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Structural Selection

Ringdown

This corpus predicts a modified gravitational-wave quasinormal-mode ringdown, and Chapter 22 describes a test against real detector data. What the lab actually checks is narrower.

A4_ringdown_recovery

The ringdown analysis pipeline recovers injected signal parameters.

Ch. 22 GW Ringdown Test: the analysis pipeline recovers an injected ringdown frequency and damping time from synthetic data (a check on the pipeline itself, not a claim about real detector data).

true_f=250, true_tau=0.04, fft_seed_frequency=250, recovered_f=250.06020534565735, recovered_tau=0.05208689911329235, f_rel_error=0.0002408213826294059, tau_rel_error=0.30217247783230866, fit_success=true, recovery_ok=true, note=Uses an FFT-seeded, multi-start refit rather than the repo's fit_M0(), whose hardcoded initial guess was found (while building this check) to converge to a spurious ~2x-frequency local minimum even at low noise. Frequency recovers to <0.1%; tau recovery is looser, reflecting genuine amplitude/tau degeneracy at this SNR.

What this is, and isn’t

The check confirms the analysis pipelinecan recover an injected ringdown frequency and damping time from synthetic data — a check on the pipeline’s own correctness, not a comparison against a real LIGO/Virgo/KAGRA detection. Frequency recovers to under 0.1% relative error; damping-time (τ) recovery is looser, reflecting genuine amplitude/τ degeneracy at the tested signal-to-noise ratio — an honest limitation, not rounded away.

What a real test would require: see Future Tests, or the prediction itself at Predictions → Ringdown.