In the Dark

I found this video via a web page describing the FastSound project, which is surveying galaxies in the Universe which are at such a huge distance that we are seeing them as they were over nine billion years ago. Using the Subaru Telescope‘s impressive new Fiber Multi-Object Spectrograph (FMOS). This project is “work in progress”. The survey so far contains only 1,100 galaxies, but while that is small by the standards of a modern redshift survey, and will in fact still only comprise about 5000 galaxies when complete, what is amazing about it is that the galaxies are at such enormous distances. Even using a telescope with an 8.2 metre primary mirror, this survey will take another year or so to be completed.

A survey of a representative region of the Universe at such high redshift allows astrophysicists to test theories of the growth of the large-scale structure of the Universe. In the standard cosmology, these form by a process of gravitational instability: small irregularities in the distribution of matter get amplified by the action of gravity to become large structures such as galaxies and galaxy clusters. Comparing the level of clustering at early times with that observed around us today allows us to check whether this growth matches theoretical predictions. There should be much less clumpiness earlier on if the theoretical picture is right.

I began my PhD DPhil at the University of Sussex in 1985, working on the large-scale structure of the Universe. Coincidentally, the largest redshift survey available at that time, the CfA1 Survey, also contained 1,100 galaxies – as displayed in the famous “stick man map”:

The galaxies mapped out in that survey, however, are all (relatively speaking) in our back yard: none is further than a few hundred million light years away…

This entry was posted on August 14, 2013 at 12:40 pm and is filed under The Universe and Stuff with tags CfA survey, Cosmology, FastSound, large-scale structure of the Universe, Subaru. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.