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Abstract: We study diffuse gamma-ray emission at intermediate Galactic latitudes measured by the Fermi LAT with the aim of searching for a signal from dark matter annihilation or decay. In the absence of a robust dark matter signal, constraints are presented. We present and improve upon conservative dark matter limits obtained with no modeling of the foreground astrophysical diffuse emission. We do so, by taking into account uncertainties in several parameters which characterize conventional astrophysical emission and using a profile likelihood formalism. The resulting limits impact the range of particle masses over which dark matter thermal production in the early Universe is possible, and challenge the interpretation of the PAMELA/Fermi-LAT cosmic ray anomalies as annihilation of dark matter.
Found in: ključnih besedah
Summary of found: ...Dark matter, high-energy gamma rays...
Keywords: Dark matter, high-energy gamma rays
Published: 21.03.2016; Views: 3713; Downloads: 0
Fulltext (1,04 MB)

Found in: ključnih besedah
Summary of found: ...very-high energy gamma-rays, supernova remnants (SNR), SNR RX J1713.7−3946, Cherenkov Telescope Array...
Keywords: very-high energy gamma-rays, supernova remnants (SNR), SNR RX J1713.7−3946, Cherenkov Telescope Array
Published: 10.05.2017; Views: 3996; Downloads: 0
Fulltext (997,39 KB)

Abstract: Over the past decade the multi-messenger astrophysics has emerged as a distinct discipline, providing unique insights into the properties of high-energy phenomena in the Universe. The Pierre Auger Observatory, located in Malargüe, Argentina, is the world’s largest cosmic ray detector sensitive to photons, neutrinos, and hadrons at ultra-high energies. Using its data, stringent limits on photon and neutrino fluxes at EeV energies have been obtained. The collaboration uses the excellent angular resolution and the neutrino identification capabilities of the Observatory for follow-up studies of events detected in gravitational waves or other messengers, through cooperation with global multi-messenger networks. We present a science motivation together with an overview of the multi-messenger capabilities and results of the Pierre Auger Observatory.
Found in: ključnih besedah
Summary of found: ...discipline, providing unique insights into the properties of high-energy phenomena in the Universe. The Pierre Auger Observatory,... ...cosmic phenomena, multi-messenger astrophysical studies, cosmic rays, gamma-rays, neutrinos, Pierre Auger Observatory...
Keywords: high-energy cosmic phenomena, multi-messenger astrophysical studies, cosmic rays, gamma-rays, neutrinos, Pierre Auger Observatory
Published: 06.05.2022; Views: 773; Downloads: 0
Fulltext (1,06 MB)

Abstract: A deep survey of the Large Magellanic Cloud at ∼ 0.1−100 TeV photon energies with the Cherenkov Telescope Array is planned. We assess the detection prospects based on a model for the emission of the galaxy, comprising the four known TeV emitters, mock populations of sources, and interstellar emission on galactic scales. We also assess the detectability of 30 Doradus and SN 1987A, and the constraints that can be derived on the nature of dark matter. The survey will allow for fine spectral studies of N 157B, N 132D, LMC P3, and 30 Doradus C, and half a dozen other sources should be revealed, mainly pulsar-powered objects. The remnant from SN 1987A could be detected if it produces cosmic-ray nuclei with a flat power-law spectrum at high energies, or with a steeper index 2.3−2.4 pending a flux increase by a factor > 3−4 over ∼ 2015−2035. Large-scale interstellar emission remains mostly out of reach of the survey if its > 10 GeV spectrum has a soft photon index ∼ 2.7, but degree-scale 0.1 − 10 TeV pion-decay emission could be detected if the cosmic-ray spectrum hardens above >100 GeV. The 30 Doradus star-forming region is detectable if acceleration efficiency is on the order of 1 − 10% of the mechanical luminosity and diffusion is suppressed by two orders of magnitude within < 100 pc. Finally, the survey could probe the canonical velocity-averaged cross section for self-annihilation of weakly interacting massive particles for cuspy Navarro-Frenk-White profiles.
Found in: ključnih besedah
Summary of found: ...very-high energy (VHE) gamma-rays, Cherenkov Telescope Array (CTA) Observatory, Large Magellanic...
Keywords: very-high energy (VHE) gamma-rays, Cherenkov Telescope Array (CTA) Observatory, Large Magellanic Cloud, pulsar wind nebulas, star-forming regions, cosmic rays, dark matter
Published: 02.06.2023; Views: 29; Downloads: 0
Fulltext (3,66 MB)