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Published online 24 July 2009 |
Nature
| doi:10.1038/news.2009.730
Corrected online: 27 July 2009
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Ray of hope in dark-matter hunt
Gamma-ray spike in Fermi telescope data hikes anticipation.
The murky hunt for dark matter has just got a little bit brighter. New gamma-ray results from the FERMI telescope fit with previous tantalizing hints of a detection of the mysterious stuff.
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The gamma-ray spike at energies around 100 GeV is well known within the Fermi-LAT collaboration to be almost certainly due to cosmic-ray contamination. Further work is needed to clean up and understand the data in that energy range, either to remove or subtract the contamination. For that reason, those points were not supposed to be shown in public and were presented in Dr. Drell's talk by mistake. Any conclusions or speculations drawn from those data with regard to dark matter are premature and unwarranted.
http://arxiv.org/abs/0907.2442 http://www.sciencenews.org/view/generic/id/45877/title/Rotation_may_solve_cosmic_mystery "Because dark matter does not rotate..." Dark matter now has large gravitational mass with zero inertial mass. Where lie the phase transitions of curve fitting, ridiculous, and impossible?
Dark Matter is made of nothing substantial and I show why. It is actually multiple gost images of the real matter. That is why dark matter is always in close association with real matter. There will be no dark matter if real matter is not around. I have the concept along with my theory explained at my website: http://cosmicdarkmatter.com/Newtonian_Dynamics.html
Please consider the comment from Dr. Robert Johnson (full member of the LAT team) as the official position of the Fermi LAT collaboration. -Nicola Omodei, Analysis coordinator for the LAT Collaboration.-
As a coauthor of the work mentioned in this story, I would like to clarify a few points: (1) Persis Drell is Director of the SLAC National Accelerator Laboratory. (2) Referring to the signal at around 100 GeV as a "spike" is misleading. There is no spike, merely an excess above the expected background. Most dark matter annihilation models do not predict a spike anyway. (2) We are quoted as saying that the findings are "certainly exciting." We believe this is quoting the conclusion of our paper where we note that it is "certainly exciting" that a dark matter signal can still be present at some level in the data (i.e., is not excluded). The point here is not that the current data set is exciting, as the article we believe wrongly implies, but rather that a dark matter signal could still be present, and that Fermi still has significant discovery potential in the galactic center region. This future prospect is what is ultimately "exciting." We appreciate the comments from the Fermi LAT team about the possible cosmic-ray contamination of the gamma-ray spectrum, and emphasized such caveats in our paper. If the contamination is indeed substantial, then the results in our paper should of course be taken as upper limits. Indeed, we never indicate in our paper that the results should be taken as anything other than upper limits. The Fermi LAT experiment is one of the most anticipated experiments in particle astrophysics, with already tremendously exciting results on many subjects. We eagerly await the official data release in August. -- Doug Finkbeiner, (for the authors)