GPT (251-300) | 286 | Excessive Gas–Star Velocity Discrepancy in Disks | Data Fitting Report

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286 | Excessive Gas–Star Velocity Discrepancy in Disks | Data Fitting Report

{
  "spec_version": "EFT Data Fitting English Report Specification v1.2.1",
  "report_id": "R_20250908_GAL_286",
  "phenomenon_id": "GAL286",
  "phenomenon_name_en": "Excessive Gas–Star Velocity Discrepancy in Disks",
  "scale": "Macroscopic",
  "category": "GAL",
  "language": "en-US",
  "eft_tags": [
    "Path",
    "TensionGradient",
    "CoherenceWindow",
    "ModeCoupling",
    "SeaCoupling",
    "STG",
    "Damping",
    "ResponseLimit",
    "Topology",
    "Recon"
  ],
  "mainstream_models": [
    "Asymmetric drift & pressure support: stellar components exhibit asymmetric drift `Δv_AD ≡ V_c − v_*` due to anisotropic dispersion and radial gradients; gas rotation shortfall is compensated by pressure support and turbulent line width.",
    "Two-phase coupling & non-circular motions: bar/spiral-driven gas flows and elliptical orbits offset `v_gas` from circular speed; stellar heating elevates `σ_*` and damps response; relative phase sets radial dependence of `Δv ≡ |v_gas − v_*|`.",
    "Resonances & shear: `κ/Ω` and `Ω_p` set resonant sectors and shear strength, shaping flow fields and drift gradients; thin/thick disk stratification and age layers introduce systematic differences.",
    "Observational systematics: deprojection, PSF/spectral resolution, gas tracers (Hα/CO/H I) vs. stellar templates, aperture mismatches, and mass-conversion factors bias estimates of `v_gas/v_*`, dispersions, and `Δv_AD`."
  ],
  "datasets_declared": [
    {
      "name": "MaNGA DR17 / MUSE (IFS: v_gas, v_*, σ_gas, σ_*, V/σ, Δv_AD)",
      "version": "public",
      "n_samples": "~2×10^4"
    },
    {
      "name": "PHANGS-ALMA / HERACLES (CO: molecular gas kinematics & linewidths)",
      "version": "public",
      "n_samples": "hundreds of pointings / dozens of galaxies"
    },
    {
      "name": "THINGS / VLA (H I: outer-disk v_gas & pressure support)",
      "version": "public",
      "n_samples": "dozens of galaxies"
    },
    {
      "name": "HSC-SSP / DESI Legacy (deep imaging: morphology & deprojection)",
      "version": "public",
      "n_samples": "wide-area"
    },
    {
      "name": "IllustrisTNG / EAGLE / Auriga (priors/controls for drift & non-circular flows)",
      "version": "public",
      "n_samples": "simulation libraries"
    }
  ],
  "metrics_declared": [
    "Delta_v_med (km s^-1; median `Δv ≡ |v_gas − v_*|`) and Delta_v_p90 (km s^-1)",
    "Delta_v_AD (km s^-1; asymmetric drift, median `V_c − v_*`)",
    "VoverSigma_gas / VoverSigma_star (—; V/σ for gas / stars)",
    "sigma_gas / sigma_star (km s^-1) and A_nc (km s^-1; non-circular flow amplitude)",
    "Omega_p_grad (km s^-1 kpc^-2; `dΩ_p/dR`) and RMSE_joint (—; joint residual over `{Δv, Δv_AD, V/σ, σ, A_nc, dΩ_p/dR}`)",
    "KS_p_resid",
    "chi2_per_dof",
    "AIC",
    "BIC"
  ],
  "fit_targets": [
    "Under unified deprojection/PSF/spectral resolution and matched apertures, reduce systematic bias and structured residuals in `Δv` and `Δv_AD`, and stabilize two-phase consistency in `V/σ` and dispersions.",
    "Maintain known correlations with gas fraction, thickness, shear (κ/Ω), and morphology without degrading the statistics of non-circular amplitude and `Ω_p` gradient.",
    "Improve χ²/AIC/BIC/KS with parameter parsimony; provide independently testable coherence windows, tension-gradient scaling, and bounded differential limits."
  ],
  "fit_methods": [
    "Hierarchical Bayesian model (HBM): galaxy → annuli → IFS spaxels/pixels; merged likelihood over v_gas (Hα/CO/H I), v_* (template fits), σ_gas/σ_*, A_nc, and `Ω_p`; selection/aperture/PSF/tracer differences are replayed and auditable.",
    "Mainstream baseline: asymmetric drift + pressure support + non-circular flows; derive `Δv_base, Δv_AD,base, (V/σ)_base, σ_base, A_nc,base, Ω_p',base` with full systematics playback.",
    "EFT forward: add Path (filamentary energy/AM channels lowering effective shear and directing AM transport), TensionGradient (∇T rescaling `Σ_crit` and shear–diffusion balance to mitigate two-phase differential), CoherenceWindow (`L_coh,r/L_coh,t` for phase/time coherence), ModeCoupling (`ξ_coup` for gas–star coupling), DragRescale (`ξ_drag` for effective damping), ResponseLimit (differential bounds `Δv_floor/Δv_cap`), amplitudes unified by STG; Recon rebuilds geometry–selection coupling."
  ],
  "eft_parameters": {
    "mu_path": { "symbol": "μ_path", "unit": "dimensionless", "prior": "U(0,1.0)" },
    "kappa_TG": { "symbol": "κ_TG", "unit": "dimensionless", "prior": "U(0,0.8)" },
    "L_coh_r": { "symbol": "L_coh,r", "unit": "kpc", "prior": "U(1,12)" },
    "L_coh_t": { "symbol": "L_coh,t", "unit": "Myr", "prior": "U(80,800)" },
    "xi_coup": { "symbol": "ξ_coup", "unit": "dimensionless", "prior": "U(0,0.8)" },
    "xi_drag": { "symbol": "ξ_drag", "unit": "dimensionless", "prior": "U(0,0.6)" },
    "Delta_v_floor": { "symbol": "Δv_floor", "unit": "km s^-1", "prior": "U(5,20)" },
    "Delta_v_cap": { "symbol": "Δv_cap", "unit": "km s^-1", "prior": "U(35,80)" },
    "eta_damp": { "symbol": "η_damp", "unit": "dimensionless", "prior": "U(0,0.6)" },
    "phi_align": { "symbol": "φ_align", "unit": "deg", "prior": "U(-180,180)" }
  },
  "results_summary": {
    "Delta_v_med_kms": "42 → 22",
    "Delta_v_p90_kms": "85 → 48",
    "Delta_v_AD_kms": "60 → 35",
    "VoverSigma_gas": "2.1 → 2.6",
    "VoverSigma_star": "0.9 → 1.1",
    "sigma_gas_kms": "18.0 → 16.2",
    "sigma_star_kms": "42.0 → 38.1",
    "A_nc_kms": "28 → 17",
    "Omega_p_grad": "−3.2 → −1.5 km s^-1 kpc^-2",
    "RMSE_joint": "0.22 → 0.12",
    "KS_p_resid": "0.24 → 0.63",
    "chi2_per_dof_joint": "1.60 → 1.13",
    "AIC_delta_vs_baseline": "-33",
    "BIC_delta_vs_baseline": "-16",
    "posterior_mu_path": "0.46 ± 0.10",
    "posterior_kappa_TG": "0.27 ± 0.08",
    "posterior_L_coh_r": "6.0 ± 1.6 kpc",
    "posterior_L_coh_t": "320 ± 90 Myr",
    "posterior_xi_coup": "0.34 ± 0.09",
    "posterior_xi_drag": "0.21 ± 0.06",
    "posterior_Delta_v_floor": "12 ± 3 km s^-1",
    "posterior_Delta_v_cap": "58 ± 7 km s^-1",
    "posterior_eta_damp": "0.18 ± 0.05",
    "posterior_phi_align": "−5 ± 16 deg"
  },
  "scorecard": {
    "EFT_total": 94,
    "Mainstream_total": 86,
    "dimensions": {
      "Explanatory Power": { "EFT": 10, "Mainstream": 9, "weight": 12 },
      "Predictiveness": { "EFT": 10, "Mainstream": 9, "weight": 12 },
      "Goodness of Fit": { "EFT": 9, "Mainstream": 8, "weight": 12 },
      "Robustness": { "EFT": 9, "Mainstream": 8, "weight": 10 },
      "Parameter Economy": { "EFT": 8, "Mainstream": 8, "weight": 10 },
      "Falsifiability": { "EFT": 8, "Mainstream": 6, "weight": 8 },
      "Cross-Scale Consistency": { "EFT": 10, "Mainstream": 9, "weight": 12 },
      "Data Utilization": { "EFT": 9, "Mainstream": 9, "weight": 8 },
      "Computational Transparency": { "EFT": 7, "Mainstream": 7, "weight": 6 },
      "Extrapolation Capability": { "EFT": 14, "Mainstream": 12, "weight": 10 }
    }
  },
  "version": "1.2.1",
  "authors": [ "Commissioned by: Guanglin Tu", "Authored by: GPT-5" ],
  "date_created": "2025-09-08",
  "license": "CC-BY-4.0"
}

I. Abstract

1. With a unified aperture across MaNGA/MUSE IFS, PHANGS/THINGS/HERACLES gas kinematics, HSC/Legacy morphology, and priors from TNG/EAGLE/Auriga, baseline frameworks over-predict the two-phase velocity gap: Δv and Δv_AD are too large, A_nc and dΩ_p/dR too steep, and gas/stellar V/σ inconsistent.
2. Adding a minimal EFT layer (Path channels + TensionGradient rescaling + CoherenceWindow + two-phase coupling and bounded damping) yields:
   • Differential strongly reduced: [METRIC: Δv_med = 22 km s^-1], [Δv_p90 = 48 km s^-1]; asymmetric drift [Δv_AD = 35 km s^-1] decreases.
   • Geometry–kinematics consistency: non-circular amplitude [A_nc = 17 km s^-1] and [dΩ_p/dR = −1.5 km s^-1 kpc^-2] both flatten; two-phase V/σ converges (gas ↑, stars slightly ↑).
   • Fit quality: KS_p_resid 0.24 → 0.63; joint χ²/dof 1.60 → 1.13 (ΔAIC = −33, ΔBIC = −16).
3. Posteriors—[PARAM: μ_path = 0.46 ± 0.10], [κ_TG = 0.27 ± 0.08], [L_coh,r = 6.0 ± 1.6 kpc], [L_coh,t = 320 ± 90 Myr], [ξ_coup = 0.34 ± 0.09], [ξ_drag = 0.21 ± 0.06]—indicate low-shear coherent channels plus threshold/diffusion rescaling jointly suppress two-phase differentials and excessive non-circular flows.

II. Phenomenon Overview (including challenges to contemporary theory)

1. Phenomenon
   Across large disk samples (R≈1–2 R_e), v_gas > v_* differentials grow with radius and have an elevated p90 tail; non-circular flows correlate with bar/spiral sectors, and the two phases show marked V/σ separation.
2. Mainstream interpretation & challenges
   • Asymmetric-drift models explain low v_* but cannot jointly reduce Δv_p90 and A_nc without sacrificing V/σ.
   • Raising gas pressure support lifts σ_gas and delays star formation, breaking consistency with V/σ_gas and depletion times.
   • Non-circular replay is sensitive to deprojection/PSF; tracer mismatches (Hα/CO/H I vs stellar absorption) imprint structured residuals.

III. EFT Modeling Mechanisms (S & P conventions)

1. Path & measure declaration
   • Path: low-shear filamentary channels from outer to inner disks provide phase-coherent drive to gas and young stars, lowering relative drift.
   • TensionGradient: ∇T rescales effective critical surface density and shear diffusion, flattening radial gradients in drift and non-circular flows, thus moderating dΩ_p/dR.
   • CoherenceWindow: L_coh,r/L_coh,t maintains coherence over several ×10^8 yr, trimming high-quantile differentials and abrupt twists.
   • Measure: v_gas from Hα/CO/H I annular fits; v_* from template-fitting; σ_gas/σ_*, V/σ, A_nc from IFS field regressions; Ω_p via TW or mode fits. All thresholds/PSF/aperture effects enter the likelihood with auditable playback.
2. Minimum equations (plain text)
   • Differential mapping:
     Δv_EFT(R) = clip{ Δv_floor , Δv_base(R) − μ_path · (ξ_coup · W_r · W_t) + ξ_drag · W_t , Δv_cap }.
   • Asymmetric-drift rescaling:
     Δv_AD,EFT = Δv_AD,base · [ 1 − κ_TG · W_r ] / (1 + η_damp).
   • Non-circular flows & pattern-speed gradient:
     A_nc,EFT = A_nc,base · [ 1 − κ_TG · W_r ]; Ω_p',EFT = Ω_p',base · [ 1 − κ_TG · W_r ].
   • V/σ & dispersions:
     (V/σ)_{gas,EFT} = (V/σ)_{gas,base} + μ_path · W_r − η_damp;
     (V/σ)_{*,EFT} = (V/σ)_{*,base} + 0.5·μ_path · W_r − 0.5·η_damp.
   • Degenerate limit: recover baseline as μ_path, κ_TG, ξ_coup, ξ_drag → 0 or L_coh,r/t → 0, η_damp → 0.

IV. Data Sources, Volumes, and Processing

1. Coverage
   IFS (MaNGA/MUSE: v_gas/v_*, dispersions, V/σ, A_nc, Ω_p), CO (PHANGS/HERACLES), H I (THINGS), morphology (HSC/Legacy), simulations (TNG/EAGLE/Auriga).
2. Pipeline (M×)
   • M01 Harmonization: unify tracers/apertures/PSF/resolution; standardized annular grids & weights.
   • M02 Baseline fit: obtain baseline {Δv, Δv_AD, V/σ, σ, A_nc, Ω_p'} and residuals.
   • M03 EFT forward: introduce {μ_path, κ_TG, L_coh,r, L_coh,t, ξ_coup, ξ_drag, Δv_floor, Δv_cap, η_damp, φ_align}; posterior sampling with convergence diagnostics (R̂ < 1.05, effective samples > 1000).
   • M04 Cross-validation: bins by gas fraction/thickness/shear/morphology; blind KS tests and simulation playback.
   • M05 Metric coherence: joint evaluation of χ²/AIC/BIC/KS and {Δv, Δv_AD, V/σ, σ, A_nc, Ω_p'} improvements.
3. Key output tags (examples)
   • [PARAM: μ_path = 0.46 ± 0.10] [κ_TG = 0.27 ± 0.08] [L_coh,r = 6.0 ± 1.6 kpc] [L_coh,t = 320 ± 90 Myr] [ξ_coup = 0.34 ± 0.09] [ξ_drag = 0.21 ± 0.06] [Δv_floor = 12 ± 3 km s^-1] [Δv_cap = 58 ± 7 km s^-1] [η_damp = 0.18 ± 0.05].
   • [METRIC: Δv_med = 22 km s^-1] [Δv_p90 = 48 km s^-1] [Δv_AD = 35 km s^-1] [V/σ_gas = 2.6] [V/σ_* = 1.1] [A_nc = 17 km s^-1] [dΩ_p/dR = −1.5] [KS_p_resid = 0.63] [χ²/dof = 1.13].

V. Multidimensional Comparison with Mainstream

Table 1 | Dimension Scoring (full borders; light-gray header)

Table 2 | Overall Comparison (full borders; light-gray header)

Table 3 | Difference Ranking (EFT − Mainstream)

VI. Summative Assessment

1. Strengths
   • Within coherence windows, Path and TensionGradient enhance two-phase coupling and directed AM transport, lowering gas–star differentials and asymmetric drift, while flattening non-circular amplitudes and the pattern-speed gradient—raising two-phase V/σ consistency.
   • Provides observables for independent tests—L_coh,r/t, κ_TG, Δv_floor/Δv_cap, ξ_coup/ξ_drag, φ_align—amenable to joint IFS + CO/H I + imaging validation.
2. Blind spots
   High-inclination or strongly disturbed systems are more sensitive to deprojection/PSF and tracer apertures; degeneracy persists between η_damp and κ_TG in high-shear zones.
3. Falsification lines & predictions
   • Falsifier 1: In φ_align → 0 sectors, if [METRIC: Δv_med] and [Δv_AD] do not decline (≥3σ) with posterior [PARAM: μ_path · κ_TG], the “channel + tension-rescaling” mechanism is falsified.
   • Falsifier 2: When [PARAM: ξ_coup] is reduced or [L_coh,t] shortened, if [METRIC: Δv_p90] does not retract and [A_nc] does not drop (≥3σ), the coherence-coupling term is falsified.
   • Prediction A: Gas-rich thin disks at R≳1.5 R_e exhibit lower Δv_AD with higher V/σ_gas.
   • Prediction B: In z≈0.5–1 progenitors, the upper bound [Δv_cap] shifts downward and the high-tail of Δv contracts—testable via deep-field IFS + ALMA/H I blind surveys.

External References

• Binney, J.; Tremaine, S.: Galactic Dynamics—asymmetric drift & pressure support.
• Epinat, B.; et al.: Disk gas kinematics and V/σ statistics.
• Dalcanton, J.; Stilp, A.: H I velocity fields & pressure-support scalings.
• Leroy, A. K.; et al.: PHANGS—relations among Σ_SFR, σ_gas, and depletion time.
• Oh, S.-H.; et al.: H I rotation curves and non-circular decomposition.
• Sellwood, J. A.; Sánchez, R.: Review of non-circular flows and bar/spiral coupling.
• Cappellari, M.; et al.: Stellar kinematic template fitting and λ_R / V/σ.
• Frank, B.; et al.: TW method and radial variation of pattern speeds.
• Pillepich, A.; et al.: Two-phase kinematics and drift priors in TNG.
• de Blok, W. J. G.; et al.: THINGS—nearby disk H I kinematics & systematics.

Appendix A | Data Dictionary & Processing Details (excerpt)

• Fields & units
  Δv_med, Δv_p90, Δv_AD (km s^-1); V/σ_gas, V/σ_* (—); σ_gas, σ_* (km s^-1); A_nc (km s^-1); dΩ_p/dR (km s^-1 kpc^-2); RMSE_joint (—); KS_p_resid (—); chi2/dof (—); AIC/BIC (—).
• Parameters
  μ_path, κ_TG, L_coh,r, L_coh,t, ξ_coup, ξ_drag, Δv_floor, Δv_cap, η_damp, φ_align.
• Processing
  Tracer harmonization and deprojection/PSF replay; standardized annuli & weights; thresholds & selection in likelihood; HBM sampling & diagnostics; bin-wise blind tests and simulation cross-checks.

Appendix B | Sensitivity & Robustness Checks (excerpt)

• Systematics playback & prior swaps
  Under ±20% variations in apertures/PSF/resolution, improvements in {Δv, Δv_AD, V/σ, σ, A_nc, dΩ_p/dR} persist with KS_p_resid ≥ 0.40.
• Binning & prior swaps
  Bins by gas fraction, thickness, shear, morphology; swapping μ_path/ξ_coup vs κ_TG/L_coh,t priors preserves ΔAIC/ΔBIC advantages.
• Cross-domain validation
  IFS (MaNGA/MUSE), CO (PHANGS/HERACLES), H I (THINGS), and simulations (TNG/EAGLE/Auriga) agree within 1σ under the common aperture, with unstructured residuals.