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REVIEW 2 major objections 1 minor 84 references

Acoustic black holes produce larger Einstein rings, longer microlensing events, and higher peak magnifications than Schwarzschild black holes as the tuning parameter ξ grows.

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2026-06-25 20:36 UTC pith:S6H5SOO5

load-bearing objection The acoustic metric substitution into microlensing formulas has no physical basis. the 2 major comments →

arxiv 2606.25565 v1 pith:S6H5SOO5 submitted 2026-06-24 gr-qc

Galactic microlensing by acoustic Schwarzschild black holes

G. F. Akhtaryanova , R. Kh. Karimov , U. K. Khidirov , R. N. Izmailov This is my paper
classification gr-qc
keywords acoustic black holesgalactic microlensingSchwarzschild metrictuning parameter ξEinstein ring radiusPaczyński light curvesevent durationanalogue gravity
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

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

The paper calculates microlensing light curves for acoustic Schwarzschild black holes, which are characterized by a fluid-dynamical metric controlled by the tuning parameter ξ. It applies the metric to observed black hole candidates treated as galactic lenses and compares the results directly to the vacuum Schwarzschild case. Larger values of ξ increase the Einstein ring radius, extend event duration, raise peak magnification in the Paczyński curves, and raise the overall microlensing event rate. These changes imply that statistical patterns in microlensing survey data could distinguish acoustic metrics from standard vacuum solutions.

Core claim

Using the acoustic Schwarzschild metric with tuning parameter ξ, the deflection angle and resulting Paczyński light curves show that larger ξ values increase the Einstein ring radius, prolong the microlensing event duration, and elevate the peak magnification compared to the ξ=0 Schwarzschild case. Consequently, the microlensing event rate and detection probability rise with ξ when applied to galactic black hole candidates.

What carries the argument

The acoustic tuning parameter ξ that parametrizes deviations from the vacuum Schwarzschild metric and enters the deflection-angle calculation for microlensing observables.

Load-bearing premise

Acoustic black holes with the same mass and distance parameters as observed candidates can be treated as gravitational lenses whose metric is fully specified by ξ and produces observable differences from the vacuum Schwarzschild metric at galactic scales.

What would settle it

A direct comparison of microlensing event statistics and light-curve parameters from current surveys against model predictions for different fixed values of ξ; if the data are consistent only with ξ equal to zero within measurement uncertainties, the claim of observable enhancement would be ruled out.

Watch this falsifier — get emailed when new claim-graph text bears on it.

If this is right

  • The Einstein ring radius increases with rising ξ.
  • Microlensing event durations become longer as ξ grows.
  • Peak magnification in the light curves rises with ξ.
  • The microlensing event rate is higher for acoustic black holes than for their Schwarzschild counterparts.
  • The probability of detection grows as a function of ξ.

Where Pith is reading between the lines

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

  • Microlensing surveys could place limits on ξ by comparing aggregate statistics of events attributed to black hole candidates against the ξ=0 baseline.
  • If acoustic metrics are realized in nature, the same lensing modifications might appear in other analogue-gravity systems whose metrics admit a similar tuning parameter.
  • The approach supplies a concrete observational channel for testing whether dark-matter halo objects obey vacuum general relativity or fluid-based analogues at galactic distances.

Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

2 major / 1 minor

Summary. The manuscript explores galactic microlensing by acoustic Schwarzschild black holes parameterized by a tuning parameter ξ, treating them as potential dark matter halo objects. Using observed parameters from black hole candidates (Cygnus X-1, A0620-00, GRO J1655-40) as lenses, it calculates that increasing ξ produces a larger Einstein ring radius, longer event duration, higher peak magnification in Paczyński light curves, and an enhanced microlensing event rate relative to standard Schwarzschild black holes, proposing microlensing surveys as a channel to constrain analogue gravity metrics.

Significance. If the metric substitution were valid, the work would supply concrete, survey-accessible predictions that could test analogue models at galactic scales using existing microlensing data sets. The choice to anchor calculations to real observed BH parameters rather than purely theoretical ones is a strength, lending specificity to the claimed trends.

major comments (2)
  1. [Abstract] Abstract: the central claim that acoustic black holes produce ξ-dependent enhancements in Einstein radius, duration, peak magnification, and event rate rests on direct substitution of the acoustic line element into the standard Paczyński microlensing expressions, yet no derivation of the light-deflection angle from the null geodesic equation of the acoustic metric is supplied, nor is any argument given that this effective fluid metric governs photon propagation.
  2. [Abstract] Abstract: the reported directional trends with ξ are stated without equations, error budgets, data-exclusion criteria, or tests of robustness against changes in modeling assumptions (e.g., lens mass/distance priors or source distributions), so the soundness of the quantitative claims cannot be evaluated.
minor comments (1)
  1. [Abstract] Abstract: the Paczyński light-curve reference contains a typesetting artifact (Paczy\'{n}ski).

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive comments on our manuscript. We address each major comment point by point below, indicating revisions where appropriate.

read point-by-point responses

  1. Referee: [Abstract] Abstract: the central claim that acoustic black holes produce ξ-dependent enhancements in Einstein radius, duration, peak magnification, and event rate rests on direct substitution of the acoustic line element into the standard Paczyński microlensing expressions, yet no derivation of the light-deflection angle from the null geodesic equation of the acoustic metric is supplied, nor is any argument given that this effective fluid metric governs photon propagation.

    Authors: We agree that an explicit derivation of the deflection angle from the null geodesic equation in the acoustic metric, together with a justification for photon propagation under the effective fluid metric, would strengthen the presentation. The current manuscript proceeds by direct substitution into the standard Paczyński formalism, which is common in analogue-gravity literature but lacks the requested derivation. We will add a new subsection deriving the deflection angle and discussing the applicability of the acoustic metric to null geodesics. revision: yes

  2. Referee: [Abstract] Abstract: the reported directional trends with ξ are stated without equations, error budgets, data-exclusion criteria, or tests of robustness against changes in modeling assumptions (e.g., lens mass/distance priors or source distributions), so the soundness of the quantitative claims cannot be evaluated.

    Authors: The directional trends with ξ are computed from the explicit expressions and numerical evaluations given in Sections 3 and 4, using the observed parameters of Cygnus X-1, A0620-00 and GRO J1655-40. We acknowledge, however, that the manuscript does not presently include error budgets, data-exclusion criteria or systematic robustness tests against variations in lens-mass/distance priors or source distributions. We will expand the results section to incorporate these elements. revision: yes

Circularity Check

0 steps flagged

No circularity; forward computation from acoustic metric to microlensing observables

full rationale

The paper introduces the acoustic Schwarzschild metric parameterized by the tuning parameter ξ and performs a direct forward calculation of microlensing observables (Einstein ring radius, event duration, peak magnification, event rate) by substituting the metric into standard Paczyński light-curve formulas applied to observed stellar-mass black hole parameters. No step in the provided abstract or described chain reduces by construction to a fitted input relabeled as prediction, a self-definitional loop, or a load-bearing self-citation; the reported ξ-dependent enhancements are explicit consequences of varying the input parameter in the metric. The derivation remains self-contained as a comparative computation.

Axiom & Free-Parameter Ledger

1 free parameters · 2 axioms · 1 invented entities

The central claim rests on the acoustic metric being a valid description for macroscopic lenses, the identification of acoustic black holes with observed black-hole-candidate masses, and the standard thin-lens approximation for microlensing. ξ is the sole explicit free parameter.

free parameters (1)
  • ξ
    Tuning parameter of the acoustic metric that directly scales the reported changes in ring radius, duration, magnification, and event rate.
axioms (2)
  • domain assumption Acoustic black holes share an event horizon with Schwarzschild solutions but obey a fluid-dynamical description that permits a distinct metric parameterized by ξ.
    Invoked in the abstract to justify treating acoustic objects as novel lenses.
  • domain assumption The thin-lens and Paczyński light-curve formalism remains valid when the lens metric is replaced by the acoustic version.
    Implicit in the calculation of Einstein ring radius and light curves.
invented entities (1)
  • acoustic black holes as dark matter halo objects no independent evidence
    purpose: To serve as a novel class of microlenses whose signatures differ from vacuum black holes.
    Postulated in the abstract without independent evidence supplied.

pith-pipeline@v0.9.1-grok · 5769 in / 1571 out tokens · 35548 ms · 2026-06-25T20:36:21.001702+00:00 · methodology

0 comments
read the original abstract

This work explores the application of acoustic black holes as a novel class of lenses in Galactic microlensing, potentially representing dark matter halo objects. While sharing key features like an event horizon, their underlying fluid-dynamical description differs from the vacuum solutions of Einstein's equations, suggesting potentially distinct observational signatures. This work investigates these distinctions by calculating the galactic microlensing predictions for acoustic black holes and comparing them to the standard Schwarzschild case. Using the observed parameters of known black hole candidates (Cygnus X-1, A0620-00, GRO J1655-40) as illustrative lenses, we demonstrate that the acoustic black holes tuning parameter $\xi $ significantly alters key observables. Our results show that an increase in $\xi $ leads to a larger Einstein ring radius, a longer event duration, and a higher peak magnification in the microlensing Paczy\'{n}ski light curves. Furthermore, we find that the microlensing event rate is enhanced for acoustic black holes compared to their Schwarzschild counterparts, with the probability of detection growing with $\xi$. These findings establish galactic microlensing as a promising astrophysical channel for constraining analogue gravity metrics, with the primary effects being potentially detectable in the statistical analysis of current and future microlensing survey data.

Figures

Figures reproduced from arXiv: 2606.25565 by G. F. Akhtaryanova, R. Kh. Karimov, R. N. Izmailov, U. K. Khidirov.

Figure 1
Figure 1. Figure 1: FIG. 1: Lens geometry, where [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2: Acoustic black hole light curves for [PITH_FULL_IMAGE:figures/full_fig_p007_2.png] view at source ↗

discussion (0)

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Reference graph

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