2014/10/31 by Pierre Fleury, Cyril Pitrou, Jean-Philippe Uzan +1
Mathematics · Physics and Astronomy · #Anisotropy #Astrophysical Phenomena and Observations #Astrophysics #Classical mechanics #Cosmology #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gamma-ray bursts and supernovae #Geodesic #Geodesics in general relativity #Geometry #Homogeneous #Luminosity distance #Mathematical analysis #Mathematical physics #Mathematics #Null (SQL) #Optics #Physics #Quantum mechanics #Redshift #Rotation (mathematics) #Solving the geodesic equations #Spacetime #Statistical physics #Universe #astro-ph.CO #gr-qc
paper · pdf · doi:10.1103/physrevd.91.043511
published as Phys. Rev. D 91, 043511 (2015) · 12 pages, no figure; v3 matches published version, except a minor typo in Eqs. (4.8), (4.10), now corrected
openalex publication_date 2015/02/10 · arxiv created 2015/03/11 · arxiv updated 2015/03/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
This article proposes a comprehensive analysis of light propagation in an anisotropic and spatially homogeneous Bianchi I universe. After recalling that null geodesics are easily determined in such a spacetime, we derive the expressions of the redshift and direction drifts of light sources; by solving analytically the Sachs equation, we then obtain an explicit expression of the Jacobi matrix describing the propagation of narrow light beams. As a by-product, we recover the old formula by Saunders for the angular diameter distance in a Bianchi I spacetime, but our derivation goes further since it also provides the optical shear and rotation. These results pave the way to the analysis of both supernovae data and weak lensing by the large-scale structure in Bianchi universes.