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Combining data over a period of 3 years obtained at UKIRT, astronomers in 2008 have produced an image containing over 100,000 galaxies (Figure 05-06b). Many of the faint red objects in the background (against a relatively nearby spiral galaxy) are massive galaxies at distances of over 10 billion light-years. | |||
Figure 05-06a ERO |
Figure 05-06b Infrared Galaxies [view large image] |
Figure 05-06c Hot DOG |
In August 2009 the rejuvenated Hubble Telescope took an infrared deep field image (Figure 05-07a). It shows many small galaxies with redshift of up to 8.5 corresponding to 13.1 billion light years from us or about 600 million years after the Big Bang. Their size and mass are about 1/20 and 1/100 of those of the Milky Way respectively. Although detected in the near infrared region of the spectrum, they are intrinsically blue (before the redshift) - meaning that they may be deficient in heavier elements, i.e., made with primordial matter, and as a result, quite free of | ||
Figure 05-07a Furthest Galaxies [view large image] |
Figure 05-07b Furthest Cluster of Galaxies |
the dust that reddens light through scattering. The discovery of these galaxies so near the beginning of the reionization epoch (Figure 05-07c) with the seemingly insufficient radiation output raises the possibility |
One possibility is that there have been a large population of unseen small galaxies working together to do the job. NASA is now pursuing a tactic which uses high-mass cluster of foreground galaxies as cosmic zoom lenses to see further (with the existing Hubble telescope). Meanwhile in Chile, ALMA will ioin the hunt for distant galaxies starting from summer 2013. The 6.5-meter JWST (to be launched in 2018) will image the faint, primitive bodies that Hubble can only glimpse (see Hubble Ultra-Deep Field, Figure 05-07d). | ||
Figure 05-07c Reionization (2013 Version) [view large image] |
Figure 05-07d HUDF [view large image] |