A new ‘Einstein ring’ is discovered

PhD student Margherita Bettinelli, of the Instituto de Astrofísica de Canarias (IAC) and the University of La Laguna (ULL), together with an international team of astrophysicists has recently discovered an unusual astronomical object: an Einstein ring. These phenomena, predicted by Einstein’s theory of General Relativity, are quite rare but scientifically interesting. The interest is sufficiently strong that this object has been given its own name: the “The Canarias Einstein ring.” The research was carried out by the Stellar Populations group at the IAC, led by Antonio Aparicio and Sebastian Hidalgo. The results were published in the international journal Monthly Notices of the Royal Astronomical Society.

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I’ve always thought that Einstein rings are very much rarer than I would expect. Short arcs are very much more common. I suspect that the reason is that density in the intervening galaxy has to be uniform in order to get a complete, or nearly complete Einstein ring, and such uniform density is rare in galaxies in the universe.

> The chance discovery was made by Margherita Bettinelli when she was examining data taken through the “Dark Energy Camera” (DECam) of the 4-metre Blanco Telescope at the Cerro Tololo Observatory, in Chile.

So DECam is working perfectly. Great. That’s more exciting news than the discovery of a new Einstein ring.

> DECam

Also, note anything strange about the above image? It doesn’t look like any astronomical image seen before. If those large circular blobs are stars then why don’t they have spikes? If they are galaxies then why are they so perfectly circular and so close together?

(Checks web for details of DECam).
No, I don’t see an explanation on the web. According to the following picture, all stars ought to have four spikes, coming from diffraction off the four supports of the secondary mirror. A mystery.