HEAPOW: Dark Matter Signal? (2014 Mar 24)

[bystander]

HEAPOW: Dark Matter Signal? (2014 Mar 24)

The gravity of the Universe is dominated by dark matter, stuff that only feels the warping of spacetime we call gravity. Dark matter does not produce electromagnetic radiation, so is difficult to see by normal methods. Dark matter holds galaxies and cluster of galaxies together, and forms the cosmic web of the Universe, and which allows normal matter to coalesce into galaxies, stars and planets. Though we can see the effects of dark matter on the motions of galaxies and clusters of galaxies, no one is quite sure of what dark matter is made. The leading model is some type of strange sub-atomic particle, called a Weakly-Interacting Massive Particle, or WIMP. WIMPS can have anti-WIMPS, and if they meet wandering around in the dark, they will annihilate, converting their mass into radiation (and possibly other subatomic particles). In some models, WIMP annihilation produces Gamma ray emission, and this radiation, emitted from enormous swarms of dark matter particles in our Galaxy (and possibly elsewhere) might be detected by space-based Gamma ray observatories like the Fermi Gamma ray Space Telescope. The image above left shows the highest resolution Gamma ray image of the center of the Milky Way yet obtained by Fermi. Scientists have tried to account for all the known sources of Gamma rays in this region, but (as shown by the image on the right) there seems to be an excess of Gamma rays left over. Could this be the long-awaited signal of dark matter annihilation?

Quanta: Case for Dark Matter Signal Strengthens
APOD: Gamma Rays from Galactic Center Dark Matter? (2014 Mar 10)
http://asterisk.apod.com/viewtopic.php?t=33084

The Characterization of the Gamma-Ray Signal from the Central Milky Way:
A Compelling Case for Annihilating Dark Matter - Tansu Daylan et al

• Physics of the Dark Universe 12:1 (June 2016) DOI: 10.1016/j.dark.2015.12.005
  arXiv.org > astro-ph > arXiv:1402.6703 > 26 Feb 2014, 17 Mar 2015 (v2)

Dark Matter Constraints from Observations of 25 Milky Way Satellite Galaxies
with the Fermi Large Area Telescope - Fermi-LAT Collaboration: M. Ackermann et al

• Physical Review D 89(4):042001 (Feb 2014) DOI: 10.1103/PhysRevD.89.042001
  arXiv.org > astro-ph > arXiv:1310.0828 > 02 Oct 2013 (v1), 19 Feb 2014 (v2)

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Author: Dr. Michael F. Corcoran

[MargaritaMc]

http://www.skyandtelescope.com/communit ... 64551.html

http://astrobites.org/2014/03/12/gamma- ... rk-matter/

[MargaritaMc]

NASA: Fermi Data Tantalize With New Clues To Dark Matter
(Excerpt from news release, 2014 Apr 03)
A new study of gamma-ray light from the center of our galaxy makes the strongest case to date that some of this emission may arise from dark matter, an unknown substance making up most of the material universe. Using publicly available data from NASA's Fermi Gamma-ray Space Telescope, independent scientists at the Fermi National Accelerator Laboratory (Fermilab), the Harvard-Smithsonian Center for Astrophysics (CfA), the Massachusetts Institute of Technology (MIT) and the University of Chicago have developed new maps showing that the galactic center produces more high-energy gamma rays than can be explained by known sources and that this excess emission is consistent with some forms of dark matter.
"The new maps allow us to analyze the excess and test whether more conventional explanations, such as the presence of undiscovered pulsars or cosmic-ray collisions on gas clouds, can account for it," said Dan Hooper, an astrophysicist at Fermilab in Batavia, Ill., and a lead author of the study. "The signal we find cannot be explained by currently proposed alternatives and is in close agreement with the predictions of very simple dark matter models."
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