2009/06/30 by Alnadhief H. A. Alfedeel, Alnadhief A. H. Alfedeel, Charles Hellaby · 24 citations
Physics and Astronomy · #Advanced Differential Geometry Research #Apparent horizon #COSMIC cancer database #Cosmological model #Cosmology #Cosmology and Gravitation Theories #Differential geometry #Horizon #Invariant (physics) #Metric (unit) #Relativity and Gravitational Theory #astro-ph.CO #gr-qc
paper · pdf · doi:10.1007/s10714-010-0971-y
published in General Relativity and Gravitation 42(8), 1935-1952 (Springer Science+Business Media) · latex, 16 pages, Revision has minor changes due to referee's comments.
arxiv created 2010/03/12 · openalex publication_date 2010/04/07 · arxiv updated 2014/11/20 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We consider the spherically symmetric metric with a comoving perfect fluid and non-zero pressure -- the Lemaitre metric -- and present it in the form of a calculational algorithm. We use it to review the definition of mass, and to look at the apparent horizon relations on the observer's past null cone. We show that the introduction of pressure makes it difficult to separate the mass from other physical parameters in an invariant way. Under the usual mass definition, the apparent horizon relation, that relates the diameter distance to the cosmic mass, remains the same as in the Lemaitre-Tolman case.