> but since we're talking about high-redshift objects, I think that the following paper is a must-read:
>
> http://lanl.arxiv.org/abs/astro-ph/0310808
>
> This paper explains how, in the current `Lambda-CDM concordance' model for the universe, which is observationally well-constrained (e.g. by WMAP), z = 1.46 is an important redshift. If you manage to observe an object with z > 1.46, you're seeing light from an object that is receding from us faster than the speed of light. It's beyond a portion of the universe called the `Hubble Sphere'.
>
> Yes, it's possible for objects to have an apparent velocity of recession greater than light. Even much greater. And no, this doesn't violate relativity. That's what the paper is all about. It also points out that many textbooks and popular accounts of cosmology are filled with inaccuracies and misconceptions about the expansion of the universe, including assertions that nothing can appear to recede from us faster than light. It's well worth a read.
That paper will take a little while to digest ;-) but in the meantime here's a relatively easy quasar that fits the criteria of z > 1.46 (i.e. apparently receding faster than the speed of light).
Ton 490
10 13 53.4 +24 49 16
V = 15.4
18" (2/23/06): it was easy to track down this distant quasar as it is located close west of an attractive string of three stars with the brightest star at the SSE end a delicate, equal mag double (h477 = 10.3/10.3 at 4"). Ton 490 appeared as a star object between mag 15 and 15.5 (estimate). It could easily be glimpsed at 257x with a brighter mag 14.2 star 1' south. With a redshift of z = 1.636 this high luminosity quasar is located at a distance of ~9.5 billion light years.
Steve
-- Who's observing/imaging where? http://observers.org/OI-calendar/ GSSP is coming, July 10-14 http://www.goldenstatestarparty.org TAC's imaging mailing list: http://groups.yahoo.com/group/TAC-Imaging/Received on Sun Feb 7 22:44:40 2010
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