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An observational constraint on the existence of proto-superclusters at Z = 3.3

  • Subrahmanyan, Ravi
  • Swarup, G.
Publication Date
Jun 01, 1990
Raman Research Institute Digital Repository
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Observations have been conducted using the Ooty Radio Telescope in order to place constraints on the evolutionary scenario leading to the formation of the present day superclusters. The experiment attempted to detect 21 cm emission from massive neutral hydrogen condensates at a redshift of z = 3.3. In an Einstein de-Sitter universe with baryon density Omega = 0.05, about ten condensates were expected in the volume surveyed if superclusters, having H I masses of 5 x 10 to the 15th solar masses, were the first objects to separate out of the Hubble expansion. The sensitivity of the experiments described here rules out the existence of these condensates at z = 3.3 unless their lifetimes are less than one-tenth the dispersion in their epoch of formation or the proto-superclusters subtend angles greater than 6 arcmin. The result indicates that superclusters form at z greater than 3.3 if indeed they were the first objects to condense out of the Hubble flow.

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