1997/02/25 by J. Richard Bond, Bond, J. Richard, Dmitry Pogosyan +3
Environmental Science · Physics and Astronomy · #Astrophysics (astro-ph) #Climate variability and models #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Scientific Research and Discoveries #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9702212
3 pages with 1 figure, uses sprocl.sty, to appear in the Proceedings of the 18th Texas Symposium on Relativistic Astrophysics, ed. A. Olinto, J. Frieman and D. Schramm (World Scientific, Singapore, 1997)
arxiv created 1997/02/25 · openalex publication_date 1997/02/25 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The (large angle) COBE DMR data can be used to probe the global topology of our universe on scales comparable to and just beyond the present ``horizon''. For compact topologies, the two main effects on the CMB are: [1] the breaking of statistical isotropy in characteristic patterns determined by the photon geodesic structure of the manifold and [2] an infrared cutoff in the power spectrum of perturbations imposed by the finite spatial extent. To make a detailed confrontation of these effects with the COBE maps requires the computation of the pixel-pixel temperature correlation function for each topology and for each orientation of it relative to the sky. We present a general technique using the method of images for doing this in compact hyperbolic (CH) topologies which does not require spatial eigenmode decomposition. We demonstrate that strong constraints on compactness follow from [2] and that these limits can be improved by exploiting the details of the geodesic structure for each individual topology ([1]), as we show for the flat 3-torus and selected CH models.