The Australian Dark Energy Survey

Simulation of the Dark Energy in the Universe

Simulation of Dark Energy structure in the Universe. Image: The Millennium Simulation

The Australian Dark Energy Survey (OzDES) survey at the Anglo-Australian Telescope is measuring the redshifts of over three thousand new supernovae, which are being discovered by the international Dark Energy Survey.  OzDES redshifts are measured with the 2 Degree Field (2dF) robot optical fibre positioner which feeds the AAOmega spectrograph.

The supernova measurements will dramatically improve the precision that the expansion of the Universe and the density of dark energy can be measured.  Moreover, is now possible to measure the brightness of supernovae with such precision that scatter previously considered as noise can now provide a unique new signal.  The tiny variations in brightness caused by the gravitational lensing of the supernovae by the matter along the line of sight are now able to be accounted for, which helps in testing gravity on completely different scales to the accelerated expansion.

Measuring the behaviour of gravity on both scales simultaneously will provide one of the most stringent tests of any explanation of dark energy.  Beyond detecting thousands of supernovae, OzDES is also investigating hundreds of Active Galactic Nuclei.  If these AGN can be sufficiently well understood, we can use them to measure the properties of Dark Energy at even greater distances than probed with supernovae, and weigh the supermassive black holes at the centres of distant galaxies.

An image of the Dark energy camera constructed with 74 ccds.

Photo simulation of  galaxy clusters galaxy clusters taken with DECam.

Left: Dark Energy Survey Camera (DECam) is a 570 Megapixel camera constructed from 74 ccds. It was specifically designed to pick up the light from distant galaxies. Image: Edward Macaulay (OzDES)

Right: Photo simulation of  galaxy clusters galaxy clusters taken with DECam. A single image has an area 20 times the area of the Moon on the sky as seen from Earth. Image: Edward Macaulay (OzDES)

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