Line-of-sight Jeans projection and boundary closure
Research context
research method · conditional · As of 2026-10-10
A projected dispersion averages line-of-sight moments through the tracer system.
Key knowledge
A projected dispersion averages line-of-sight moments through the tracer system. The anisotropy factor is inside the radial integral, so a projected profile alone generally cannot separate mass from anisotropy. The boundary condition at large radius is part of the model.
Values and equations
Σ(R) σlos^2(R)=2 integral_R^infinity [1-β(r)R^2/r^2] ν(r)σr^2(r) r dr/sqrt(r^2-R^2)
- Σ
- Projected tracer number density m^-2
- R,r
- Projected and spherical radius m
- σlos,σr
- Line-of-sight and radial dispersion m s^-1
- ν
- Tracer number density m^-3
- β
- Anisotropy 1
Conditions and scope
- Σ is projected tracer density; consistently account for selection and measurement covariance.
- The displayed integral assumes spherical symmetry and σθ=σφ, no mean rotation and convergent outer integrals.
Sources · 2
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Dwarf-galaxy masses using the Jeans equation: Projected surface-density and line-of-sight dispersion integrals (selected source body inspected). The Jeans equations: Spherical nonrotating moment equation, anisotropy and boundary integral (selected source body inspected).
2026-10-10 · Bounded source check of the recorded statement and conditions. This does not certify a unique physical model, reproduce the cited study or replace independent branch review.
Entry details
Permanent link to this entry ↗- Record identity
- research-earth-jeans-projection
- Revision
- research.1
- Structured reference record
- Postgraduate & research reference