Intense Star-Formation within Resolved Compact Regions in a Galaxy at z=2 (Swinbank et al. 2010 Nature)
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a) Movie 1: Zoom in from night sky to the cluster, and then into the dust emission [mp4] (6.8Mb)
alternative formats: m4v [15Mb]
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b) Movie 2: HST colour image plus dust emission cross fade (2.4Mb)
More information:
Discovery
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.
Follow-up
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.
Authors
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)
