W.M. Keck Observatory | 2014 Oct 16
'CT Scan' of Distant Universe Reveals Cosmic Web in 3D
Max Planck Institute for Astronomy | 2014 Oct 16
A team led by astronomers from the Max Planck Institute for Astronomy has created the first three-dimensional map of the 'adolescent' Universe, just 3 billion years after the Big Bang. Applying a new technique analogous to x-ray computer-tomographic (CT) imaging used in medicine, the researchers measured the light from a dense grid of distant background galaxies probing the Universe from multiple locations, and then combined the data to construct a 3-D map of the intervening matter. This map, millions of light years across, provides a tantalizing glimpse of large structures in the 'cosmic web', which forms the backbone of cosmic structure.
On the largest scales, matter in the Universe is arranged in a vast network of filamentary structures known as the 'cosmic web', its tangled strands spanning hundreds of millions of light years. Dark matter, which emits no light, forms the backbone of this web, which is also suffused with primordial hydrogen gas left over from the Big Bang. Galaxies like our own Milky Way are embedded inside this web, but fill only a tiny fraction of its volume.
Now a team of astronomers led by Khee-Gan Lee, a post-doc at the Max Planck Institute for Astronomy, has managed to create a three-dimensional map of a large region of the far-flung cosmic web nearly 11 billion light years away, when the Universe was just a quarter of its current age. Similar to a medical CT scan, which reconstructs a three-dimensional image of the human body from the X-rays passing through a patient, Lee and his colleagues reconstructed their map from the light of distant background galaxies passing through the cosmic web's hydrogen gas. ...
Lyman-alpha Forest Tomography from Background Galaxies:
The First Megaparsec-Resolution Large-Scale Structure Map at z>2 - Khee-Gan Lee et al
- arXiv.org > astro-ph > arXiv:1409.5632 > 19 Sep 2014