The formation and assembly of a typical star-forming galaxy at redshift z=3 (Stark et al. 2008, Nature)

Download the Nature article here

Hubble Space Telescope colour image of the Cosmic Eye

Velocity field of the galaxy (after correcting for lensing distrortion

Download the OSIRIS Cosmic Eye movie here [image plane only] (5.1Mb)

More information:


LBG J2135-0102 (also known as the "Cosmic Eye" due to its morphological similarity to the Egyptian "Eye of Horus") was discovered from a Hubble Space Telescope (HST) image from an ambitious program to survey high redshift galaxy clusters. This galaxy is a typical star-forming galaxy at z=3 (seen when the Universe was only two billion years old) which has been gravitationally lensed by a factor 28x by a foreground galaxy cluster. The discovery paper can be found in Smail et al. (2007) ApJL 654 33 , whilst the detailed lens modelling used to correct for the lensing distortion is available in Dye et al. (2007) MNRAS 379 308.

Due to its high high magnification, this galaxy has rapidly become one of the best studied star-forming galaxies in the high redshift Universe. In particular, Coppin et al. (2007) ApJ 665 936 were able to detect the cold molecular gas (the fuel for future star-formation), only the second detection of molecular gas in a typical high redshift star-forming galaxy.

Recent Results

Using the Keck telescope with Laser-Guide Star Adaptive Optics (LGS+AO) we have carried out a detailed study of this galaxy. Due to the combination of adaptive optics and lensing phenonemum, we are able to resolve this galaxy on scales of just 100pc. Such fine detail gives us a glimpse of the science that will only be possible with the next generation of telescopes, such as ELT and TMT, still a decade away. The results of this study can be found in Stark et al. 2008 (Nature 9th October 2008).

  • Dr. Dan Stark
  • Dr. Mark Swinbank
  • Prof. Richard Ellis
  • Dr. Simon Dye
  • Prof. Ian Smail
  • Dr. Johan Richard

  • Left: A colour HST image of the "Cosmic Eye". The red source in the middle is the foreground lensing galaxy, whilst the blue ring is the near-complete Einstein ring image of the background star-forming galaxy. Right: A red-gree-blue colour scematic of the rotating galaxy after correcting for lens distortion. The blue area shows the galaxy moving towards the viewer with the red area furthest away. The green area is the centre of the galaxy.

    Download the OSIRIS Cosmic Eye movie here [image plane and source plane] (4.5Mb)

    Download the OSIRIS Cosmic Eye movie here [image plane only] (5.1Mb)