Tuesday, January 10, 2012 ... Deutsch/Español/Related posts from blogosphere

Virgo favors 20-60 GeV SUSY dark matter particle

This blog has repeatedly updated the story about the ongoing war between Dark Matter Witnesses and Dark Matter Deniers. Some experiments claim that they have seen hints of a dark matter particle in direct searches; others claim that there's nothing there and that the first group has to be deluded. The Dark Matter Witnesses got a bit stronger recently. They usually favor a new particle of mass 10 GeV or so, something like a bino.

A new paper from 2012 tells us what the famous places in the Universe that have previously strengthened our belief that dark matter exists have to say about these matters (if observed by Fermi-LAT for 3 years): I am talking about the Virgo, Fornax, and Coma clusters:

Evidence for extended gamma-ray emission from galaxy clusters
What do they say?

The significance of the dark matter particle detection is going up to 4.4 sigma, in the case of the Virgo cluster, and if the data are interpreted as annihilation of superpartners, the preferred LSP particle mass is between 20 GeV and 60 GeV.

Bonus video: Sylvester Jim Gates and Ylvester Jim Gatesino explain the concept of supersymmetry to the BBC viewers. UK readers may see the whole BBC2 Horizon Program here.

You see that the estimates of the dark matter particle mass differ: 10 GeV in direct searches and 20-60 GeV in the astronomical observations. This weakens the Witnesses' case and/or indicates that something is slightly different than we are imagining.

Map of dark matter web

When I talk about the dark matter, there's another piece of news. A collaboration named CFHTLenS (Canada-France-Hawaii Telescope Lensing Sury) has analyzed images of 10 million galaxies for 5 years and they mapped the web of dark matter: TG Daily, Google News narrow, Google News broad, November 2011 preprint.

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