Ref HAL: hal-00491478_v1
DOI: 10.1016/j.asr.2007.06.036
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Abstract:

The investigation of the general properties of non-thermal (NT) X-ray shell supernova remnants (SNRs), of which SN 1006 is the prototype, is important to understand how electrons are accelerated in SNR shocks and what is the origin of cosmic rays. Using the XMM-Newton satellite, we are carrying on a survey of putative non-thermal SNR candidates previously unknown or little studied in the X-ray band, in order to investigate the different manifestations of NT emission in SNR shells. The SNRs we have selected are likely to expand in a low density medium, and therefore to have a low thermal X-ray emission, that usually outshines the non-thermal one. We report here preliminary results obtained on the SNR shell DA 530. (C) 2007 COSPAR. Published by Elsevier Ltd. All rights reserved.

Ref HAL: hal-00489473_v1
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difficulties arise in the process of Fermi acceleration at relativistic shocks because they are generically in the superluminal regime and they strongly compress turbulence downstream. Under reasonable conditions usually considered for the turbulent spectrum upstream, cosmic rays do not undergo the scattering that would allow them to make several Fermi cycles. An intense short scale turbulence must be excited in order that the Fermi process can be operative. In this paper, we show the requirement for the turbulence spectrum and give a solution to this issue in the form of the generation of intense compressive waves at short scale upstream. We indicate how the magnetic turbulence compression downstream should not be an obstacle for getting a significant return probability. Thus we conclude that, despite the necessity of some further analysis, the Fermi process at relativistic shock is still promising.

Ref HAL: hal-00489467_v1
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The GAMMA collaboration is studying the possibility of instrumenting the 40 x 40 meter hadron calorimeter structure at the center of the GAMMA array. This mechanical structure, built about 25 years ago, has never been instrumented, and if this could be done, it would provide a valuable addition to the GAMMA array for the investigation of the EAS hadron component and for multivariate analysis of the GAMMA data.

DOI: 10.1016/j.nima.2008.05.015
36 citations
Abstract:

The Alpha Magnetic Spectrometer is designed for a long duration measurement of the cosmic-ray spectra at an altitude of 400 km. The particle rigidity and specific energy loss are measured by a silicon tracker located in a 0.8 T field. Ground results for the position resolution, detection efficiency and charge determination for singly and doubly charged relativistic particles are presented and discussed in the context of the spaceborne detector. (C) 2008 Elsevier B.V. All rights reserved.

Ref HAL: hal-00430449_v1
Ref Arxiv: 0801.4742
Ref. & Cit.: NASA ADS
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The future of ground based gamma ray astronomy lies in large arrays of Imaging Atmospheric Cherenkov Telescopes (IACT) with better capabilities: lower energy threshold, higher sensitivity, better resolution and background rejection. Currently, designs for the next generation of IACT arrays are being explored by various groups. We have studied possible configurations with a large number of telescopes of various sizes. Here, we present the precision of source, shower core and energy reconstruction for gamma rays in the GeV-TeV range for different altitudes of observation. These results were obtained through tools that we have developed in order to simulate any type of IACT configuration and evaluate its performance.

Comments: Proceedings of the 30th ICRC, Merida, Mexico (2007). Rogelio Caballero, Juan Carlos D'Olivo, Gustavo Medina-Tanco, Lukas Nellen, Federico A. Sánchez, José F. Valdés-Galicia (eds.) Universidad Nacional Autónoma de México,

Ref HAL: hal-00430362_v1
Ref Arxiv: 0810.2555
Ref. & Cit.: NASA ADS
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In this communication devoted to the prompt emission of GRBs, we claim thatsome important parameters associated to the magnetic field, such as its indexprofile, the index of its turbulence spectrum and its level of irregularities,will be measurable with GLAST. In particular the law relating the peak energyEpeak with the total energy E (like Amati's law) constrains the turbulencespectrum index and, among all existing theories of MHD turbulence, iscompatible with the Kolmogorov scaling only. Thus, these data will allow a muchbetter determination of the performances of GRBs as particle accelerators. Thisopens the possibility to characterize both electron and proton accelerationmore seriously. We discuss the possible generation of UHECRs and of itssignature through GeV-TeV synchrotron emission.

Comments: Edited by Rogelio Caballero, Juan Carlos D'Olivo, Gustavo Medina-Tanco, Lukas Nellen, Federico A. Sánchez, José F. Valdés-Galicia.

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
Abstract:

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.