Quote:
Originally Posted by Amber Robot
In the spectra of quasars there exist absorptions from neutral hydrogen at redshifts that range from the redshift of the quasar itself to lower values. If the redshift from a quasar is not cosmological, then none of the redshifts of the intervening hydrogen can be cosmological either.
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Quote:
Originally Posted by rtomes
Your points are taken, and I do not expect to satisfy them. However if Arp is right, I think it possible that the hydrogen is associated with the nearby quasar and has an intervening redshift because it is being party influenced by the quasar and partly by the galaxy as to its red shift.
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I call to your attention a little known paper, which was eventually published in the Publications of the Yunnan Observatory 90(2): 16-21, 2002 (or so I assume since the titles are the same, although only Qin & Liang authored the Yunnan version):
Evidence consistent with the cosmological interpretation of quasar redshifts, Qin, Xie, Zhen & Liang, 2000.
Abstract: In this letter, the old issue of whether redshifts of quasars are of cosmological origin is investigated. We make a plot of absorption redshifts versus emission redshifts for quasars with large amounts of data. Our study shows that, almost all absorption redshifts are smaller than the corresponding emission redshifts. The relation between the absorption and emission redshifts predicted by current cosmological models is well obeyed. The result confirms that redshifts of quasars are indeed distance indicators. It might be the most obvious evidence found so far to be consistent with the cosmological interpretation of quasar redshifts.
You can see from the paper that the higher redshift quasars, which are at larger distances in the standard models, have more Lyman-alpha absorption lines than to lower redshift (closer) quasars. Furthermore, it is very rare to find an absorption line at higher redshift than the quasar, and in all such cases, the difference is very small, consistent with the higher redshift absorber being associated with the host galaxy. If we simply assume that the absorber is somewhere between the quasar and us, surely a reasonable assumption, then it is indeed hard to avoid the conclusion that the quasar redshift is a valid indicator of cosmological distance, as opposed to being in any way intrinsic to the quasar.
You suggest that the redshift is always smaller because the absorber is influenced in some way by the quasar or the host galaxy. Do you have any specific mechanism(s) to suggest?