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A Search for HI Absorption in the Radio Spectra of the Quasi-Stellar Objects 4C 05.34 and PKS 0237-23

Published online by Cambridge University Press:  25 April 2016

B.A. Peterson ,
J.D. Murray  and
A.E. Wright
B.A. Peterson*
Affiliation:
Division of Radiophysics, CSIRO, Sydney
J.D. Murray
Affiliation:
Division of Radiophysics, CSIRO, Sydney
A.E. Wright
Affiliation:
Division of Radiophysics, CSIRO, Sydney
*
*Present address – Anglo-Australian Observatory, Sydney.
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Extract

The ratio of the mass density in visible galaxies to the upper limit for the HI mass density determined from the lack of continuous Ly-α absorption in QSO spectra is 3 × 104. Thus, if galaxies form by condensation from an intergalactic medium, the process must be extremely efficient. Although no absorption due to a continuous distribution of intergalactic HI has been detected, many QSOs have been discovered that have absorption lines in their spectra, which have redshifts very different from the emission lines, and may be produced in clouds of integalactic HI. As would be expected if this were the case, the proportion of QSOs with absorption lines in their spectra is greatest for those which have large emission line redshifts. Another possibility, especially for those absorption lines in redshift systems with Zabs nearly equal to Zem , is that the absorption lines are produced in clouds surrounding the QSO.

Type
Contributions
Information
Publications of the Astronomical Society of Australia , Volume 2 , Issue 6 , October 1975 , pp. 365 - 366
Copyright
Copyright © Astronomical Society of Australia 1975

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