pith. sign in

arxiv: 2605.14728 · v1 · pith:C7TBAQX5new · submitted 2026-05-14 · 🌀 gr-qc · astro-ph.HE

Wide parameter-space O3 search for continuous gravitational waves from unknown neutron stars in binary systems

P. B. Covas , M. A. Papa , R. Prix This is my paper

Pith reviewed 2026-06-30 20:32 UTC · model grok-4.3

classification 🌀 gr-qc astro-ph.HE
keywords continuous gravitational wavesneutron starsbinary systemsLIGO O3upper limitsellipticityr-modesgravitational wave searches
0
0 comments X

The pith

No continuous gravitational wave signals from unknown binary neutron stars detected in O3 data, setting new upper limits on amplitudes.

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

This paper reports on a comprehensive search for continuous gravitational waves from unknown neutron stars in binary systems using LIGO O3 data. It covers a wide range of gravitational-wave frequencies from 50 to 1000 Hz and orbital periods shorter than 3 days for the first time with advanced detectors. No signals are found, allowing the authors to place the most stringent constraints to date on the possible amplitudes of such signals. These results are important because binary systems are common among fast-spinning pulsars, and accretion in binaries can create the asymmetry needed for gravitational wave emission. A sympathetic reader would care because it narrows down the properties neutron stars must have if they are to produce detectable continuous waves.

Core claim

The search of the O3 dataset finds no evidence for continuous gravitational waves from unknown neutron stars in binary systems. It excludes with 95% confidence that neutron stars within 100 pc rotating faster than approximately 495 Hz have ellipticities above 5.2 × 10^{-8}. Similarly, it excludes r-mode amplitudes above 1.5 × 10^{-6} for stars rotating faster than approximately 740 Hz within the same distance.

What carries the argument

The matched-filtering search over a large template bank covering frequency, frequency derivative, and binary orbital parameters.

Load-bearing premise

The template bank and analysis pipeline are complete enough to detect any signal above the reported amplitude thresholds without significant losses from approximations or data quality issues.

What would settle it

A confirmed detection of a continuous gravitational wave from a neutron star in a binary system within 100 pc, with rotation frequency above 495 Hz and ellipticity exceeding 5.2×10^{-8}, would contradict the exclusion limits.

Figures

Figures reproduced from arXiv: 2605.14728 by M. A. Papa, P. B. Covas, R. Prix.

Figure 1
Figure 1. Figure 1: The black boxes show the signal-parameter regions covered by this search (left plot shows {Porb, ap}, right plot shows {Porb, ν0}). The circles show the known pulsars in binary systems from the ATNF catalog version 2.6.3 (Manchester et al. 2005) and the color encodes ν0 (left plot) and ap (right plot). The dashed boxes show the ranges covered by previous searches using O3 or O4 Advanced LIGO data. The diff… view at source ↗
Figure 2
Figure 2. Figure 2: Square root of the harmonic mean power spectral density √ Sn of the data used in this search as a function of frequency. The upper blue curve shows H1, the middle green curve shows H1+L1, and the lower orange curve shows L1. (Manchester et al. 2005) have eccentricities outside of the range defined by equations (2) and (3). 2.3. Initial search We use the BinarySkyHouF (Covas & Prix 2022a) semi-coherent sear… view at source ↗
Figure 3
Figure 3. Figure 3: Maximum significance s0 of the initial stage in each 0.1 Hz frequency band as a function of the gravitation￾al-wave frequency. The black lines show the threshold to consider a band non-Gaussian. A few bands with negative maximum s0 values are not shown on the plot. ceptance/rejection regions in the s0 − s1 and s0 − log10 Bˆ 1;S/GLtL planes for the candidates. Our criteria has a false dismissal probability … view at source ↗
Figure 4
Figure 4. Figure 4: Distribution of significance values s1 (left plot) and log10 Bˆ 1;S/GLtL (right plot) for the follow-up. In the right plot we use a “symlog” scale, i.e., linear between -1 and 1. The blue circles show the 7 200 simulated test-signals, and the crosses indicate the 127 500 search candidates, with the green crosses marking candidates that pass the vetoes. The region below the black line is the candidate-rejec… view at source ↗
Figure 5
Figure 5. Figure 5: Estimated upper limits on the gravitational-wave amplitude h 95% 0 (left plot), on the neutron star ellipticity ϵ (upper right plot), and on the r-mode amplitude α (lower right plot) at the 95% confidence level as a function of the gravitational-wave frequency. Left plot: the black curve shows the results from this search, with the areas surrounding it indicating the 1σ and 2σ uncertainty regions. The othe… view at source ↗
Figure 6
Figure 6. Figure 6: Mismatch distribution of this search at two differ￾ent frequencies, in the 200 Hz and 800 Hz region, respectively. The other parameters that describe the CW signal span the ranges given in table 1. The legend shows the mean of each distribution for each different region of orbital parameter-s￾pace. A. INITIAL STAGE SET-UP DETAILS The mismatch distributions for the various orbital pa￾rameter regions at two … view at source ↗
Figure 8
Figure 8. Figure 8: Illustrative example of the detection probability as a function of the normalized inverse signal-amplitude (D) for signals at ≈ 803.4 Hz and with orbital parameters from region A. The top axis shows the corresponding values of the signal amplitude (h0). The error bars show the 1σ un￾certainty, and the star marker shows the interpolated value of D 95%. REFERENCES Aasi, J., Abbott, B. P., Abbott, R., et al. … view at source ↗
read the original abstract

Continuous gravitational waves, i.e., persistent and nearly-monochromatic signals emitted by asymmetric spinning neutron stars, remain elusive. Searches for these signals from unknown binary systems are the most computationally challenging, but they are essential, given that binary accretion provides a natural mechanism for creating the required asymmetry, and around half of the known pulsars rotating above 25 Hz are part of a binary system. Here we report on a search of a large uncharted parameter-space region: for the first time we cover gravitational-wave frequencies above 520 Hz (from 50 to 1000 Hz), and, for the first time with advanced detectors, orbital periods lower than 3 days are explored. No signal is detected, and we set the most stringent constraints to date on the amplitude of signals of this kind. Our results exclude with $95\%$ confidence neutron stars within 100 pc and rotating faster than $\sim$ 495 Hz from having ellipticities above $5.2 \times 10^{-8}$. Within the same distance our results also exclude r-mode amplitudes above $1.5 \times 10^{-6}$ for stars rotating faster than $\sim$ 740 Hz.

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

1 major / 0 minor

Summary. The manuscript reports results from a wide parameter-space search for continuous gravitational waves from unknown neutron stars in binary systems using LIGO O3 data. It covers gravitational-wave frequencies from 50 to 1000 Hz and, for the first time with advanced detectors, orbital periods shorter than 3 days. No signals are detected. The authors set the most stringent constraints to date, excluding with 95% confidence neutron stars within 100 pc rotating faster than ~495 Hz from having ellipticities above 5.2×10^{-8}, and excluding r-mode amplitudes above 1.5×10^{-6} for stars rotating faster than ~740 Hz.

Significance. If the search completeness and sensitivity are validated, the work provides the tightest limits to date on continuous-wave signals from binary neutron stars by extending coverage into previously unexplored high-frequency and short-orbital-period regimes. This is valuable for constraining neutron-star asymmetries and accretion mechanisms. The computational scope of the search is a notable strength.

major comments (1)
  1. [Results and Methods sections (validation of template bank and sensitivity)] The 95% confidence exclusion limits on ellipticity and r-mode amplitude (stated in the abstract and results) rest on the assumption that the template bank and pipeline are complete and sensitive across the full 50-1000 Hz range and all orbital periods down to <3 days with low mismatch. The manuscript must include explicit validation (e.g., mismatch calculations or recovery fractions from injections) specifically for the newly explored regimes above 520 Hz and below 3-day periods; without this, the robustness of the quoted thresholds cannot be verified and the central claim is not fully supported.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their careful reading of the manuscript and for highlighting the need for explicit validation in the newly explored parameter space. We address the comment below.

read point-by-point responses

  1. Referee: [Results and Methods sections (validation of template bank and sensitivity)] The 95% confidence exclusion limits on ellipticity and r-mode amplitude (stated in the abstract and results) rest on the assumption that the template bank and pipeline are complete and sensitive across the full 50-1000 Hz range and all orbital periods down to <3 days with low mismatch. The manuscript must include explicit validation (e.g., mismatch calculations or recovery fractions from injections) specifically for the newly explored regimes above 520 Hz and below 3-day periods; without this, the robustness of the quoted thresholds cannot be verified and the central claim is not fully supported.

    Authors: We agree that explicit validation for the high-frequency and short-orbital-period regimes is essential to support the quoted limits. Although the Methods section describes the general construction of the template bank with mismatch bounds and the sensitivity estimation procedure, we acknowledge that specific demonstrations for the new regimes (f > 520 Hz and P_orb < 3 days) were not included. In the revised version, we will add a dedicated paragraph or subsection presenting mismatch histograms and injection recovery fractions for representative points in these regimes, confirming that the pipeline performs as designed. revision: yes

Circularity Check

0 steps flagged

Observational matched-filter search yields data-driven upper limits with no circular derivation.

full rationale

This is a standard gravitational-wave search paper that applies matched filtering to real LIGO O3 detector data over an expanded parameter space (50-1000 Hz, orbital periods <3 days). The central results—no detected signals and 95% confidence exclusion limits on ellipticity (5.2e-8) and r-mode amplitude (1.5e-6) for d<100 pc—are extracted empirically from the lack of candidates above threshold. No equations, predictions, or uniqueness claims reduce by construction to fitted inputs, self-citations, or ansatzes; the pipeline completeness assumption is an external methodological claim, not a self-referential loop. The derivation chain is self-contained against external data.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

Review based on abstract only; the work rests on standard domain assumptions of gravitational-wave astronomy rather than new postulates.

axioms (2)
  • domain assumption LIGO O3 strain data can be searched for continuous-wave signals via matched filtering after standard noise subtraction and vetoes.
    Standard assumption invoked whenever a continuous-wave search reports upper limits from real detector data.
  • domain assumption Neutron stars in binaries can sustain the ellipticities or r-modes needed to produce detectable continuous gravitational waves.
    Background assumption from general relativity and neutron-star astrophysics used to interpret non-detections as constraints on those quantities.

pith-pipeline@v0.9.1-grok · 5750 in / 1538 out tokens · 58311 ms · 2026-06-30T20:32:22.209491+00:00 · methodology

discussion (0)

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

Forward citations

Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. First Constraints on the Ellipticities of Self-Interacting Fermionic Dark Matter Admixed Neutron Stars from Continuous Gravitational-Wave Searches

    astro-ph.CO 2026-06 unverdicted novelty 7.0

    Using LIGO O3 continuous-wave search data, the authors place the first constraints on ellipticities of self-interacting fermionic dark matter admixed neutron stars and exclude regions of the DM parameter space for mas...

Reference graph

Works this paper leans on

43 extracted references · 42 canonical work pages · cited by 1 Pith paper · 2 internal anchors

  1. [1]

    P., Abbott, R., et al

    Aasi, J., Abbott, B. P., Abbott, R., et al. 2014, Phys. Rev. D, 90, 062010, doi: 10.1103/PhysRevD.90.062010

    work page doi:10.1103/physrevd.90.062010 2014

  2. [2]

    G., Abouelfettouh, I., Acernese, F., et al

    Abac, A. G., Abouelfettouh, I., Acernese, F., et al. 2025, arXiv, 2511.16863, doi: 10.48550/arXiv.2511.16863

    work page doi:10.48550/arxiv.2511.16863 2025

  3. [3]

    2007, Phys

    Abbott, B., Abbott, R., Adhikari, R., et al. 2007, Phys. Rev. D, 76, 042001, doi: 10.1103/PhysRevD.76.042001

    work page doi:10.1103/physrevd.76.042001 2007

  4. [4]

    D., Abraham, S., et al

    Abbott, R., Abbott, T. D., Abraham, S., et al. 2021, Phys. Rev. D, 103, 064017, doi: 10.1103/PhysRevD.103.064017

    work page doi:10.1103/physrevd.103.064017 2021

  5. [5]

    2022, Phys

    Abbott, R., Abe, H., Acernese, F., et al. 2022, Phys. Rev. D, 106, 102008, doi: 10.1103/PhysRevD.106.102008 —. 2023, Astrophys. J. Supplement Series, 267, 29, doi: 10.3847/1538-4365/acdc9f

    work page doi:10.1103/physrevd.106.102008 2022

  6. [6]

    2004, Tech

    Allen, B., & Mendell, G. 2004, Tech. Rep. T040164. https://dcc.ligo.org/LIGO-T040164/public

    2004

  7. [7]

    I., & Prix, R

    Ashton, G., Jones, D. I., & Prix, R. 2015, Phys. Rev. D, 91, 062009, doi: 10.1103/PhysRevD.91.062009

    work page doi:10.1103/physrevd.91.062009 2015

  8. [8]

    Ashton, G., Prix, R., & Jones, D. I. 2017, Phys. Rev. D, 96, 063004, doi: 10.1103/PhysRevD.96.063004

    work page doi:10.1103/physrevd.96.063004 2017

  9. [9]

    D., et al

    Ashton, G., H¨ ubner, M., Lasky, P. D., et al. 2019, Astrophys. J. Supplement Series, 241, 27, doi: 10.3847/1538-4365/ab06fc

    work page doi:10.3847/1538-4365/ab06fc 2019

  10. [10]

    A., & Prix, R

    Behnke, B., Papa, M. A., & Prix, R. 2015, Phys. Rev. D, 91, 064007, doi: 10.1103/PhysRevD.91.064007

    work page doi:10.1103/physrevd.91.064007 2015

  11. [11]

    C., et al

    Biwer, C., Barker, D., Batch, J. C., et al. 2017, Phys. Rev. D, 95, 062002, doi: 10.1103/PhysRevD.95.062002

    work page doi:10.1103/physrevd.95.062002 2017

  12. [12]

    Gravitational waves from pulsars: emission by the magnetic field induced distortion

    Bonazzola, S., & Gourgoulhon, E. 1996, A&A, 312, 675, doi: 10.48550/arXiv.astro-ph/9602107

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.astro-ph/9602107 1996

  13. [13]

    A., & Wasserman, I

    Bondarescu, R., Teukolsky, S. A., & Wasserman, I. 2007, Phys. Rev. D, 76, 064019, doi: 10.1103/PhysRevD.76.064019

    work page doi:10.1103/physrevd.76.064019 2007

  14. [14]

    L., et al

    Buikema, A., Cahillane, C., Mansell, G. L., et al. 2020, Phys. Rev. D, 102, 062003, doi: 10.1103/PhysRevD.102.062003

    work page doi:10.1103/physrevd.102.062003 2020

  15. [15]

    I., Gusakov, M

    Chugunov, A. I., Gusakov, M. E., & Kantor, E. M. 2014, MNRAS, 445, 385, doi: 10.1093/mnras/stu1772

    work page doi:10.1093/mnras/stu1772 2014

  16. [16]

    B., Papa, M

    Covas, P. B., Papa, M. A., & Prix, R. 2025, Astrophys. J., 985, 192, doi: 10.3847/1538-4357/adcc2b —. 2026, https: //www.aei.mpg.de/continuouswaves/O3AllSkyBinary2

    work page doi:10.3847/1538-4357/adcc2b 2025

  17. [17]

    B., Papa, M

    Covas, P. B., Papa, M. A., Prix, R., & Owen, B. J. 2022, Astrophys. J. Lett., 929, L19, doi: 10.3847/2041-8213/ac62d7

    work page doi:10.3847/2041-8213/ac62d7 2022

  18. [18]

    B., & Prix, R

    Covas, P. B., & Prix, R. 2022a, Phys. Rev. D, 106, 084035, doi: 10.1103/PhysRevD.106.084035 —. 2022b, Phys. Rev. D, 105, 124007, doi: 10.1103/PhysRevD.105.124007 10

    work page doi:10.1103/physrevd.106.084035

  19. [19]

    B., Prix, R., & Martins, J

    Covas, P. B., Prix, R., & Martins, J. 2024, Phys. Rev. D, 110, 024053, doi: 10.1103/PhysRevD.110.024053

    work page doi:10.1103/physrevd.110.024053 2024

  20. [20]

    B., & Sintes, A

    Covas, P. B., & Sintes, A. 2020, Phys. Rev. Lett., 124, 191102, doi: 10.1103/PhysRevLett.124.191102

    work page doi:10.1103/physrevlett.124.191102 2020

  21. [21]

    B., & Sintes, A

    Covas, P. B., & Sintes, A. M. 2019, Phys. Rev. D, 99, 124019, doi: 10.1103/PhysRevD.99.124019

    work page doi:10.1103/physrevd.99.124019 2019

  22. [22]

    B., Effler, A., Goetz, E., et al

    Covas, P. B., Effler, A., Goetz, E., et al. 2018, Phys. Rev. D, 97, 082002, doi: 10.1103/PhysRevD.97.082002

    work page doi:10.1103/physrevd.97.082002 2018

  23. [23]

    2018, Phys

    Dreissigacker, C., Prix, R., & Wette, K. 2018, Phys. Rev. D, 98, 084058, doi: 10.1103/PhysRevD.98.084058

    work page doi:10.1103/physrevd.98.084058 2018

  24. [24]

    F., Zdunik, J

    Fantina, A. F., Zdunik, J. L., Chamel, N., et al. 2022, A&A, 665, A74, doi: 10.1051/0004-6361/202243715

    work page doi:10.1051/0004-6361/202243715 2022

  25. [25]

    2019, MNRAS, 488, 99–110, doi: 10.1093/mnras/stz1719 —

    Gittins, F., & Andersson, N. 2019, MNRAS, 488, 99–110, doi: 10.1093/mnras/stz1719 —. 2021, MNRAS, 507, 116, doi: 10.1093/mnras/stab2048

    work page doi:10.1093/mnras/stz1719 2019

  26. [26]

    E., Chugunov, A

    Gusakov, M. E., Chugunov, A. I., & Kantor, E. M. 2014a, Phys. Rev. Lett., 112, 151101, doi: 10.1103/PhysRevLett.112.151101 —. 2014b, Phys. Rev. D, 90, 063001, doi: 10.1103/PhysRevD.90.063001

    work page doi:10.1103/physrevlett.112.151101

  27. [27]

    Horowitz, C. J. 2010, Phys. Rev. D, 81, 103001, doi: 10.1103/PhysRevD.81.103001

    work page doi:10.1103/physrevd.81.103001 2010

  28. [28]

    J., & Jones, D

    Hutchins, T. J., & Jones, D. I. 2023, MNRAS, 522, 226, doi: 10.1093/mnras/stad967

    work page doi:10.1093/mnras/stad967 2023

  29. [29]

    Jaranowski, P., Kr´ olak, A., & Schutz, B. F. 1998, Phys. Rev. D, 58, 063001, doi: 10.1103/PhysRevD.58.063001

    work page doi:10.1103/physrevd.58.063001 1998

  30. [30]

    I., & Riles, K

    Jones, D. I., & Riles, K. 2025, Class. Quant. Grav., 42, 033001, doi: 10.1088/1361-6382/ada244

    work page doi:10.1088/1361-6382/ada244 2025

  31. [31]

    2016, Phys

    Keitel, D. 2016, Phys. Rev. D, 93, 084024, doi: 10.1103/PhysRevD.93.084024

    work page doi:10.1103/physrevd.93.084024 2016

  32. [32]

    2015, Phys

    Leaci, P., & Prix, R. 2015, Phys. Rev. D, 91, 102003, doi: 10.1103/PhysRevD.91.102003

    work page doi:10.1103/physrevd.91.102003 2015

  33. [33]

    The ATNF Pulsar Catalogue

    Manchester, R. N., Hobbs, G. B., Teoh, A., & Hobbs, M. 2005, Astronom. J., 129, 1993–2006, doi: 10.1086/428488

    work page internal anchor Pith review doi:10.1086/428488 2005

  34. [34]

    2018, Phys

    Mukherjee, A., Messenger, C., & Riles, K. 2018, Phys. Rev. D, 97, 043016, doi: 10.1103/PhysRevD.97.043016

    work page doi:10.1103/physrevd.97.043016 2018

  35. [35]

    Owen, B. J. 2005, Phys. Rev. Lett., 95, 211101, doi: 10.1103/PhysRevLett.95.211101 —. 2010, Phys. Rev. D, 82, 104002, doi: 10.1103/PhysRevD.82.104002

    work page doi:10.1103/physrevlett.95.211101 2005

  36. [36]

    Patruno, A., & Watts, A. L. 2020, Accreting Millisecond X-ray Pulsars (Springer Berlin Heidelberg), 143–208, doi: 10.1007/978-3-662-62110-3 4

    work page doi:10.1007/978-3-662-62110-3 2020

  37. [37]

    2023, Liv

    Riles, K. 2023, Liv. Rev. in Relat., 26, 1, doi: 10.1007/s41114-023-00044-3

    work page doi:10.1007/s41114-023-00044-3 2023

  38. [38]

    Rossetto, P. H. B., Frauendiener, J., & Melatos, A. 2025, Astrophys. J., 979, 10, doi: 10.3847/1538-4357/ada276

    work page doi:10.3847/1538-4357/ada276 2025

  39. [39]

    2020, MNRAS, 493, 3866, doi: 10.1093/mnras/staa442

    Singh, N., Haskell, B., Mukherjee, D., & Bulik, T. 2020, MNRAS, 493, 3866, doi: 10.1093/mnras/staa442

    work page doi:10.1093/mnras/staa442 2020

  40. [40]

    2022, Phys

    Steltner, B., Papa, M., & Eggenstein, H. 2022, Phys. Rev. D, 105, 022005, doi: 10.1103/PhysRevD.105.022005

    work page doi:10.1103/physrevd.105.022005 2022

  41. [41]

    A., Eggenstein, H.-B., et al

    Steltner, B., Papa, M. A., Eggenstein, H.-B., et al. 2021, Astrophys. J., 909, 79, doi: 10.3847/1538-4357/abc7c9

    work page doi:10.3847/1538-4357/abc7c9 2021

  42. [42]

    Tenorio, R., Keitel, D., & Sintes, A. M. 2021, Universe, 7, 474, doi: 10.3390/universe7120474

    work page doi:10.3390/universe7120474 2021

  43. [43]

    2023, Astroparticle Physics, 153, 102880, doi: 10.1016/j.astropartphys.2023.102880

    Wette, K. 2023, Astroparticle Physics, 153, 102880, doi: 10.1016/j.astropartphys.2023.102880

    work page doi:10.1016/j.astropartphys.2023.102880 2023