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Updated: Aug 3, 2026

Measurement of X-ray Beam Coherence along Multiple Directions Using 2-D Checkerboard Phase Grating
Published on: October 11, 2016
Redshift survey with multiple pencil beams at the galactic poles
A S Szalay1, T J Broadhurst, N Ellman
1Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA.
Abstract:
Observations of the large-scale structure of the universe suggest inhomogeneities on scales between 100h-1 and 150h-1 Mpc (where h approximately 0.5-1 is the Hubble constant in units of 100 km.s-1.Mpc-1; 1 pc = 3.09 x 10(16) m). A deep redshift survey with a "pencil-beam" geometry of galaxies at the galactic poles indicated strong clustering, with a provocative regularity at 128h-1 Mpc [Broadhurst, T. J., Ellis, R. S., Koo, D. C. & Szalay, A. S. (1990) Nature (London) 343, 726-728]. Using newly acquired data, we demonstrate how multiple deep probes overcome most of the statistical problems associated with single pencil beams. Our results from cross correlations of multiple pencil beams, containing over 1200 galaxies, indicate that the strong peak in the power spectrum results from structures of large transverse size, in agreement with our original conjecture. We also discuss the sensitivity of pencil-beam surveys to the topology of large-scale structures and compare them with sparsely sampled wide-angle local surveys.
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