Intense Star-Formation within Resolved Compact Regions in a Galaxy at z=2 (Swinbank et al. 2010 Nature)

Nature paper PDF available here


Download Figure Captions

a) Artist impression of the galaxy

b) Artist impression of the galaxy with observations overlaid as contours

c) Hubble Space Telescope plus far-infrared colour composition

d) Digitised Sky-Survey of the field of the galaxy cluster (first still from the movie)

e) Hubble Space Telescope Image


Download Movie Captions

a) Movie 1: Zoom in from night sky to the cluster, and then into the dust emission [mp4] (6.8Mb)

alternative formats: m4v [15Mb] ; mov [18Mb] ; mpg [11Mb]

b) Movie 2: HST colour image plus dust emission cross fade (2.4Mb)

More information:


SMM J2135-0102 was discovered from an sub-mm observation with the APEX Telescope. This galaxy is an actively star-forming galaxy at z=2.3 (seen when the Universe was only three billion years old) which has been gravitationally lensed by a factor 32x by a foreground galaxy cluster. Due to the lensing effect, the apparant brightness makes SMMJ2135-0102 one of the brightest sub-mm galaxies known (with an 850um flux of 106mJy), and therefore an ideal laboratory to study the processes of star-formation in the distant Universe.


The redshift (or distance) was measured for SMMJ2135-0102 using the new Zpectrometer instrument on the 100m Green-Bank Telescope through the blind detection of carbon monoxide (CO). This is the first time that a blind redshift has been measured for a targetted galaxy.

Our further follow-up observations with the sub-mm array (SMA) show that we are able to resolve individual star-forming regions on scales of ~0.2", which corresponds to just 100pc after correcting for lensing. For reference, the typical star-forming clouds in our galaxy at 60pc across. Given the sizes of these regions, it is instructive to measure their luminosities and compare these to similar observation in the Milky-Way. We find that, at a given size the star-forming regions in SMMJ2135-0102 are 100x more luminous than typical GMCs locally. However, the star-formation densities are similar to the dense cores of massive giant molecular clouds which are typically ~1pc across. Our results suggests that star-forming regions are a hundred times bigger, and ten million times more luminous, than the dense cores of giant molecular clouds.

  • Dr. Mark Swinbank
  • Prof. Ian Smail
  • Dr. Steve Longmore
  • Dr. Andrew Harris
  • Dr. Andrew Baker
  • Dr. Carlos De Breuck
  • Dr. Johan Richard
  • Dr. Alastair Edge
  • Prof. Rob Ivison
  • Some pretty images (available for download with captions above)