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Unformatted text preview: QSO. A sample of the Lyman α forest is given in Fig. 1 of Young et al. 1982 (ApJ 252, 10, courtesy of the AAS): The strong broad emission feature is Lyman α at the QSO redshift z =1.899. Identification of the narrow features as the same transition is supported by the gross asymmetry on either side of the emission peak. Note that the density of absorption features changes with redshift (wavelength). Adopting some cosmological model, this gives the time evolution of the absorbers. It is traditional (though by now somewhat misleading) to identify distinct absorption features as physical clouds. These clouds either are or are imbedded in the IGM. What can we tell about their properties?...
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This note was uploaded on 11/10/2011 for the course AST AST1002 taught by Professor Emilyhoward during the Fall '10 term at Broward College.
- Fall '10