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- Ackermann, M., et al.
(author)
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Dark matter constraints from observations of 25 Milky Way satellite galaxies with the Fermi Large Area Telescope
- 2014
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In: Physical Review D. - 1550-7998 .- 1550-2368. ; 89:4
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Journal article (peer-reviewed)abstract
- The dwarf spheroidal satellite galaxies of the Milky Way are some of the most dark-matter-dominated objects known. Due to their proximity, high dark matter content, and lack of astrophysical backgrounds, dwarf spheroidal galaxies are widely considered to be among the most promising targets for the indirect detection of dark matter via gamma rays. Here we report on.-ray observations of 25 Milky Way dwarf spheroidal satellite galaxies based on 4 years of Fermi Large Area Telescope (LAT) data. None of the dwarf galaxies are significantly detected in. rays, and we present.-ray flux upper limits between 500 MeV and 500 GeV. We determine the dark matter content of 18 dwarf spheroidal galaxies from stellar kinematic data and combine LAT observations of 15 dwarf galaxies to constrain the dark matter annihilation cross section. We set some of the tightest constraints to date on the annihilation of dark matter particles with masses between 2 GeV and 10 TeV into prototypical standard model channels. We find these results to be robust against systematic uncertainties in the LAT instrument performance, diffuse.-ray background modeling, and assumed dark matter density profile.
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2. |
- Gregory, E.C., et al.
(author)
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An assessment of the suitability of five overcoring techniques for stress determination in a jointed basalt
- 1983
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Reports (peer-reviewed)abstract
- deformation gauge, the C.S.I.R.O. hollow inclusion stress cell, the cast epoxy inclusion, the Lulea triaxial strain cell, and the C.S.I.R. doorstopper'' gauge to assess the suitability of each technique for in situ stress determination in a closely jointed basalt. This effort is in support of the Basalt Waste Isolation Project which is studying the feasibility of locating a nuclear waste repository in basalt. Testing at the NSTF provided information for the evaluation of overcoring techniques so that one or more can be selected to obtain in situ stress data at the reference repository horizon. Even though some problems were experienced, the borehole deformation gauge and doorstopper proved the most successful. 30 refs., 53 figs. 16 tabs.
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