| 1. |
- Calore, Francesca, et al.
(författare)
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3D template-based Fermi-LAT constraints on the diffuse supernova axion-like particle background
- 2022
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Ingår i: Physical Review D. - 2470-0010 .- 2470-0029. ; 105:6
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Tidskriftsartikel (refereegranskat)abstract
- Axion-like particles (ALPs) may be abundantly produced in core-collapse (CC) supernovae (SNe); hence, the cumulative signal from all past supernova (SN) events can create a diffuse flux peaked at energies of about 25 MeV. We improve upon the modeling of the ALPs flux by including a set of CC SN models with different progenitor masses, as well as the effects of failed CC SNe, which yield the formation of black holes instead of explosions. Relying on the coupling strength of ALPs to photons and the related Primakoff process, the diffuse SN ALP flux is converted into gamma rays while traversing the magnetic field of the Milky Way. The spatial morphology of this signal is expected to follow the shape of the Galactic magnetic field lines. We make use of this via a template-based analysis that utilizes 12 years of Fermi-LAT data in the energy range from 50 MeV to 500 GeV. In our benchmark case of the realization of astrophysical and cosmological parameters, we find an upper limit of gaγ≲3.76×10−11 GeV−1 at a 95% confidence level for ma≪10−11 eV, while we find that systematic deviations from this benchmark scenario induce an uncertainty as large as about a factor of two. Our result slightly improves the CAST bound, while still being a factor of six (baseline scenario) weaker than the SN1987A gamma-ray burst limit.
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| 2. |
- Eckner, Christopher, et al.
(författare)
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Sensitivity of the Cherenkov Telescope Array to a dark matter signal from the Galactic centre
- 2022
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Ingår i: 37th International Cosmic Ray Conference (ICRC2021) - GAI - Gamma Ray Indirect. - Trieste, Italy : Sissa Medialab. - 1824-8039. ; 395
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Konferensbidrag (refereegranskat)abstract
- High-energy gamma rays are promising tools to constrain or reveal the nature of dark matter, in particular Weakly Interacting Massive Particles. Being well into its pre-construction phase, the Cherenkov Telescope Array (CTA) will soon probe the sky in the 20 GeV - 300 TeV energy range. Thanks to its improved energy and angular resolutions as well as significantly larger effective area when compared to the current generation of Cherenkov telescopes, CTA is expected to probe heavier dark matter, with unprecedented sensitivity, reaching the thermal annihilation cross-section at 1 TeV. This talk will summarise the planned dark matter search strategies with CTA, focusing on the signal from the Galactic centre. As observed with the Fermi LAT at lower energies, this region is rather complex and CTA will be the first ground-based observatory sensitive to the large scale diffuse astrophysical emission from that region. We report on the collaboration effort to study the impact of such extended astrophysical backgrounds on the dark matter search, based on Fermi-LAT data in order to guide our observational strategies, taking into account various sources of systematic uncertainty. © Copyright owned by the author(s) under the terms of the Creative Commons.
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