Demo V · Accretion Chain
Four distinct channels feed ω Cen's IMBH — from individual tidal captures through full disruptions to the accumulated growth history spanning billions of years. The current JWST silence constrains them all.
Choose an accretion regime
Each scenario emphasises a different feeding channel dominant at different epochs in OC's history.
The loss cone is the region of orbital phase space where a star's angular momentum is low enough that it will pass within the tidal radius of the IMBH. Two-body relaxation within the cluster continuously scatters stars into this cone. The resulting capture rate — dN/dt per stellar type — depends on the IMBH mass, stellar density ρ(r), velocity dispersion σ, and the tidal radius r_T = R★ (M_BH/M★)^(1/3).
For ω Cen's IMBH, the natural capture rate spans a wide range across stellar populations. Main-sequence captures dominate by number but release relatively little energy. Neutron star EMRIs are rare but release the most energy per event and produce detectable gravitational wave chirps. White dwarf tidal captures sit between. This tool spans the full Häberle–Bañares-Hernández tension band so you can compare rates at both constraint extremes.
A star that enters the loss cone on a near-radial orbit reaches the tidal disruption radius — where the BH's tidal force overwhelms stellar self-gravity — before it can be captured intact. The star is shredded. Roughly half the debris escapes; the other half circularises into an accretion disk that feeds the IMBH over months to years, producing a luminous flare. For ω Cen's IMBH, TDEs are the dominant mass-growth channel for main-sequence stars.
The distinction between full TDE and tidal capture (step 1) depends on the star's penetration parameter β = r_T / r_pericenter. At β < 1 the star survives as an EMRI; at β > 1 it is disrupted. The borderline — partial TDEs — strips the envelope and leaves a compact remnant on an eccentric orbit, potentially a recurrent source. The tool covers all three outcomes for MS, WD, and NS star types.
Chen et al. (2025) pointed JWST NIRCam at ω Cen's core and found nothing. No near-infrared excess from an accretion disk, no hot dust emission, no central point source above the stellar background. This null result sets an upper limit on the current Eddington fraction: ṁ/ṁ_Edd ≪ 1. For a ~10,000 M☉ IMBH, even a faint Seyfert-level accretion rate would be detectable — the IMBH is either completely starved of gas, or its emission is absorbed and re-emitted at wavelengths JWST did not observe.
This tool lets you set the accretion efficiency η, ambient gas density, and sound speed to find the maximum allowed Bondi-Hoyle accretion rate consistent with the JWST non-detection. The constraint is tight: the environment within ~0.01 pc of the IMBH must be essentially evacuated. This silence is the primary observational tension with the IMBH hypothesis under standard accretion models — and the starting point for both the gas-starvation null hypothesis and the OCS managed-feeding speculation.
The IMBH did not arrive at its current mass in a single event. The growth history reconstructs how the black hole accumulated mass over the cluster's ~12 Gyr lifetime, combining a seed mass from runaway stellar collisions or direct collapse, episodic TDE-driven growth during the cluster's dense early phase, merger contributions from globular cluster in-fall, and the long quiescent period we observe today.
The tool produces a growth curve showing mass vs. time under adjustable channel weights. The current JWST non-detection (step 3) constrains the late-time accretion rate to essentially zero, while the Häberle lower bound constrains the integrated mass. Together these bracket the allowed growth history: almost all growth must have happened in the first ~4–6 Gyr, with the hole effectively idle since ~z ~ 1.
Four tools, one story: the IMBH ate voraciously during its first few billion years — mostly through tidal disruptions and stellar captures as the primordial dense nucleus relaxed — then went quiet. The JWST non-detection constrains the present Eddington fraction to well below 10⁻⁵, consistent with a gas-starved environment that has had its inner reservoir swept clean over Gyr timescales.
From an OCS perspective, this silence is either the natural end-state of cluster dynamics (the mainstream interpretation) or the signature of a Phase 3+ civilisation that has already managed its feeding environment: prograde brown-dwarf captures, sub-Eddington accretion, all energy routed inward through the ISCO with zero radiative waste. Both scenarios predict the same JWST null result. The growth history chain is the tool that distinguishes them in principle: a managed feeding history will show a resumption of mass growth in the last ~1–2 Gyr as the feeding program begins, while natural quiescence shows a monotonically declining rate since z ~ 2. This distinction requires mass measurements better than ~100 M☉ precision — achievable, in principle, with next-generation astrometry or LISA chirp timing.