Angular and luminosity distance observables
For transparent geometrical photon propagation in FLRW cosmology, angular diameter distance is D_A=D_M/(1+z), and luminosity distance is D_L=(1+z)D_M=(1+z)²D_A.
Key knowledge
For transparent geometrical photon propagation in FLRW cosmology, angular diameter distance is D_A=D_M/(1+z), and luminosity distance is D_L=(1+z)D_M=(1+z)²D_A. A small observed angle relates to proper transverse size at emission through D_A. Bolometric luminosity and received bolometric flux satisfy F=L/(4πD_L²).
Values and equations
D_A=D_M/(1+z); D_L=(1+z)D_M=(1+z)²D_A; F=L/(4πD_L²)
- D_A,D_L,D_M
- angular diameter, luminosity and transverse comoving distances m
- z
- cosmological source redshift 1
- L
- source bolometric luminosity W
- F
- received bolometric energy flux W m⁻²
Conditions and scope
- Use the same source redshift and transverse comoving distance convention, geometrical optics and transparent propagation conserving photons.
- Extinction, lensing and selection affect actual inference; finite-band observations need the appropriate spectral and K corrections. A lens-to-source angular diameter distance is not generally the difference of two observer-to-object angular diameter distances.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Read the distinct angular and luminosity definitions, redshift factors, bolometric flux relation and spectral-band qualification. Retained no dated numerical cosmology or magnitude zero-point assertion.
2026-10-10 · Independent AI editorial review: All44 exact root-authored compact records, equations/variable units/conditions and140 origin edges accepted after independently reading final6/18 with bounded primary bodies and matching prior38/122 scientific fingerprints unchanged. Exact claim/edge review is distinct from combined inventory scope and separate CLE26 approval; no entire cited books or old-corpus experimental revalidation is asserted. Receipt: cosmos-completion-independent-content-and-inventory-review.1.
Entry details
Permanent link to this entry ↗- Record identity
- uni-cosmos-flrw-distance-observables
- Revision
- core.1
- Structured reference record
- University core expansion