EWASS: 4,000 Early Galaxies Discovered in 3D Map of Infant Universe

bystander · Post by **bystander** » Wed Apr 04, 2018 2:59 pm

Astrophysicists Map the Infant Universe in 3D and Discover 4,000 Early Galaxies
European Week of Astronomy and Space Science | 2018 Apr 03

A map of the cube of spacetime covered in the new survey, showing the distance to the galaxies in billions of light years. The positions of the 4,000 galaxies appear as circles. The colours represent the degree of redshift seen, with the bluer circles indicating galaxies nearer to the Earth, and so less redshifted. Green, yellow, orange and red circles indicate successively higher redshifts, and galaxies that are progressively further away from the Earth. (Credit: D. Sobral)
Astronomers announce one of the largest 3D maps of the infant Universe, in a presentation at the European Week of Astronomy and Space Science in Liverpool. A team led by Dr David Sobral of Lancaster University made the chart using the Subaru telescope in Hawaii and the Isaac Newton telescope in the Canary Islands. Looking back in time to 16 different epochs between 11 and 13 billion years ago, the researchers discovered almost 4000 early galaxies, many of which will have evolved into galaxies like our own Milky Way.

Light from the most distant galaxies takes billions of years to reach us. This means that telescopes act as time machines, allowing astronomers to see galaxies in the distant past. The light from these galaxies is also stretched by the expansion of the Universe, increasing its wavelength to make it redder. This so-called redshift is related to the distance of the galaxy. By measuring the redshift of a galaxy, astronomers can thus deduce its distance, how long its light has taken to reach us and hence how far back in time we are seeing it.

In the new work the team used filters to sample particular wavelengths of light, and hence specific epochs in the history of the Universe. ...

Slicing COSMOS with SC4K: The evolution of typical Lyα emitters
and the Lyα escape fraction from z~2 to z~6 - David Sobral et al

Monthly Notices of the RAS (online 14 Feb 2018) DOI: 10.1093/mnras/sty378
arXiv.org > astro-ph > arXiv:1712.04451 > 12 Dec 2017 (v1), 09 Feb 2018 (v2)