Ref HAL: hal-00366563_v1
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Résumé:

The Fermi Gamma-Ray Space Telescope mission, formerly known as GLAST, is the next generation satellite for high-energy gamma-ray astronomy. It was successfully launched on June 11th 2008, and is currently orbiting around the Earth for a planned one-year observation of the full sky. The Large Area Telescope (LAT), its main instrument, with a wide field of view (>2 sr), a large effective area (>8000 cm2 at 1 GeV), sub-arcminute source localization, a large energy range (20MeV - 300 GeV) and a good energy resolution (close to 8% at 1 GeV), has excellent potential to either discover or to constrain a dark matter signal. This contribution reports on current performance of the LAT and reviews the complementary searches for signatures of particle dark matter that the LAT team is currently pursuing.

Ref HAL: hal-00430350_v1
Ref Arxiv: 0806.2911
DOI: 10.1088/1475-7516/2008/07/013
Ref. & Cit.: NASA ADS
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166 citations
Résumé:

We investigate the sensitivity of the Gamma-ray Large Area Space Telescope(GLAST) to indirectly detect weakly interacting massive particles (WIMPs)through the $\gamma$-ray signal that their pair annihilation produces. WIMPsare among the favorite candidates to explain the compelling evidence that about80% of the mass in the Universe is non-baryonic dark matter (DM). They areserendipitously motivated by various extensions of the standard model ofparticle physics such as Supersymmetry and Universal Extra Dimensions (UED).With its unprecedented sensitivity and its very large energy range (20 MeV tomore than 300 GeV) the main instrument on board the GLAST satellite, the LargeArea Telescope (LAT), will open a new window of discovery. As our estimatesshow, the LAT will be able to detect an indirect DM signature for a large classof WIMP models given a cuspy profile for the DM distribution. Using the currentstate of the art Monte Carlo and event reconstruction software developed withinthe LAT collaboration, we present preliminary sensitivity studies for severalpossible sources inside and outside the Galaxy. We also discuss the potentialof the LAT to detect UED via the electron/positron channel. Diffuse backgroundmodeling and other background issues that will be important in setting limitsor seeing a signal are presented.

Ref HAL: hal-00365619_v1
Ref Arxiv: 0803.3458
DOI: 10.1088/1126-6708/2009/03/010
Ref. & Cit.: NASA ADS
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In contrast to previous analyses, we demonstrate a Bayesian approach to the estimation of the CKM phase $\alpha$ that is invariant to parameterization. We also show that in addition to {\em computing} the marginal posterior in a Bayesian manner, the distribution must also be {\em interpreted} from a subjective Bayesian viewpoint. Doing so gives a very natural interpretation to the distribution. We also comment on the effect of removing information about $\mathcal{B}^{00}$.

Commentaires: 14 pages, 3 figures, 1 table

Ref HAL: hal-00339110_v1
Ref Arxiv: 0810.3562
DOI: 10.1126/science.1165572
Ref. & Cit.: NASA ADS
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86 citations
Résumé:

Energetic young pulsars and expanding blast waves (supernova remnants, SNRs) are the most visible remains after massive stars, ending their lives, explode in core-collapse supernovae. The Fermi Gamma-Ray Space Telescope has unveiled a radio quiet pulsar located near the center of the compact synchrotron nebula inside the supernova remnant CTA 1. The pulsar, discovered through its gamma-ray pulsations, has a period of 316.86 ms, a period derivative of 3.614 x 10-13 s s-1 . Its characteristic age of 104 years is comparable to that estimated for the SNR. It is conjectured that most unidentified Galactic gamma ray sources associated with star-forming regions and SNRs are such young pulsars.

Commentaires: 18 pages, 3 figures + supplemental material, published in Science Express, October 16, 2008, Contact authors: G. Kanbach, K. Wood, M. Ziegler

Ref HAL: hal-00927504_v1
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