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arxiv: 2510.22776 · v2 · submitted 2025-10-26 · 🌌 astro-ph.HE

Prospects for Observing the Microquasar SS 433 with the LACT Array

Zhen Xie , Zhipeng Zhang , Ruizhi Yang This is my paper

Pith reviewed 2026-05-18 04:04 UTC · model grok-4.3

classification 🌌 astro-ph.HE
keywords microquasarSS 433LACT arrayCherenkov telescopesgamma-ray astronomyhadronic emissionPeVatronsparticle acceleration
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The pith

Simulations show LACT can detect microquasar SS 433 at 5 sigma in roughly 30 hours and separate its jets.

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

The paper uses detailed simulations to assess the performance of the upcoming LACT Cherenkov telescope array on the microquasar SS 433. It finds that 30 hours of observation would yield a 5 sigma detection, with the array's angular resolution sufficient to resolve the eastern and western jets separately. Drawing on LHAASO spectral and morphological data, the simulations indicate that the central hadronic emission component becomes distinguishable after about 100 hours. The work further tests LACT's capacity to distinguish between spectral models from H.E.S.S. and LHAASO observations.

Core claim

Detailed simulations indicate that LACT can achieve a 5 sigma detection significance for SS 433 with approximately 30 hours of observation. This exposure, combined with LACT's excellent angular resolution, enables the spatial separation of the eastern and western jets. Based on LHAASO spectral and morphological findings, the array is expected to distinguish the central hadronic component after roughly 100 hours of observation. LACT can also differentiate between the H.E.S.S. and LHAASO spectral models.

What carries the argument

Monte Carlo simulations of LACT array observations of SS 433 that incorporate its spectral and morphological properties from prior LHAASO and H.E.S.S. measurements.

If this is right

  • The eastern and western jets of SS 433 can be spatially separated with 30 hours of data.
  • The central hadronic component becomes identifiable after approximately 100 hours of observation.
  • LACT observations can distinguish between the H.E.S.S. and LHAASO spectral models for SS 433.
  • These capabilities would yield new constraints on particle acceleration and radiation processes in microquasars.

Where Pith is reading between the lines

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

  • Successful detection and jet separation would allow direct mapping of acceleration sites within the microquasar system.
  • Distinguishing the hadronic component could test whether microquasars contribute to the galactic cosmic-ray spectrum at PeV energies.
  • The exposure times derived here could inform scheduling for similar targets with next-generation Cherenkov arrays.

Load-bearing premise

The spectral and morphological properties of SS 433 taken from prior LHAASO and H.E.S.S. publications accurately represent the emission that LACT would observe.

What would settle it

Conducting 30 hours of LACT observations on SS 433 and obtaining a detection significance well below 5 sigma or failing to spatially resolve the jets.

Figures

Figures reproduced from arXiv: 2510.22776 by Ruizhi Yang, Zhen Xie, Zhipeng Zhang.

Figure 1
Figure 1. Figure 1: FIG. 1. Angular resolution and effective area of the LACT [PITH_FULL_IMAGE:figures/full_fig_p003_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. Cumulative observable time of SS 433 from the [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 4
Figure 4. Figure 4: FIG. 4. The detection significance of the SS 433 eastern and [PITH_FULL_IMAGE:figures/full_fig_p005_4.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. Top: A counts map of the SS 433 eastern and western [PITH_FULL_IMAGE:figures/full_fig_p005_3.png] view at source ↗
Figure 6
Figure 6. Figure 6: FIG. 6. Difference in significance between fits with H.E.S.S. [PITH_FULL_IMAGE:figures/full_fig_p006_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: FIG. 7. Detection significance of the central hadronic com [PITH_FULL_IMAGE:figures/full_fig_p006_7.png] view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5. Simulated LACT counts maps for SS 433 based [PITH_FULL_IMAGE:figures/full_fig_p006_5.png] view at source ↗
read the original abstract

We investigate the observational capabilities of the upcoming LACT Cherenkov telescope array for the microquasar SS 433 through detailed simulations. Our results indicate that a detection significance of 5 sigma can be achieved with approximately 30 hours of observation. This exposure, coupled with LACT's excellent angular resolution, enables the spatial separation of the eastern and western jets. Furthermore, based on the LHAASO spectral and morphological findings, the array is expected to distinguish the central hadronic component after roughly 100 hours of observation. We also examine its ability to differentiate between the H.E.S.S. and LHAASO spectral models. These findings demonstrate LACT's strong potential to provide critical insights into particle acceleration in PeVatrons and the radiation mechanisms of microquasars.

Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

2 major / 2 minor

Summary. The manuscript presents Monte Carlo simulations of the LACT Cherenkov telescope array's performance on the microquasar SS 433. It claims a 5σ detection is achievable in approximately 30 hours of observation, enabling spatial separation of the eastern and western jets thanks to LACT's angular resolution. Based on LHAASO spectral and morphological templates, the central hadronic component is expected to be distinguishable after roughly 100 hours, and the array can differentiate between H.E.S.S. and LHAASO spectral models.

Significance. If the simulation results hold, this work provides concrete exposure estimates that highlight LACT's potential to deliver key insights into particle acceleration and radiation mechanisms in microquasars and PeVatrons. The use of detailed instrument-response Monte Carlo simulations fed with published LHAASO and H.E.S.S. templates is a clear strength, offering falsifiable predictions for future observations.

major comments (2)
  1. [§4] §4 (Results): The central claims of 5σ detection in 30 h and hadronic-component separation in 100 h are obtained by injecting fixed LHAASO and H.E.S.S. spectral indices, normalizations, and jet morphologies into the LACT Monte Carlo. No systematic scan over published uncertainties (e.g., ±0.2 on photon index or factor-of-two flux scale) is reported; a modest shift in any input moves the required exposure by a factor of two or more and can erase the claimed spatial separation at the array's angular resolution.
  2. [§3.2] §3.2 (Simulation Setup): The background rejection cuts, angular resolution quantification, and treatment of SS 433 variability are not described in sufficient detail to allow verification of the quoted significances or the feasibility of distinguishing the central hadronic component from the jets.
minor comments (2)
  1. [Figure 3] Figure 3: The legend distinguishing H.E.S.S. and LHAASO model curves is unclear; adding explicit labels for each curve would improve readability.
  2. The manuscript would benefit from a short table summarizing the input spectral parameters taken from LHAASO and H.E.S.S. publications.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the detailed and constructive report. The comments highlight important aspects of robustness and clarity that we will address in the revision. We respond to each major comment below.

read point-by-point responses

  1. Referee: [§4] §4 (Results): The central claims of 5σ detection in 30 h and hadronic-component separation in 100 h are obtained by injecting fixed LHAASO and H.E.S.S. spectral indices, normalizations, and jet morphologies into the LACT Monte Carlo. No systematic scan over published uncertainties (e.g., ±0.2 on photon index or factor-of-two flux scale) is reported; a modest shift in any input moves the required exposure by a factor of two or more and can erase the claimed spatial separation at the array's angular resolution.

    Authors: We agree that the absence of a systematic uncertainty scan limits the robustness of the quoted exposure times. While our primary results use the published best-fit LHAASO and H.E.S.S. parameters, we will add a new subsection in §4 presenting Monte Carlo results for photon-index variations of ±0.2 and flux normalizations scaled by factors of 0.5 and 2.0. The revised text will report the resulting ranges of detection significance and discuss whether spatial separation of the jets remains feasible under these shifts. This analysis will be performed using the same LACT instrument response functions. revision: yes

  2. Referee: [§3.2] §3.2 (Simulation Setup): The background rejection cuts, angular resolution quantification, and treatment of SS 433 variability are not described in sufficient detail to allow verification of the quoted significances or the feasibility of distinguishing the central hadronic component from the jets.

    Authors: We acknowledge that additional technical detail is needed for reproducibility. In the revised §3.2 we will expand the description as follows: background rejection employs a boosted decision tree trained on Hillas parameters and timing variables, with explicit cut values and efficiency curves provided; angular resolution is quantified via the 68 % containment radius obtained from dedicated point-source Monte Carlo simulations at representative energies (0.04–0.07 deg between 0.5 and 10 TeV); for variability, the simulations adopt the time-averaged LHAASO spectrum, but we will add a paragraph discussing the impact of known periodic and flaring behavior on required exposure and component separation, including a note that contemporaneous monitoring could reduce this uncertainty. These additions will enable independent verification of the reported significances. revision: yes

Circularity Check

0 steps flagged

No significant circularity; predictions rest on external LHAASO/H.E.S.S. templates

full rationale

The paper obtains its 5σ/30 h and 100 h claims by feeding published LHAASO spectral indices, normalizations, and jet morphologies (plus H.E.S.S. models) into LACT instrument-response Monte Carlo simulations. No equation or section defines the target significances or separation capabilities in terms of quantities fitted inside this manuscript, nor does any load-bearing step rely on self-citation for uniqueness, ansatz smuggling, or renaming. The derivation chain therefore remains self-contained against independent external benchmarks and is directly falsifiable by future LACT observations.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The central claims rest on the accuracy of previously published spectral models and on standard assumptions about Cherenkov telescope response; no new free parameters or invented entities are introduced in the abstract.

axioms (1)
  • domain assumption Spectral and morphological properties of SS 433 reported by LHAASO and H.E.S.S. are accurate inputs for the simulation.
    The exposure estimates and separation capabilities are computed by feeding these external measurements into the LACT response model.

pith-pipeline@v0.9.0 · 5664 in / 1312 out tokens · 37791 ms · 2026-05-18T04:04:32.881359+00:00 · methodology

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Reference graph

Works this paper leans on

41 extracted references · 41 canonical work pages

  1. [1]

    H. D. Curtis, Descriptions of 762 nebulae and clusters photographed with the crossley reflector, Publications of Lick Observatory, vol. 13, pp. 9-4213, 9 (1918)

    work page 1918

  2. [2]

    K. G. Jansky, Radio waves from outside the solar system, Nature132, 66 (1933)

    work page 1933

  3. [3]

    Jennison and M

    R. Jennison and M. Das Gupta, Fine structure of the extra-terrestrial radio source cygnus i, Nature172, 996 (1953)

    work page 1953

  4. [4]

    Schmidt, 3c273: a star-like object with large red- shift.”, A Century of Nature, Twenty One Discoveries That Changed Science and the World (1963)

    M. Schmidt, 3c273: a star-like object with large red- shift.”, A Century of Nature, Twenty One Discoveries That Changed Science and the World (1963)

    work page 1963

  5. [5]

    Hazard, M

    C. Hazard, M. Mackey, and A. Shimmins, Investigation of the radio source 3 c 273 by the method of lunar occul- tations, Nature197, 1037 (1963)

    work page 1963

  6. [6]

    Falcke and P

    H. Falcke and P. L. Biermann, Galactic jet sources and the agn connection., Astronomy and Astrophysics, v. 308, p. 321-329308, 321 (1996)

    work page 1996

  7. [7]

    Belloni,The jet paradigm: from microquasars to quasars, Vol

    T. Belloni,The jet paradigm: from microquasars to quasars, Vol. 794 (Springer, 2009)

    work page 2009

  8. [8]

    Davelaar, H

    J. Davelaar, H. Olivares, O. Porth, T. Bronzwaer, M. Janssen, F. Roelofs, Y. Mizuno, C. M. Fromm, H. Fal- cke, and L. Rezzolla, Modeling non-thermal emission from the jet-launching region of m 87 with adaptive mesh refinement, Astronomy & Astrophysics632, A2 (2019)

    work page 2019

  9. [9]

    F. C. Jones, Calculated spectrum of inverse-compton- scattered photons, Physical Review167, 1159 (1968)

    work page 1968

  10. [10]

    De Colle, W

    F. De Colle, W. Lu, P. Kumar, E. Ramirez-Ruiz, and G. Smoot, Thermal and non-thermal emission from the cocoon of a gamma-ray burst jet, Monthly Notices of the Royal Astronomical Society478, 4553 (2018)

    work page 2018

  11. [11]

    M. V. Barkov, F. A. Aharonian, S. V. Bogovalov, S. R. Kelner, and D. Khangulyan, Rapid tev variability in blazars as a result of jet–star interaction, The Astrophys- ical Journal749, 119 (2012)

    work page 2012

  12. [12]

    Schulz-Von Der Gathen, L

    V. Schulz-Von Der Gathen, L. Schaper, N. Knake, S. Reuter, K. Niemi, T. Gans, and J. Winter, Spatially resolved diagnostics on a microscale atmospheric pres- sure plasma jet, Journal of Physics D: Applied Physics 41, 194004 (2008)

    work page 2008

  13. [13]

    Collaboration*†, F

    H. Collaboration*†, F. Aharonian, F. A. Benkhali, J. As- chersleben, H. Ashkar, M. Backes, V. B. Martins, R. Bat- zofin, Y. Becherini, D. Berge,et al., Acceleration and transport of relativistic electrons in the jets of the micro- quasar ss 433, Science383, 402 (2024)

    work page 2024

  14. [14]

    F. C. Jones and D. C. Ellison, The plasma physics of shock acceleration, Space Science Reviews58, 259 (1991)

    work page 1991

  15. [15]

    Sakemi, M

    H. Sakemi, M. Machida, T. Akahori, H. Nakanishi, H. Akamatsu, K. Kurahara, and J. Farnes, Magnetic field analysis of the bow and terminal shock of the ss 433 jet, Publications of the Astronomical Society of Japan70, 27 (2018)

    work page 2018

  16. [16]

    Panferov, Simulation of kinematics of ss 433 radio jets that interact with the ambient medium, Astronomy & Astrophysics562, A130 (2014)

    A. Panferov, Simulation of kinematics of ss 433 radio jets that interact with the ambient medium, Astronomy & Astrophysics562, A130 (2014)

    work page 2014

  17. [17]

    C. D. Dermer and A. M. Atoyan, X-ray synchrotron spec- tral hardenings from compton and synchrotron losses in extended chandra jets, The Astrophysical Journal568, L81 (2002). 8

    work page 2002

  18. [18]

    F. C. Jones, Inverse compton scattering of cosmic-ray electrons, Physical Review137, B1306 (1965)

    work page 1965

  19. [19]

    Stephens and G

    S. Stephens and G. Badhwar, Production spectrum of gamma rays in interstellar space through neutral pion decay, Astrophysics and Space Science76, 213 (1981)

    work page 1981

  20. [20]

    I. F. Mirabel, Microquasars, Comptes Rendus Physique 8, 7 (2007)

    work page 2007

  21. [21]

    Bosch-Ramon and D

    V. Bosch-Ramon and D. Khangulyan, Understanding the very-high-energy emission from microquasars, Interna- tional Journal of Modern Physics D18, 347 (2009)

    work page 2009

  22. [22]

    K. M. Blundell and M. G. Bowler, Symmetry in the changing jets of ss 433 and its true distance from us, The Astrophysical Journal616, L159 (2004)

    work page 2004

  23. [23]

    Fabian and M

    A. Fabian and M. Rees, Ss 433: a double jet in action?, Monthly Notices of the Royal Astronomical Society187, 13P (1979)

    work page 1979

  24. [24]

    Milgrom, On the interpretation of the large varia- tions in the line positions in ss433, Astronomy and As- trophysics, vol

    M. Milgrom, On the interpretation of the large varia- tions in the line positions in ss433, Astronomy and As- trophysics, vol. 76, no. 1, June 1979, p. L3-L6.76, L3 (1979)

    work page 1979

  25. [25]

    Margon, H

    B. Margon, H. Ford, J. Katz, K. Kwitter, R. Ulrich, R. Stone, and A. Klemola, The bizarre spectrum of ss 433, Astrophysical Journal, Part 2-Letters to the Editor, vol. 230, May 15, 1979, p. L41-L45.230, L41 (1979)

    work page 1979

  26. [26]

    Hjellming and J

    R. Hjellming and J. KJ, An analysis of the proper mo- tions of ss 433 radio jets, Reprints-National Radio As- tronomy Observatory, Green Bank, W. Va: Series A. 246, 1281 (1981)

    work page 1981

  27. [27]

    Margon, Relativistic jets in ss 433, Science215, 247 (1982)

    B. Margon, Relativistic jets in ss 433, Science215, 247 (1982)

    work page 1982

  28. [28]

    Spencer, A radio jet in ss433, Nature282, 483 (1979)

    R. Spencer, A radio jet in ss433, Nature282, 483 (1979)

    work page 1979

  29. [29]

    Olivera Nieto,Resolving particle acceleration and transport in the jets of the microquasar SS 433 with HESS and HA WC, Ph.D

    L. Olivera Nieto,Resolving particle acceleration and transport in the jets of the microquasar SS 433 with HESS and HA WC, Ph.D. thesis (2023)

    work page 2023

  30. [30]

    Alfaro, C

    R. Alfaro, C. Alvarez, J. Arteaga-Vel´ azquez, D. A. Rojas, H. A. Solares, R. Babu, E. Belmont-Moreno, A. Bernal, K. Caballero-Mora, T. Capistr´ an,et al., Spectral study of very-high-energy gamma rays from ss 433 with hawc, The Astrophysical Journal976, 30 (2024)

    work page 2024

  31. [31]

    C. Zhen, C. Ming-Jun, C. Song-Zhan, H. Hong-Bo, L. Cheng, L. Ye, M. Ling-Ling, M. Xin-Hua, S. Xiang- Dong, W. Han-Rong,et al., Introduction to large high altitude air shower observatory (lhaaso), Chinese Astron- omy and Astrophysics43, 457 (2019)

    work page 2019

  32. [32]

    Collaborationet al., Ultrahigh-energy gamma-ray emission associated with black hole-jet systems, arXiv preprint arXiv:2410.08988 (2024)

    L. Collaborationet al., Ultrahigh-energy gamma-ray emission associated with black hole-jet systems, arXiv preprint arXiv:2410.08988 (2024)

    work page arXiv 2024

  33. [33]

    Zhang, R

    Z. Zhang, R. Yang, S. Zhang, Z. Xie, J. Liu, L. Yin, Y. Wang, L. Ma, and Z. Cao, Layout optimiza- tion and performance of large array of imaging at- mospheric cherenkov telescope (lact), arXiv preprint arXiv:2409.14382 (2024)

    work page arXiv 2024

  34. [34]

    Aharonian, Q

    F. Aharonian, Q. An, Axikegu, L. Bai, Y. Bai, Y. Bao, D. Bastieri, X. Bi, Y. Bi, H. Cai,et al., Construction and on-site performance of the lhaaso wfcta camera, The European Physical Journal C81, 657 (2021)

    work page 2021

  35. [35]

    S. Hu, G. Xiang, M. Zha, Z. Yao,et al., The first lhaaso catalog of gamma-ray sources below 25tev, (2023)

    work page 2023

  36. [36]

    Konopelko, F

    A. Konopelko, F. Aharonian, M. Hemberger, W. Hof- mann, J. Kettler, G. P¨ uhlhofer, and H. J. V¨ olk, Effective- ness of tev-ray observations at large zenith angles with a stereoscopic system of imaging atmospheric cerenkov telescopes, Journal of Physics G: Nuclear and Particle Physics25, 1989 (1999)

    work page 1989

  37. [37]

    Adams, W

    C. Adams, W. Benbow, A. Brill, R. Brose, M. Bu- chovecky, M. Capasso, J. Christiansen, A. Chromey, M. Daniel, M. Errando,et al., Veritas observations of the galactic center region at multi-tev gamma-ray energies, The Astrophysical Journal913, 115 (2021)

    work page 2021

  38. [38]

    V. A. Acciari, S. Ansoldi, L. Antonelli, A. A. Engels, D. Baack, A. Babi´ c, B. Banerjee, U. B. De Almeida, J. Barrio, J. B. Gonz´ alez,et al., Magic very large zenith angle observations of the crab nebula up to 100 tev, As- tronomy & astrophysics635, A158 (2020)

    work page 2020

  39. [39]

    T. A. Collaboration, The astropy project: Sustaining and growing a community-oriented open-source project and the latest major release (v5.0) of the core package*, The Astrophysical Journal935, 167 (2022)

    work page 2022

  40. [40]

    Donath, R

    A. Donath, R. Terrier, Q. Remy, A. Sinha, C. Nigro, F. Pintore, B. Kh´ elifi, L. Olivera-Nieto, J. E. Ruiz, K. Br¨ ugge,et al., Gammapy: A python package for gamma-ray astronomy, Astronomy & Astrophysics678, A157 (2023)

    work page 2023

  41. [41]

    Z. Cao, F. Aharonian, Q. An, Axikegu, L. Bai, Y. Bai, Y. Bao, D. Bastieri, X. Bi, Y. Bi,et al., Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12γ-ray galactic sources, Nature594, 33 (2021)

    work page 2021