How does the observed hot-baryon distribution across halos differ from that required by the baryon-census and pressure-support budgets?

Scope

In scope

A programme container organizing galaxy-hot-halo baryon inventories and cluster-ICM thermal/non-thermal pressure-support evidence, with discrimination delegated to two L1 children.

Out of scope

Not an automatic paper-mapping target; redistribution by feedback or environment changes the inventory and is not a steady pressure-support term; no field-wide consensus authority.

Why it matters

Preserves a bounded shared programme while separating the previously over-broad hot-halo question into auditable galaxy and cluster decision surfaces.

Competing explanations

• After selection and measurement systematics are corrected, observed hot phases close the baryon census and pressure budgets
• Low-surface-brightness, multiphase, or beyond-aperture gas leaves the inventory incomplete
• Turbulence, bulk motions, cosmic rays, or magnetic fields supply a significant non-thermal pressure term

Discriminating observables

• Joint X-ray emission, tSZ, and absorption-line gas fractions relative to the cosmic baryon fraction
• Hydrostatic masses relative to weak-lensing or dynamical masses
• Radial gas-fraction and pressure-support profiles across halo mass

Blockers

• Galaxy and cluster samples, radial definitions, and mass calibrations are not directly interchangeable
• Thermal, non-thermal, and projection systematics have limited cross-scale comparability
• Cross-regime matching from galaxies through groups to clusters