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Properties of high-redshift Lyman-alpha clouds. I - Statistical analysis of the Schneider-Schmidt-Gunn quasarsTechniques for statistical analysis of the Lyman-alpha forest in high-redshift quasars are developed, and applied to the low-resolution (25 A) spectra of 29 of the 33 quasars in the Schneider-Schmidt-Gunn sample. We extrapolate each quasar's continuum shortward of Lyman-alpha emission, then consider each spectral bin of each quasar to be an (approximately) independent measurement of the absorption due to the Lyman-alpha clouds. With several thousand such measurements thus available, we can obtain good determinations of some interesting properties of clouds in the redshift range 2.5-4.3 without actually resolving any single cloud. We find that the mean absorption increases with z approximately as a power law (1 + z) exp (gamma + 1) with gamma = 2.46 +/- 0.37. The mean ratio of Lyman-alpha to Lyman-beta absorption in the clouds is 0.476 +/- 0.054. We also detect, and obtain ratios, for Lyma-gamma, delta, and possibly epsilon.
Document ID
19930071235
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Press, William H.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Rybicki, George B.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Schneider, Donald P.
(Inst. for Advanced Study Princeton, NJ, United States)
Date Acquired
August 16, 2013
Publication Date
September 1, 1993
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 414
Issue: 1
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
93A55232
Funding Number(s)
CONTRACT_GRANT: NAG5-1618
CONTRACT_GRANT: NSF PHY-91-06678
Distribution Limits
Public
Copyright
Other

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