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See here for a study of a group of galaxies
at a redshift 1.5: http://xxx.lanl.gov/abs/astro-ph/0205239 Someday soon, studies such as these and much deeper will become commonplace. They will have to be if we are to understand the history and evolution of galaxies. Note that they find that the bulk stellar populations must be older than about 3 billion years. This leaves about 1 billion years for those galaxies' formation, for today's best estimates of the cosmological parameters. No mention of a 10 billion year old stellar population at this redshift, though. Note, too, that the elliptical galaxy's surface brightness essentially scales to what it should be, if one were to redshift a nearby elliptical of a similar mass (a (1+z)^4 dimming), allowing for the expected luminosity evolution of the stellar population, given a formation epoch at z > 3 (probably more like z > 5). happy reading.... |