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(Super)voids, CMB coldspots and the integrated Sachs-Wolfe (ISW) effect

6 May 2015

Time: 4:30pm
Venue: G. O. Jones 516
The London Relativity and Cosmology Seminar
Shaun Hotchkiss (Sussex)

There has been some interest and some confusion recently
regarding the effects voids might have on the temperature of the CMB
(primarily through the ISW effect). This has included recent claims that
an anomalous cold spot in the CMB can be entirely explained by the
existence of a "mysterious" supervoid along its line of sight. I will do
my best to make the situation clearer. Part of this process of "making
things clearer" will involve showing that the anomalous cold spot is not
actually particularly cold.
For the rest of the talk I will be questioning whether voids even exist,
and if they do, how we can find them and whether they can be of any 

meaningful use to cosmology.

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