Imprints of structure

Void and cluster imprints on the CMB

This is the main scientific figure of our paper, showing dark energy in action as it stretches supervoids and superclusters to cool or heat light (in this case, the CMB) passing through them.   The Cosmic Microwave Background (CMB) is the most distant light we can see; it’s so far away that the expansion of the universe has stretched it into the radio part of the spectrum.  The ISW effect produces ripples on the CMB that are even smaller than the 1-part-in 10,000 ripples that the CMB has initially, so we had to “stack” small images around each structure to observe the ISW’s effect.

These two images produce spots that are highly significant; taken together, the spots have only a 1-in-200,000 chance of occurring randomly.  This is arguably the clearest detection of the ISW effect to date.  It has been detected before at about the same statistical significance, but those detections involve a somewhat cumbersome combination of galaxies from various heterogeneous galaxy samples (we just use a single sample).

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