars, wormholes, or different scalar potentials) is presented, so the generality claim rests on the untested assumption that the light-ring structure of these specific solutions is representative.

    Authors: We agree that the original wording in the abstract is too broad. Our conclusions are drawn from the specific class of ultracompact solitonic boson stars (both spherical and rotating) that we have ray-traced. While these solutions are standard examples of black-hole mimickers possessing multiple light rings, we have not examined other families. We will revise the abstract to qualify the statement as applying to the boson-star models considered in this work. revision: yes

  2. Referee: [Discussion] Discussion section on rotating models: the suggestion that 'an unstable prograde light ring may be needed to remedy' photon-ring incompleteness is offered without a quantitative demonstration that adding such a ring in the examined spacetimes would in fact restore completeness; the claim therefore functions as a conjecture rather than a result directly supported by the ray-tracing data.

    Authors: The referee correctly identifies that this is a conjecture motivated by the light-ring structure observed in our models and by comparison with the spherical cases and Kerr, rather than a direct numerical test of modifying the spacetime. We will revise the discussion section to present the statement explicitly as a conjecture and will adjust the language to avoid implying a demonstrated result. revision: partial

Circularity Check

0 steps flagged

No significant circularity detected

full rationale

The paper's central results are obtained via direct numerical ray-tracing of specific stable/unstable solitonic boson star solutions to the Einstein-Klein-Gordon system. The claim that visibility modulations are not generic follows from the absence of such modulations in the examined rotating cases, without any self-referential definitions, fitted parameters renamed as predictions, or load-bearing self-citations. No equations reduce to their inputs by construction, and the derivation chain consists of independent numerical outputs rather than tautological mappings. The representativeness concern is a scope limitation, not a circularity violation under the enumerated patterns.

Axiom & Free-Parameter Ledger

1 free parameters · 2 axioms · 0 invented entities

Based on abstract only; the work relies on standard general relativity and specific choices of boson star models with no new entities postulated.

free parameters (1)
  • boson star model parameters (compactness, scalar field potential, rotation rate)
    Specific ultracompact configurations are selected for the ray tracing; exact values not stated in abstract.
axioms (2)
  • standard math Spacetime around the boson stars is governed by general relativity
    Implicit foundation for all ray tracing in the paper.
  • domain assumption Ultracompact solitonic boson stars can exist in both stable and unstable configurations
    The paper explicitly considers both classes of models.

pith-pipeline@v0.9.1-grok · 5714 in / 1259 out tokens · 52631 ms · 2026-07-01T02:08:17.122180+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

142 extracted references · 104 canonical work pages

  1. [1]

    The visibility amplitudes for near-equatorial ob- servers can display a notable low-frequency mod- ulation on long baselines

  2. [2]

    This low-frequency modulation is present, despite the asymmetry in the image as a result of the fluid velocity

  3. [3]

    This could be due to the larger separation between the photon ring pairs, and the stronger decay of the signal towards longer base- lines

    Observers close to the symmetry axis (perpendicu- lar to the accretion plane) still see highly circular photon rings, but no strong modulations in the to- tal VA are apparent. This could be due to the larger separation between the photon ring pairs, and the stronger decay of the signal towards longer base- lines

  4. [4]

    This appears to violate the simple picture used to derive the mod- ulations

    Observers at intermediate angles are less likely to see modulations, as the photon rings are less circu- lar and have varying separation. This appears to violate the simple picture used to derive the mod- ulations

  5. [5]

    We reiterate that we have focussed on the first-order photon ring(s), i.e

    Despite not having LRs, some BSs just outside of the ultracompact regime can still source modula- tions as they are still sufficiently compact to gen- erate a finite number of photon rings. We reiterate that we have focussed on the first-order photon ring(s), i.e. those sourced by geodesics that pass through the accretion disc twice. The above conclusions...

  6. [6]

    In this context, nearly bound means that the conserved quantitiesE=−p t, L=p ϕ of the geodesic are approximately those associated with the LR, which we denote asE u, Lu

    Spherical symmetry Consider a nearly-bound null geodesic in the equato- rial plane, starting close to the unstable LR at radial coordinater 0 =r u +δr 0 withδr 0 ≪r u LR (and WLOG we can assumeϕ 0 = 0). In this context, nearly bound means that the conserved quantitiesE=−p t, L=p ϕ of the geodesic are approximately those associated with the LR, which we de...

  7. [7]

    Due to the reflection symmetry with 17 respect to the equatorial plane, a nearly-bound geodesic that has an initial velocity in the equatorial plane will remain there22

    Rotating BS We follow a similar approach to calculate the Lyapunov exponent associated with the unstable LR in the rotat- ing BS spacetimes. Due to the reflection symmetry with 17 respect to the equatorial plane, a nearly-bound geodesic that has an initial velocity in the equatorial plane will remain there22. Calculating the Lyapunov exponent as- sociated...

  8. [8]

    (bottom) We plot the absolute differences between the simulations at different resolution, i.e

    a low-resolution simulation, capped at 5×10 5 geodesics, 2) the same simulation without a cap on the number of geodesics and 3) a simulation with doubled resolution, capped at 2×106 geodesics. (bottom) We plot the absolute differences between the simulations at different resolution, i.e. adding a sublevel, and the difference between the low-resolution sim...

  9. [9]

    Black hole mimickers: from theory to observation

    Cosimo Bambi et al. Black hole mimickers: from theory to observation. 5 2025

    2025

  10. [10]

    Testing the nature of dark compact objects: a status report.Living Rev

    Vitor Cardoso and Paolo Pani. Testing the nature of dark compact objects: a status report.Living Rev. Rel., 22(1):4, 2019. doi:10.1007/s41114-019-0020-4

    work page doi:10.1007/s41114-019-0020-4 2019

  11. [11]

    Springer Nature Singapore, Singa- pore, 2025

    Miguel Bezares and Nicolas Sanchis-Gual.Exotic Com- 22 pact Objects: A Recent Numerical-Relativity Perspec- tive, pages 619–661. Springer Nature Singapore, Singa- pore, 2025. doi:10.1007/978-981-97-8522-3˙18

    work page doi:10.1007/978-981-97-8522-3 2025

  12. [12]

    David J. Kaup. Klein-Gordon Geon.Phys. Rev., 172: 1331–1342, 1968. doi:10.1103/PhysRev.172.1331

    work page doi:10.1103/physrev.172.1331 1968

  13. [13]

    Systems of self- gravitating particles in general relativity and the con- cept of an equation of state.Phys

    Remo Ruffini and Silvano Bonazzola. Systems of self- gravitating particles in general relativity and the con- cept of an equation of state.Phys. Rev., 187:1767–1783,

  14. [14]

    doi:10.1103/PhysRev.187.1767

    work page doi:10.1103/physrev.187.1767

  15. [15]

    Friedberg, T

    R. Friedberg, T. D. Lee, and Y. Pang. Scalar Soliton Stars and Black Holes.Phys. Rev. D, 35:3658, 1987. doi:10.1103/PhysRevD.35.3658

    work page doi:10.1103/physrevd.35.3658 1987

  16. [16]

    Rotat- ing boson stars and Q-balls.Phys

    Burkhard Kleihaus, Jutta Kunz, and Meike List. Rotat- ing boson stars and Q-balls.Phys. Rev. D, 72:064002,

  17. [17]

    doi:10.1103/PhysRevD.72.064002

    work page doi:10.1103/physrevd.72.064002

  18. [18]

    Liebling and Carlos Palenzuela

    Steven L. Liebling and Carlos Palenzuela. Dynami- cal boson stars.Living Rev. Rel., 26(1):1, 2023. doi: 10.1007/s41114-023-00043-4

    work page doi:10.1007/s41114-023-00043-4 2023

  19. [19]

    Boson stars and oscillatons: A re- view.Int

    Luca Visinelli. Boson stars and oscillatons: A re- view.Int. J. Mod. Phys. D, 30(15):2130006, 2021. doi: 10.1142/S0218271821300068

    work page doi:10.1142/s0218271821300068 2021

  20. [20]

    T. D. Lee and Yang Pang. Stability of Mini - Boson Stars.Nucl. Phys. B, 315:477, 1989. doi:10.1016/0550- 3213(89)90365-9

    work page doi:10.1016/0550- 1989

  21. [21]

    Gravitational Stability of Scalar Matter.Nucl

    Marcelo Gleiser and Richard Watkins. Gravitational Stability of Scalar Matter.Nucl. Phys. B, 319:733–746,

  22. [22]

    doi:10.1016/0550-3213(89)90627-5

    work page doi:10.1016/0550-3213(89)90627-5

  23. [23]

    Font, and Eugen Radu

    Fabrizio Di Giovanni, Nicolas Sanchis-Gual, Pablo Cerd´ a-Dur´ an, Miguel Zilh˜ ao, Carlos Herdeiro, Jos´ e A. Font, and Eugen Radu. Dynamical bar-mode instabil- ity in spinning bosonic stars.Phys. Rev. D, 102(12): 124009, 2020. doi:10.1103/PhysRevD.102.124009

    work page doi:10.1103/physrevd.102.124009 2020

  24. [24]

    Nils Siemonsen and William E. East. Stability of rotating scalar boson stars with nonlinear interac- tions.Phys. Rev. D, 103(4):044022, 2021. doi: 10.1103/PhysRevD.103.044022

    work page doi:10.1103/physrevd.103.044022 2021

  25. [25]

    Sanchis-Gual, F

    N. Sanchis-Gual, F. Di Giovanni, M. Zilh˜ ao, C. Herdeiro, P. Cerd´ a-Dur´ an, J. A. Font, and E. Radu. Nonlinear Dynamics of Spinning Bosonic Stars: For- mation and Stability.Phys. Rev. Lett., 123(22):221101,

  26. [26]

    doi:10.1103/PhysRevLett.123.221101

    work page doi:10.1103/physrevlett.123.221101

  27. [27]

    Self-interactions can stabilize excited boson stars.Class

    Nicolas Sanchis-Gual, Carlos Herdeiro, and Eugen Radu. Self-interactions can stabilize excited boson stars.Class. Quant. Grav., 39(6):064001, 2022. doi: 10.1088/1361-6382/ac4b9b

    work page doi:10.1088/1361-6382/ac4b9b 2022

  28. [28]

    Stability and col- lisions of excited spherical boson stars: Glimpses of chains and rings.Phys

    Marco Brito, Carlos Herdeiro, Eugen Radu, Nicolas Sanchis-Gual, and Miguel Zilh˜ ao. Stability and col- lisions of excited spherical boson stars: Glimpses of chains and rings.Phys. Rev. D, 113(2):024008, 2026. doi:10.1103/8bwz-wqhp

    work page doi:10.1103/8bwz-wqhp 2026

  29. [29]

    Perturbations of Solitonic Bo- son Stars: Nonlinear Radial Stability and Binding En- ergy.J

    Gareth Arturo Marks. Perturbations of Solitonic Bo- son Stars: Nonlinear Radial Stability and Binding En- ergy.J. Phys. Conf. Ser., 3177(1):012047, 2026. doi: 10.1088/1742-6596/3177/1/012047

    work page doi:10.1088/1742-6596/3177/1/012047 2026

  30. [30]

    Boson stars inD≥4 dimensions: stability, oscillation frequencies, and dynamical evolutions.Class

    Gareth Arturo Marks and Abdullah Al Zaif. Boson stars inD≥4 dimensions: stability, oscillation frequencies, and dynamical evolutions.Class. Quant. Grav., 43(8): 085014, 2026. doi:10.1088/1361-6382/ae60bc

    work page doi:10.1088/1361-6382/ae60bc 2026

  31. [31]

    Palenzuela, I

    C. Palenzuela, I. Olabarrieta, L. Lehner, and Steven L. Liebling. Head-on collisions of boson stars.Phys. Rev. D, 75:064005, 2007. doi:10.1103/PhysRevD.75.064005

    work page doi:10.1103/physrevd.75.064005 2007

  32. [32]

    Gravita- tional Wave Signatures of Highly Compact Boson Star Binaries.Phys

    Carlos Palenzuela, Paolo Pani, Miguel Bezares, Vitor Cardoso, Luis Lehner, and Steven Liebling. Gravita- tional Wave Signatures of Highly Compact Boson Star Binaries.Phys. Rev. D, 96(10):104058, 2017. doi: 10.1103/PhysRevD.96.104058

    work page doi:10.1103/physrevd.96.104058 2017

  33. [33]

    Final fate of compact boson star mergers.Phys

    Miguel Bezares, Carlos Palenzuela, and Carles Bona. Final fate of compact boson star mergers.Phys. Rev. D, 95(12):124005, 2017. doi:10.1103/PhysRevD.95.124005

    work page doi:10.1103/physrevd.95.124005 2017

  34. [35]

    Grav- itational waves and kicks from the merger of unequal mass, highly compact boson stars.Phys

    Miguel Bezares, Mateja Boˇ skovi´ c, Steven Liebling, Car- los Palenzuela, Paolo Pani, and Enrico Barausse. Grav- itational waves and kicks from the merger of unequal mass, highly compact boson stars.Phys. Rev. D, 105 (6):064067, 2022. doi:10.1103/PhysRevD.105.064067

    work page doi:10.1103/physrevd.105.064067 2022

  35. [36]

    Thomas Helfer, Ulrich Sperhake, Robin Croft, Miren Radia, Bo-Xuan Ge, and Eugene A. Lim. Malaise and remedy of binary boson-star initial data.Class. Quant. Grav., 39(7):074001, 2022. doi:10.1088/1361- 6382/ac53b7

    work page doi:10.1088/1361- 2022

  36. [37]

    Font, Samson H

    Nicolas Sanchis-Gual, Juan Calder´ on Bustillo, Carlos Herdeiro, Eugen Radu, Jos´ e A. Font, Samson H. W. Leong, and Alejandro Torres-Forn´ e. Impact of the wave- like nature of Proca stars on their gravitational-wave emission.Phys. Rev. D, 106(12):124011, 2022. doi: 10.1103/PhysRevD.106.124011

    work page doi:10.1103/physrevd.106.124011 2022

  37. [38]

    Nils Siemonsen and William E. East. Generic initial data for binary boson stars.Phys. Rev. D, 108(12): 124015, 2023. doi:10.1103/PhysRevD.108.124015

    work page doi:10.1103/physrevd.108.124015 2023

  38. [39]

    Nils Siemonsen and William E. East. Binary boson stars: Merger dynamics and formation of rotating rem- nant stars.Phys. Rev. D, 107(12):124018, 2023. doi: 10.1103/PhysRevD.107.124018

    work page doi:10.1103/physrevd.107.124018 2023

  39. [40]

    Tamara Evstafyeva, Ulrich Sperhake, Thomas Helfer, Robin Croft, Miren Radia, Bo-Xuan Ge, and Eugene A. Lim. Unequal-mass boson-star binaries: initial data and merger dynamics.Class. Quant. Grav., 40(8):085009,

  40. [41]

    doi:10.1088/1361-6382/acc2a8

    work page doi:10.1088/1361-6382/acc2a8

  41. [42]

    Romero-Shaw, and Michalis Agathos

    Tamara Evstafyeva, Ulrich Sperhake, Isobel M. Romero-Shaw, and Michalis Agathos. Gravitational- Wave Data Analysis with High-Precision Numer- ical Relativity Simulations of Boson Star Merg- ers.Phys. Rev. Lett., 133(13):131401, 2024. doi: 10.1103/PhysRevLett.133.131401

    work page doi:10.1103/physrevlett.133.131401 2024

  42. [43]

    Lim, Ulrich Sperhake, Tamara Evstafyeva, Daniela Cors, Eloy de Jong, Robin Croft, and Thomas Helfer

    Bo-Xuan Ge, Eugene A. Lim, Ulrich Sperhake, Tamara Evstafyeva, Daniela Cors, Eloy de Jong, Robin Croft, and Thomas Helfer. Dynamics and gravitational radi- ation of stable and unstable boson-star mergers.Phys. Rev. D, 112(12):124080, 2025. doi:10.1103/2dhs-phl4

    work page doi:10.1103/2dhs-phl4 2025

  43. [44]

    Moore, and Tamanna Jain

    Tamara Evstafyeva, Antonia Seifert, Ulrich Sperhake, Christopher J. Moore, and Tamanna Jain. Lessons from binary dynamics of inspiralling equal-mass boson-star mergers. 4 2026

    2026

  44. [45]

    Niemeyer

    Katy Clough, Tim Dietrich, and Jens C. Niemeyer. Ax- ion star collisions with black holes and neutron stars in full 3D numerical relativity.Phys. Rev. D, 98(8):083020,

  45. [46]

    doi:10.1103/PhysRevD.98.083020

    work page doi:10.1103/physrevd.98.083020

  46. [47]

    Piercing of a boson star by a black hole.Phys

    Vitor Cardoso, Taishi Ikeda, Zhen Zhong, and Miguel Zilh˜ ao. Piercing of a boson star by a black hole.Phys. Rev. D, 106(4):044030, 2022. doi: 10.1103/PhysRevD.106.044030

    work page doi:10.1103/physrevd.106.044030 2022

  47. [48]

    Piercing of a solitonic boson star by a black hole.Phys

    Zhen Zhong, Vitor Cardoso, Taishi Ikeda, and Miguel Zilh˜ ao. Piercing of a solitonic boson star by a black hole.Phys. Rev. D, 108(8):084051, 2023. doi: 10.1103/PhysRevD.108.084051. 23

    work page doi:10.1103/physrevd.108.084051 2023

  48. [49]

    Staelens, and Ulrich Sperhake

    Gareth Arturo Marks, Seppe J. Staelens, and Ulrich Sperhake. Black Hole-Boson Star Binaries: Gravita- tional Wave Signals and Tidal Disruption. 4 2026

    2026

  49. [50]

    Boson star-black hole binaries: initial data and head-on collisions

    Zhuan Ning. Boson star-black hole binaries: initial data and head-on collisions. 4 2026

    2026

  50. [51]

    Yoshida, Y

    S. Yoshida, Y. Eriguchi, and T. Futamase. Quasinormal modes of boson stars.Phys. Rev. D, 50:6235–6246, 1994. doi:10.1103/PhysRevD.50.6235

    work page doi:10.1103/physrevd.50.6235 1994

  51. [52]

    Caio F. B. Macedo, Paolo Pani, Vitor Cardoso, and Lu´ ıs C. B. Crispino. Astrophysical signatures of boson stars: quasinormal modes and inspiral reso- nances.Phys. Rev. D, 88(6):064046, 2013. doi: 10.1103/PhysRevD.88.064046

    work page doi:10.1103/physrevd.88.064046 2013

  52. [53]

    Nonlinear Treatment of a Black Hole Mimicker Ringdown.Phys

    Nils Siemonsen. Nonlinear Treatment of a Black Hole Mimicker Ringdown.Phys. Rev. Lett., 133(3):031401,

  53. [54]

    doi:10.1103/PhysRevLett.133.031401

    work page doi:10.1103/physrevlett.133.031401

  54. [55]

    Gravitational scattering of solitonic boson stars: Ana- lytics vs Numerics

    Thibault Damour, Tamanna Jain, and Ulrich Sperhake. Gravitational scattering of solitonic boson stars: Ana- lytics vs Numerics. 11 2025

    2025

  55. [56]

    Torres, S

    Diego F. Torres, S. Capozziello, and G. Lambiase. A Su- permassive scalar star at the galactic center?Phys. Rev. D, 62:104012, 2000. doi:10.1103/PhysRevD.62.104012

    work page doi:10.1103/physrevd.62.104012 2000

  56. [57]

    Siddhartha Guzman

    F. Siddhartha Guzman. Accretion disc onto boson stars: A Way to supplant black holes candidates.Phys. Rev. D, 73:021501, 2006. doi:10.1103/PhysRevD.73.021501

    work page doi:10.1103/physrevd.73.021501 2006

  57. [58]

    Constraining scalar fields with stellar kinematics and collisional dark matter.JCAP, 11:002,

    Pau Amaro-Seoane, Juan Barranco, Argelia Bernal, and Luciano Rezzolla. Constraining scalar fields with stellar kinematics and collisional dark matter.JCAP, 11:002,

  58. [59]

    doi:10.1088/1475-7516/2010/11/002

    work page doi:10.1088/1475-7516/2010/11/002 2010

  59. [60]

    Pedro V. P. Cunha, Emanuele Berti, and Carlos A. R. Herdeiro. Light-Ring Stability for Ultracompact Ob- jects.Phys. Rev. Lett., 119(25):251102, 2017. doi: 10.1103/PhysRevLett.119.251102

    work page doi:10.1103/physrevlett.119.251102 2017

  60. [61]

    Pedro V. P. Cunha, Carlos Herdeiro, Eugen Radu, and Nicolas Sanchis-Gual. Exotic Compact Objects and the Fate of the Light-Ring Instability.Phys. Rev. Lett., 130 (6):061401, 2023. doi:10.1103/PhysRevLett.130.061401

    work page doi:10.1103/physrevlett.130.061401 2023

  61. [62]

    Staelens, Tamara Evstafyeva, and Ulrich Sperhake

    Gareth Arturo Marks, Seppe J. Staelens, Tamara Evstafyeva, and Ulrich Sperhake. Long-Term Stable Nonlinear Evolutions of Ultracompact Black-Hole Mim- ickers.Phys. Rev. Lett., 135(13):131402, 2025. doi: 10.1103/lk48-7r2f

    work page doi:10.1103/lk48-7r2f 2025

  62. [63]

    When do neural networks outperform kernel methods?*

    Seppe J. Staelens. Search for growing angular modes in ultracompact boson star evolutions.J. Phys. Conf. Ser., 3177(1):012046, 2026. doi:10.1088/1742- 6596/3177/1/012046

    work page doi:10.1088/1742- 2026

  63. [64]

    Tamara Evstafyeva, Nils Siemonsen, and William E. East. Assessing the stability of ultracompact spinning boson stars with nonlinear evolutions.Phys. Rev. D, 113(4):044024, 2026. doi:10.1103/2vz3-s39r

    work page doi:10.1103/2vz3-s39r 2026

  64. [65]

    Friedman

    John L. Friedman. Ergosphere instability.Com- mun. Math. Phys., 63(3):243–255, 1978. doi: 10.1007/BF01196933

    work page doi:10.1007/bf01196933 1978

  65. [66]

    Parton Fragmen- tation and String Dynamics,

    A. Vilenkin. Exponential Amplification of Waves in the Gravitational Field of Ultrarelativistic Rotating Body. Phys. Lett. B, 78:301–303, 1978. doi:10.1016/0370- 2693(78)90027-8

    work page doi:10.1016/0370- 1978

  66. [67]

    A Proof of Friedman’s Ergosphere Instability for Scalar Waves.Commun

    Georgios Moschidis. A Proof of Friedman’s Ergosphere Instability for Scalar Waves.Commun. Math. Phys., 358(2):437–520, 2018. doi:10.1007/s00220-017-3010-y

    work page doi:10.1007/s00220-017-3010-y 2018

  67. [68]

    Weakly Turbulent Saturation of the Nonlinear Scalar Ergoregion Instability.Phys

    Nils Siemonsen. Weakly Turbulent Saturation of the Nonlinear Scalar Ergoregion Instability.Phys. Rev. Lett., 136(17):171401, 2026. doi:10.1103/ytqg-v1j8

    work page doi:10.1103/ytqg-v1j8 2026

  68. [69]

    Ergoregion instability in bosonic stars: Scalar mode structure, universality, and weakly nonlin- ear effects.Phys

    Nils Siemonsen. Ergoregion instability in bosonic stars: Scalar mode structure, universality, and weakly nonlin- ear effects.Phys. Rev. D, 112(12):124031, 2025. doi: 10.1103/sbtt-jnjg

    work page doi:10.1103/sbtt-jnjg 2025

  69. [70]

    Nils Siemonsen and William E. East. Nonlinear evolu- tion of the ergoregion instability: Turbulence, bursts of radiation, and black hole formation. 12 2025

    2025

  70. [71]

    Akiyamam and others (Event Horizon Telescope Collaboration) ,\ https://doi.org/10.3847/2041-8213/ab0ec7 journal journal Astrophys

    Kazunori Akiyama et al. First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole.Astrophys. J. Lett., 875:L1, 2019. doi: 10.3847/2041-8213/ab0ec7

    work page doi:10.3847/2041-8213/ab0ec7 2019

  71. [72]

    Menci, M

    Kazunori Akiyama et al. First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Su- permassive Black Hole in the Center of the Milky Way. Astrophys. J. Lett., 930(2):L12, 2022. doi:10.3847/2041- 8213/ac6674

    work page doi:10.3847/2041- 2022

  72. [73]

    Vincent, and Vitor Cardoso

    Jo˜ ao Lu´ ıs Rosa, Paulo Garcia, Fr´ ed´ eric H. Vincent, and Vitor Cardoso. Observational signatures of hot spots or- biting horizonless objects.Phys. Rev. D, 106(4):044031,

  73. [74]

    doi:10.1103/PhysRevD.106.044031

    work page doi:10.1103/physrevd.106.044031

  74. [75]

    Polarimetry imprints of exotic compact objects: Soli- tonic boson stars.Phys

    Jo˜ ao Lu´ ıs Rosa, Nicolas Aimar, and Hanna Liis Tamm. Polarimetry imprints of exotic compact objects: Soli- tonic boson stars.Phys. Rev. D, 111(12):124036, 2025. doi:10.1103/h8ln-psjr

    work page doi:10.1103/h8ln-psjr 2025

  75. [76]

    Jo˜ ao Lu´ ıs Rosa, Caio F. B. Macedo, and Diego Rubiera- Garcia. Imaging compact boson stars with hot spots and thin accretion disks.Phys. Rev. D, 108(4):044021, 2023. doi:10.1103/PhysRevD.108.044021

    work page doi:10.1103/physrevd.108.044021 2023

  76. [77]

    Observational features of massive boson stars with thin disk accretion.Phys

    Guo-Ping Li, Meng-Qi Wu, Ke-Jian He, and Qing-Quan Jiang. Observational features of massive boson stars with thin disk accretion.Phys. Rev. D, 113(4):043009,

  77. [78]

    doi:10.1103/yq27-3z22

    work page doi:10.1103/yq27-3z22

  78. [79]

    Optical images of massive boson stars with nonlinear electrodynamics.Eur

    Xiao-Xiong Zeng, Huan Ye, Ke-Jian He, and Hao Yu. Optical images of massive boson stars with nonlinear electrodynamics.Eur. Phys. J. C, 85(10):1211, 2025. doi:10.1140/epjc/s10052-025-14983-4

    work page doi:10.1140/epjc/s10052-025-14983-4 2025

  79. [80]

    Polarization images of solitonic boson stars.Eur

    Xiao-Xiong Zeng, Chen-Yu Yang, Hao Yu, and Ke-Jian He. Polarization images of solitonic boson stars.Eur. Phys. J. C, 86(2):169, 2026. doi:10.1140/epjc/s10052- 026-15373-0

    work page doi:10.1140/epjc/s10052- 2026

  80. [81]

    Broadened Lensing Rings of Compact Bo- son Stars: Enhanced Imprint of Accretion Flow in Im- ages and Visibilities

    Xiangyu Wang, Xinyu Wang, Minyong Guo, and Hai- Qing Zhang. Broadened Lensing Rings of Compact Bo- son Stars: Enhanced Imprint of Accretion Flow in Im- ages and Visibilities. 6 2026

    2026

Showing first 80 references.