The Largest "Wheel" in the Universe.

The largest "Wheel" in the known universe comes complete with "spokes".

(Unlike a planetary nebula, which it resembles, this ring encloses thousands of galaxies.)

An image destined to become an icon of physics:

news.bbc.co.uk/1/shared/spl/hi/pop_ups/0...179225191/html/1.stm

Peter.

More here:

antwrp.gsfc.nasa.gov/apod/ap070516.html

The blue ring is a computer generated graphic and not imaged, it was deduced from the galaxies in the image.

Every CCD image is computer generated Dave.

If the computers can repeatedly eke it out of the data...then THE STRUCTURE EXISTS.

I dont take pretty pictures of the night sky so my definition of an image is not narrowly confined just to what astro-photographers call images.

(Imaging the structure of the interior of the Earth does not require cameras for instance.)

It mosty certainly is not an artificial artifact of processing.

It exists

Peter.

It definitely exists Peter, I'm not disputing that, I'm just pointing out that the blue glow wasn't directly captured by the camera, that's all.
Before I realised that, I was wondering how something like that was missed before.

IIf the computers can repeatedly eke it out of the data...then THE STRUCTURE EXISTS.

t mosty certainly is not an artificial artifact of processing.

It's nothing to do with the processing or eeking out data from an image. It's derived from theory and not an observation.

The image posted is an image of the galaxies with the blue glow superimposed to match the mass distribution that could predict the observed lensing effects. The 'ring' has not been observed at all, its an extrapolation based on the lensing features in the ACS image and simulations of lensing. Put another way if the theory or simulation was shown to be incorrect the ring would change - its an representation of the conclusions of a theory not something thats been.

Heres the abstract:

We present a comprehensive mass reconstruction of the z = 0.4 rich galaxy cluster CL0024+17 from Advanced Camera for Surveys data, unifying both strong and weak-lensing constraints. The weak-lensing signal from a dense distribution of background galaxies ( 120 per arcmin^2) across the cluster enables the derivation of a high-resolution parameter-free mass map. The strongly-lensed objects tightly constrain the mass structure of the cluster inner region on an absolute scale, breaking the mass-sheet degeneracy. The mass reconstruction of CL0024+17 obtained in such a way is remarkable. It reveals a ring-like dark matter substructure at r 75" surrounding a soft, dense core at r<50". We interpret this peculiar sub-structure as the result of a high-speed line-of-sight collision of two massive clusters 1-2 Gyr ago. Such an event is also indicated by the cluster bimodal velocity distribution. Our numerical simulation with purely collisionless particles demonstrates that such density ripples can arise by radially expanding, decelerating particles that originally comprised the pre-collision cores.