Scenario · engineered-IMBH feasibility · chains four tools

Paper E, Walked: Envelope to Adjudication

Four tools trace Paper E’s argument spine in order: a Monte Carlo sweep of the surviving orbital envelope against stellar flybys, a single-point drill-down at a radius chosen from that envelope, the Bondi-supply-vs-waste-heat ordering that decides which constraint actually binds, and the Bayes-factor adjudication that prices today’s silence. The chain ends where the paper does: the null is currently favored, and the framework says what would move it.

No backend · No tracking · Works offline · v1.0 · 2026-07-18
This walkthrough uses the site’s fiducial velocity dispersion σ = 18.2 km/s (the tools read it from the shared measurements.js compilation). Paper E’s own reference run adopts the cluster’s central-region value, σ = 21 km/s, and the difference between the two is a documented offset rather than a bug; see the fiducial note on each flyby tool’s page for the full accounting.
⚙ Pick where in the envelope the swarm sits

Both options share the same flyby-hazard sweep, the same fuel budget, and the same evidence adjudication — only the drill-down radius in Step 2 changes. That is itself a finding of Paper E §2.5: the fuel supply and today’s Bayesian evidence do not depend on where within the surviving envelope a hypothetical installation sits.

01
flyby-survival-simulator · Paper E §2.4 · Monte Carlo envelope sweep
Do stellar flybys ever bind the envelope?

This sweep runs the impulsive-diffusion Monte Carlo across the full radius range at once: impact parameters from the gravitationally focused encounter rate, velocities from a Maxwellian at dispersion σ, masses from the perturber mass function, and survival defined as eccentricity walking to the orbit-crossing threshold. The mass function carries a mass-segregated heavy-remnant tail (10 M☉ stellar BHs at the fiducial 1% number fraction, the fbh deeplink here), and that tail sets the floor: the median survival time is ≈3×10⁶ yr, roughly flat from 10⁻³ to 4×10³ AU, because the per-encounter kick variance and the encounter rate scale inversely with radius and their product cancels. This supersedes the stars-only ≈3×10⁹ yr floor Paper E first reported (recover it with fbh=0). The floor stays well above the 10⁶ yr passive-safety criterion, so flybys still never set the outer boundary; they are a trim budget, not a survival requirement.

Open Flyby Survival Simulator → ✦ Speculative engineering Orbital mechanics established
Step payoff
The operative outer boundary is the cluster stripping radius (§2.3), not the flyby hazard. The sweep exists to confirm that everything inside the stripping radius is dynamically quiet — a conservative floor, since it omits the adiabatic protection that lengthens survival further at depth.
02
flyby-survival · Paper E §2.2–2.3 · single-point drill-down
Pick a radius, read the full survival budget

Drilling into one radius from the swept envelope gives the encounter rate, mean wait time, penetrating fraction, orbital period, and influence radius that the sweep view compresses away. At the deep-swarm radius the structure sits inside the fueled boundary set by tidal stress and orbit stability (§2.2); at the outer-envelope radius it sits at the tidal-truncation edge (§2.3), the last radius the cluster’s own field does not eventually strip. Both radii return the same conservative diffusion floor family — the difference is in the encounter statistics, not the survival verdict.

Open Flyby Survival → ✦ Speculative engineering Encounter physics established
Step payoff
Wherever in the envelope a swarm sits, the encounter statistics stay survivable. The binding question moves on from dynamics to power: can the installation get fuel, and can it hide the heat.
03
imbh-fuel-budget · Paper E §2.7 & §3.1 · Bondi supply vs. waste-heat ceiling
Which constraint actually binds: fuel or heat?

Bondi accretion from ω Cen’s measured intracluster medium (ne ≈ 0.23 cm⁻³) funds an extractable power roughly two orders of magnitude above the waste-heat ceiling: the entropy-transport floor of Appendix A.3, adopted here at 1−fsink ≈ 10⁻⁴, caps the computation an installation can run without its own radiated heat exceeding the JWST mid-infrared point-source limit. The ordering is the paper’s central engineering result: for a fiducial 2×10⁴ M☉ hole, supply never binds and thermal concealment does. That ordering reverses for stellar-mass holes in the same environment, which is itself part of why the hypothesis family selects IMBHs.

Open IMBH Fuel Budget → ✦ Speculative engineering Bondi/Eddington physics established
Step payoff
The transport floor adopted here (1−fsink ≈ 10⁻⁴) is an engineering estimate, not a derivation from first principles; Paper E §6.1 states what a real derivation needs and how the headline result moves if the floor is looser or tighter.
04
bayes-factor-router · Paper E §5 · adjudication on 2026 data
Today's verdict, and what would move it

Feeding the hierarchical Bayesian framework’s per-channel result into the same router used across the ChainGraph evidence chains gives the paper’s headline number directly: ln K = −0.29 (2·ln K = −0.58) for the engineered hypothesis against the best astrophysical null, on the pre-registered Jeffreys/Kass–Raftery action bands. That routes to supports null hypothesis — waste heat is presently the only live evidence channel, and the current silence mildly favors the quiescent-IMBH null. Deeper mid-infrared photometry tightens the Pcomp ceiling linearly (§3.1); the regulation-signature and relic-drainage channels are conditional and forecastable, not yet live (§3.2–3.4).

Open Bayes Factor Router → Jeffreys / Kass–Raftery, peer-reviewed
Step payoff — the chain closes
The adjudication is instrument-agnostic: the router only ever sees a Bayes factor, never an architecture. Steps 1–3 establish that an engineered installation could survive and could be fueled anywhere in the surviving envelope; Step 4 shows that surviving and being fueled is not the same as being detected — the present data mildly disfavor the hypothesis, and the framework says exactly which future observation would change that.
⚖ Why these four tools are the paper's spine

Paper E runs in one direction: constraints on where infrastructure could persist (§2) produce forward-modeled observables (§3) that feed an adjudication engine (§4) exercised on real data (§5). The four tools chained here are exactly that direction, in order: the envelope sweep and the single-point drill-down are §2, the fuel-budget ordering bridges §2.7 into the waste-heat floor of §3.1, and the router is §5’s adjudication in miniature.

What the chain does not show is more informative than what it does: neither radius choice changes the fuel ordering or the adjudicated verdict, because those two results are properties of the ambient medium and of today’s data, not of the hypothesized architecture. That separation is itself one of Paper E’s findings — the feasibility envelope is a prior on where a system could sit, and the evidence is a likelihood that does not care where inside that prior it sits.

For the full derivation, including the Appendix A.3 transport-floor accounting and the §6.1 limitations on the drainage-timescale estimate, see Paper E: Engineered Intermediate-Mass Black Hole Systems (PDF). For the campaign this paper's adjudication framework serves, see the companion chain Scenario — Five Ways to Look for ET.

EPISTEMIC TIERS: Established = peer-reviewed physics within the standard formulation. Debated = active disagreement in the published literature. Theoretical = published framework, awaiting decisive observation. ✦ Speculative = published conjecture, no strong empirical support yet.